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When I needed a new air conditioner a couple years ago I was quoted $17,000 for a heat pump. I can only guess at that point whatever energy cost savings it would bring would never be realized within the service life of the system. I went with a $6000 standard replacement AC unit.
Unless the installer was ripping you off those were not comparable units. I've seen the manufacturer MSRP sheets and the cost difference between heat pump and non-heat pump for the same unit is small. Nowhere near enough to account for $11k.
It sounds like they quoted you a bottom of the range 11 SEER A/C vs a top of the line multi-stage compressor variable speed blower 19 SEER heat pump system. Those are not the same thing.
Was just going to say I’ve been looking at heat pumps myself and I can’t imagine what the quoted heat pump was that it would cost that much more.
Might have been what I call a "fuck off" quote. That is, the people who gave you the quote didn't really want to do the job (too small, inconvenient location, or who knows what) and so quoted you an outrageous price figuring you'd either decide not to do it or if you did, you'd end up paying enough to make it worth their while. Happened to me a few years ago when I needed to re-tar my roof. The first guy quoted a figure that was like 4x what the next guy quoted.
Not a handy man, but we build power electronics and a lot of customized stuff. I also often give quotes that are really high for stuff that we don't actually want to do. It's kind of better than saying we cannot do it (because then they will never ask again) and if they agree to it we make a lot of money. For larger investments it makes sense to get a second quote.
Don't you think that if you give a really high quote, the customer will never ask you again too ?
What are the rates for both choices?
One has a lower rate of "undesirable outcomes" and thus when the option's binary like that then the choice is clear.
That must have included furnace replacement components for cold weather (e.g electric heat strips).
Otherwise, heat pumps are essentially the same as modern A/C units.
Almost certainly. Proper/modern heat pumps do not need heat strips until -20F or so
Agreed. Ours is at least 5 years old if not more now and was way cheaper. That said there is a difference between mini-split and something you hook up to internal ducting where your furnace used to be and prices have increased in the meantime.
That said there was basically no difference in putting in an A/C only unit vs a combination. Technology wise it's the same so to speak just running in reverse in winter vs summer. We use the heat pump down to -15C-ish then I usually shut it down and just use the baseboard or if awake the stove (looks much nicer ;))
It was a no brainer to get the combination unit really. I don't get why it isn't the default nowadays and A/C and heating are thought of as separate concerns. We just don't have ducting, else we could A/C the whole house vs. just one floor.
Mechanically, there’s a reversing valve and defrost elements and controls to turn an AC into a heat pump. (So, it’s small, but not zero, mechanical differences.)
Thabks for the assist on the tech!
And I can definitely attest to the heating element aka defrost. We don't have actual resistive heat in the pump as we have the baseboards anyway but the lower the outside temp goes the more it has to defrost the outside as it freezes up. As winter goes by, icicles form underneath the outside unit where the defrosted ice drains out and refreezes.
It's actually amazing that the thing can extract heat from -10C air outside to heat up air that's already 21C inside to heat it up even further!
> That said there is a difference between mini-split and something you hook up to internal ducting where your furnace used to be and prices have increased in the meantime.
Generally true, as the mini-splits (have) tend(ed) to operate down to lower temperatures, but the heat pumps that look like 'traditional' outdoor A/C units are getting down there as well: for example this Lennox unit can work down to -4F / -20C:
* https://tech.lennoxintl.com/c03e7o14l/viu12ch2uv/ehb_sl25xpv...
That'll provide pretty good coverage of the year in many parts of North America before something like a gas furnace needs to kick in. (Speaking as someone who lives in Canada.)
They need them installed (and the extra dedicated 240v outlets, which can get expensive) for defrost cycles which happen below 35F or so.
Depends on whether they are reversible or not. Reversible ones, which can act as AC in summer, simply reverse themselves and act briefly as AC, essentially using heat taken from inside the house to defrost themselves. Only a little heat is needed relative to heat capacity of a warm house. Mine does that. However, it still has resistive heating strips for emergency heating and for when the temperature falls too low for it to keep up.
Chicago, so those low temperatures are achievable.
I have a 4 ton air source heat pump. It has both an internal heater and will run a defrost cycle by using the furnace in winter. I put in the full system a couple years ago. The entire system (100k BTU high efficiency furnace with variable output and 48k BTU, 22 SEER2 and 10.5 HSPF2) and the entire system was less than $17k. I also got over 4k in rebates (fed, state and manufacturer).
I'm well north of Chicago. The heat pump is rated to -22F but have the lockout set to 15F to cut over to the furnace. Mostly for wear and tear reasons. But it has a COP rating of 1.75 at 5F. So still more efficient than any furnace well below where I run it.
My understanding is that heat pumps operate at less than 100% efficiency at those levels. They don’t start blowing cold air, rather the air isn’t 90 degrees coming out any more.
What size? The last split system I bought cost about AU$1600 installed ( ~$1060) for 3.5kW... Looking at prices now, even going up to a ducted 14kW Mitsubishi Electric heat pump/AC is only AU$5000 (before installation, and you would need to add ducts and vents etc. - that's just the controller, outdoor unit and in-ceiling unit, but still)...
Is this in the US? Maybe the market is distorted just because not enough people are buying them yet, so nobody has much stock and there's little competition... We have that problem I think for air to water - super common in the UK and Europe, but since everybody uses air to air, split and ducted systems are super cheap but air to water are quite expensive. I really would quite like some heated floors in my bathrooms if I end up doing a big renovation, and don't want to go electric in-floor because hydronic with a heat pump should be more efficient.
For whatever reason both solar and heat pumps are insanely cheap in Australia vs America. It’s mostly in the labor part for some reason. This comes up all the time in the solar subreddit where Americans are routinely quoted at $4.00+ per watt for solar and $20,000+ for heat pump installs.
Heatpumps I kind of get because they’re still rare here (us). But solar is everywhere. I don’t understand how a 350mil person market is so much more expensive for solar than a 30mil one.
The US generally has cheaper labor, less construction rules, and cheaper components due to volume . the solar thing is mysterious to me.
Yep, just installed a 6kw for $2475 (GST inc) and felt like I overpaid. GP is wild.
What kind of a system were you installing? We had a heat pump installed three years ago for less than $5k Canadian. Can't remember if we got a rebate on top of that or not.
I can only speculate, but in my last replacement scenario, higher-SEER units (17+) had dramatically higher quotes, to the point where it was difficult to justify financially. On top of that, there were dramatic (~100%) variations in prices on similar equipment (but different brands) between installers. I can only imagine that regional differences are yet another source of variation...
All that is to say, my first guess is that the GP was quoted a high-SEER unit for name-ish brand equipment.
Had mitsubishi units installed in the northeast USA a couple of years ago, for a 1.5k sqft house all of our quotes were ~15K.
$49k for a Mitsubishi heat pump, variable speed air handler and two ducted head units for upstairs rooms. Supports 3000 sqft with multiple zones.
This comports with my experience pricing out a similar sized mitsu system
Not sure if it's a bit over-priced, however, we replaced a gas furnace without A/C. The variable speed air-handler is amazing for constant low speed circulation and the energy savings with moderate temperature for 60-75 degree weather is incredible.
Also, I have 15k BTU available for one or two additional head units. I opted for this approach instead of under-sizing the heat pump or assuming we'd need the extra head unit and buying them during initial install. Half of our basement has no ducting so we thought a unit for heat would be nice. Also considered adding another unit in second floor landing for additional capacity. Not sure yet if we will.
My only complaint is the Kumo cloud is terrible.
Your temperature controls are dependent on a "Kumo" cloud? that's rather terrifying. What if your internet goes out, or what if the cloud gets attacked (or your smart device)? Does that mean you lose control of your climate control?
Did I ever say they are dependent on Mitsubishi's Kumo cloud? No.
You can use the normal remote controls as well.
They’re right though, the Kumo app is truly awful. Which is sad as it’s also quite useful.
Kumo cloud is beyond terrible and requires wildly overpriced hardware to find that out. I’m so displeased with it I’m on the brink of organizing a class action.
We got a system for around $10,000 Canadian. But then there was a $5000 rebate.
These things are quite expensive. I think the HVAC installers are making a large commission though. The actual equipment costs much less than that.
I have a sneaking suspicion that green rebates are being exploited by historically shady businesses (contractors and car dealers) by baking in the cost of the rebate into the final price.
There’s a local lot with a used 2021 Ioniq with the usual “used car dealer” hand-lettered sign proclaiming the $5,750 provincial rebate. I’m also fairly certain the car had its price inflated by that much by the dealer, or will climb by that as soon as negotiations start.
(1) https://www.apexautogroup.ca/inventory/2021-hyundai-ioniq-el...
It’s naïve to assume 100% of a subsidy will fall on a consumer, though delays between purchase and subsidy help in that respect.
I had the exact same experience last month. I was really excited to go heat pump. It ended up being $8k vs $12k (dual stage) vs ....... > $20k for the heat pump
The guy made no attempt to upsell me and if anything was pushing the cheapest option
Suffice to say I don't plan on staying at that house long enough to ever get my moneys or enjoyment out of it. Bummer.
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I think it's true that the cost only goes up "a little" between models, but the issue is, they make you go up across the board of equipment and it all adds up dramatically. The high end option requires buying their custom thermostat which was $1200 alone
$17k is about right for a top of the line 5 ton Trane XV19 with gas furnace option. The high efficiency/low noise units are expensive.
wow that’s insane. i replaced an oil furnace with a new oil furnace + heat pump hybrid system for 7k in a high COL area.
Wtf, I paid $2K USD for mine. How out of the ordinary were your heatpump needs?
The differences are usually overall efficiency (that Trane is one of the most efficient models, SEER rating of 29.5), noise and overall capacity. This was for a >4000 sq ft house with extensive west facing glazing, not an ideal scenario.
The difference of heat pump an AC is pretty much just a reversing valve, so as others have noted this is probably not an equivalent unit.
One caveat to that is if you have a furnace, they may have wanted to install a full new air handler and run electric emergency heat vs just swapping the coil and condenser.
You can configure a heat pump coil with a furnace as the emergency heat but it might take some more thinking than an off the shelf AHU condenser pairing that maybe the contractor wasn't comfortable with doing that.
Not too far off. I got 5 quotes recently. Most are from $17,500 for $19,000 for a 3.5 ton Mitsubishi heat pump, with an outdoor condenser unit and an indoor fan+coil unit. Permit and inspection from the city add another $1,000.
When my AC finally needs replacing I'm going heat pump, and then also ditching my gas water heater. The constant fees of a gas line are ridiculous at this point and any more electricity usage will be offset by the 9 months of the year I'd never turn on the heat.
Now you can even get water heaters with heat pumps and combo units that dump your waste heat from your hvac heat pump into the water heater. It’s wild.
Your AC powering your hot water heater at the same time... that's genius.
When we put the solar on the roof we bundled in heat pump hot water system as well.
It's timed to only use power right in the middle of the day when the sun is shining, and in the middle of the night when power is cheap. (needs both because the tank is fairly small and my kids like long showers)
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Heat pumps are great, but it’s the dc inverter and advances in compressor efficiency that is really the biggy on energy usage here.
Every one of these “heat pumps are the future” articles is so soft on data, and they often fail to explain the basics or a simple “why.” Once we get past the clickbait heat pump articles, we can actually make an impact.
I think the consensus on why heat pumps _should_ be the future is that you can power them with low carbon electricity, as opposed to literally world destroying natural gas.
A quick Google search says that natural gas -> electricity has an efficiency of about 44%, with an additional 5% loss during transmission. Lets call this about 40% efficiency for getting energy from natural gas to your electric heat pump.
A heat pump operating at 250% efficiency will use just as much natural gas as a furnace operating at 100% efficiency.
Modern heat pumps can often exceed 250% efficiency, making them use less natural gas, even if they are ultimately powered by a natural gas burning power plant.
I made a note for myself to go do this math. You beat me to it and answered the question. Thank you :)
I vaguely recall I did some back of envelope math a couple years back and determined that a natural gas powered heat pump was actually more efficient (in terms of emissions) based on my grid power source mix. Solar breaks that equation obviously.
I think many people suddenly realized that moving heat translates to efficiencies far north of 100%, also for heating. Moving in opposition to creating heat, which tops out at 100% in the best case.
Plus, they can run on any power source, including green and/or decarbonized.
Above 100% being 350-400% in home heating cases.
They're quite popular in the Netherlands due to high natural gas prices (since the Ukraine war) and two types of government subsidies. One is a direct subsidy on buying a heat pump device, the other is based on our energy pricing.
Basically you can offset all energy-taxes across the year with solar production. Everything you over-produce in summer carries over to the winter. So if I assume for example that my solar system is written off in 10 years to zero (reality is probably better than that) my total energy cost per kWh is only 7 cents all year round.
A pretty low capacity heat pump is able to provide 90% of the heating and cooling of a normal house. They're combined here with gas based systems to cover for the few days a year that it's exceptionally cold or when you need more hot water than the heat pump could deliver. That means you can buy a much smaller capacity (cheaper) heat pump.
If you compare the running cost of heating at only 7 cents per kWh with a heat pump to natural gas prices "pre Ukraine" it'a already roughly about 4 to 5x cheaper. Now with gas prices nearly doubled you're looking at a 8x cost saving with a heath pump vs using natural gas. The only hurdle is that you need to buy and install a heat pump device, so it takes some time to make that back.
The government is planning to slowly reduce the energy-tax offset from 2025 to 2031. But even without that it's expected that the move from gas to heat pumps will continue.
The article mentions the most important point towards the end: “The better you insulate, the less heat you need in the first place,”
No heat pump will help if your house is leaky or under insulated.
I have new heat pumps in a very old, under insulated, and leaky house. I didn't use my oil furnace last winter (the first since two additional pumps). My costs were about half of the previous year, and I'm sure my carbon footprint was much better as well.
Can you say more about what your comment is supposed to mean?
Not OP, but my assumption is that better insulation means you need less heating and cooling.
I've lived in a home with a literal hole to the outside. During the winter we had to run the radiators non-stop and it was still freezing.
If you are trying to save energy, then sealing up and improving insulation will generally have the largest bang for the buck.
Our house (in Europe) is relatively old and not well insulated by modern standards, and all of the advice we read and receive from experts is that heat pumps are not a good fit without additional insulation.
The gist is that we’d need to spec larger units and/or run them harder than usual, removing savings vs. gas.
It doesn't really matter. You should insulate anyway to save energy, but a heat pump will still use 1/4 the energy as resistive electric for the same heat. Depends on your gas prices as to whether it's worth it, but it almost certainly would be.
A worked example - In AU gas is metered per MJ - 3.6MJ/kWh. So 3c/MJ means that gas is equivalent to electric heat at 12c/kWh. Heat pump multiplies that by roughly 4x, so 48c/kWh is the Breakeven point for a heat pump vs gas heating.
Heat is heat, it makes no difference. insulation would save you money on all heat sources though, and can be a pretty cheap upgrade (insulating the roof space, for example).
They give that advice because 'experts' (you probably mean salespersons) have to simplify a somewhat complicated story in a single recommendation for their market.
We can assume that you currently have a high power (e.g. 28kW+) gas heater and radiators that can only emit that kind of power at high water temperatures. This system works in tandem (place where has is burnt and devices that emit the heat throughout the house). A leaky house typically needs a higher heating power in the interest of comfort: it'll have a higher power loss, and you'll want to not spend days bringing it up to room temperature in case the power was out or what not. These heating systems are usually overdimensioned, so any variability in the power loss of the house is compensated for by simply upping the power output.
A heatpump is lower power, and therefore slower, and therefore you'll want to limit the heat loss of the house, because when things go wrong (somebody left a window open in winter), you're gonna have to wait some time before the pump's caught up. Calculating a building specific optimal heat pump power is already trickier, and it's trickyness is increased without that insulation.
Which doesn't meant that you cannot do it yourself! You can simply accept that response times are going to be slower (so, if you flip the temp up from 17C to 20C that it's gonna take half a day). Best is to just set it to a temp and leave it there, it's no longer the advantage it was to modulate.
Most important is to not underdimension the heat pump. I've never seen a salesperson offer it, but there's online communities of people who can and do calculate it for older houses (gas consumption is a good proxy). One thing to understand is that heat generator power (be it a heat pump, gas heater, whatever) needs to match the heat emission power of the system that releases the heat (radiators and floor heating most likely). The water is gonna run at lower temps with a heat pump, so that means that your radiators will emit less heat, and probably not enough. You need to make sure that at the water temp the pump outputs economically the power output of the delivery system matches. This usually means putting in floor heating and/or significantly larger and more efficient radiators.
Isn’t insulating a house way more expensive than buying a bigger heat pump and paying for extra electricity?
It probably depends on what kind of insulation work needs to be done.
My parents' house in France is one of those hundred-year-old stone ones. It's fairly cool in the summer, but it gets quite cold in the winter. My father did the insulation work himself (he's not in construction) for fairly cheap and saw his gas bill halve.
The usual other option is to look at increasing the size of the radiators, then you can lower the flow temperature and you still get big efficiency savings.
They mean that your bill and footprint would have been even lower if it were better insulated and less leaky.
Without fixing leaks and insulation, you've done the tech equivalent of throwing large amounts of resources at the problem rather than fixing the root cause :) Your CO footprint will be far better if you decided to fix the leaks & insulation.
This is a pretty broad topic, and you can watch videos from this channel to learn more: https://www.youtube.com/watch?v=dReyrSGokEQ
There are options to do a full passive house retrofit, or just add exterior insulation if you have the funds and inclination. Plus you can get better air quality with filtered air, lower mold/pollen issues, lower noise if you care about that and overall home comfort.
https://www.buildwithrise.com/stories/passive-house-retrofit...
Sure they can, you can absolutely use heat pumps to brute force it, been there done that.
Not only that, but since a heat pump is at least 3x as energy efficient as the most efficient gas furnace, using one results in about 1/2 the E2E CO2 emissions as the gas furnace when the grid electricity being consumed is natural gas based. If you live in an area with abundant zero emissions electricity, then you are heating without any C02 emissions at all.
That said, we should do both heat pumps and insulate better.
Your numbers are off. Thermal power plants typically do have a thermal-to-electric efficiency of around 30% (40% max), so with your heatpump having an electric-to-thermal efficiency of an assumed 300%, you end up with basically no difference in CO₂ emissions.
Note that there are some misleading efficiency claims for gas plants around 60%, but those are not for thermal-to-electric efficiency but for generating electricity plus district heating from waste heat.
Modern combined cycle gas turbines offer thermal-to-electric efficiency over 60% (on a lower heating value fuel basis) at full design load, e.g. this General Electric system at 64%:
https://www.ge.com/news/press-releases/ha-technology-now-ava...
Approximating natural gas as 100% methane, that means the thermal-to-electric efficiency on a higher heating value basis is more like 57-58%:
https://en.wikipedia.org/wiki/Heat_of_combustion#Heat_of_com...
Neither of these efficiency measures include district heating with waste heat.
60% would be terrible thermodynamic efficiency for a cogeneration plant. Modern CCGT systems crack 60% thermodynamic efficiency for just the electricity generation. With cogeneration, system efficiencies are typically in the 70-80% range.
60% is feasible for e.g. nuclear and gas, if you use more than one turbine and there is a big constant temperature differential. This typically isn't the case for gas plants which are intentionally variable and often intended to be cheap to build. While at peak temperature, they might run at peak efficiency around the theoretical maximum of 60% (thermal to electric) with a multi-turbine assembly, typically efficiency is far lower because gas plants usually don't run at peak efficiency and only have one turbine.
I don't think that any nuclear reactor has achieved 60% thermal-to-electricity efficiency. In a water cooled reactor the hot side starts with cooler steam than a combustion-fired plant can generate so it's hard to reach really high efficiency. Reactors cooled with helium, molten salts, or liquid metal could theoretically do better but I don't think that any actually-built power reactors have reached 60%.
The brand new EPR achieves only 37% thermal efficiency and that is considered a good number for a power reactor:
https://www.world-nuclear.org/information-library/nuclear-fu...
No, you are right, 60% is a theoretical maximum achievable maybe with supercritical reactor coolant. The actual maximum for existing reactors is somewhere just below 40%.
Keep in mind that pure gas heating is also not 100% efficient because you need to remove the exhaust, meaning you need to use a heat exchanger and no heat exchanger is 100% efficient either. Some of the heat gets carried outside.
Sure but these days even the cheap stuff is around 95% efficient because that enables the use of cheaper plastic exhaust pipes instead of insulated metal.
And it's irrelevant. Everyone is like "but if you have better insulation..." well golly gee, guess I'll get right on that. Tearing out all my drywall? Re-sarking my roof? Cost-free! Definitely not hugely disruptive, invasive and expensive activities which stand a good chance of forcing me to move out of my house while the work is complete...
People love throwing in about how effective insulation is, completely ignoring the vast difference in difficulty and cost it actually represents.
I wouldn't say irrelevant but definitely nuanced.
Putting more insulation in the attic does not mean redoing the roof. Depending on what you have it might just be blowing in some insulation or adding matting. Of course there are options like spray foaming but it's not the only one.
You are of course right that if your walls are completely uninsulated you will probably want to rip out that dry wall and that will cost you. Maybe blown insulation is an option too depending on your specifics.
Do some math and see if it makes sense to do it if you don't want to do it purely for the sake of the planet. Drywalling isn't that big of a deal actually. The worst would be the ceiling and you don't have to touch that. Regular drywall on a wall is easily done solo by a home owner. Been there, done that.
It's funny what money makes you do. I had a choice to pay tens of thousands to have professionals do it or pay hundreds for materials and do it myself. I did lots of TIL and I have beautiful white walls again.
There are other advantages to fixing leaks & insulation such as controlling humidity/moisture, lowering mold/pollen/dust, lower noise, adding better air filtration, maybe even better fire protection. By "lower" I mean you can eliminate some of these issues. Not to mention a far lower energy bill. I would not describe these as irrelevant to most people.
Depending on the house, location and condition, adding exterior or interior insulation and/or aero barrier, or spray foam could be more cost effective and not so invasive as you think.
https://www.youtube.com/watch?v=_nOI99ew5MM https://www.youtube.com/watch?v=eYjF1afRqvE
Never mind that you really, really can't do anything about that if you're renting.
It's actually exactly the reverse: for a house that's well-insulated, it barely matters how efficient your heating and cooling appliances are, especially if you're considering replacement of working systems.
The worst is when you rent. I live in an area that doesn't really expect much cold or heat. All the windows are single paned. The sun beating on the roof raises the top floor to the outside temperature plus 5 degrees. I can't fix any of it because I'm only here for a few years.
Some jurisdictions will actually basically pay the landlord to improve those things, worth checking community block grants and other similar search terms for your location.
Renting is a pain for heat pumps too, why would a landlord spend extra on one when they can pass the cost of utilities on to the tenant?
It's kind of nice in cool climates. I've rented places where I never had to turn on the heat once all winter thanks to all the heat coming up from lower floors. Temps were almost always above 60F and usually above 65 which is perfectly fine for cozy sweaters and blankets.
This is something to consider for a future rental property.
You’re describing my situation. How do you de-leakify a house?
> You’re describing my situation. How do you de-leakify a house?
Do a blower door test and see where the air is coming in/out:
* https://www.energy.gov/energysaver/blower-door-tests
* https://www.youtube.com/watch?v=msZ_E-4GFs8
* https://www.youtube.com/watch?v=Q5vHxgq7GKo
Then plug the holes.
Aero barrier and/or spray foam for an existing home should work well. But they are not long lasting and are often not environmentally friendly. You can also look into exterior insulation.
If possible and if you have the funds, try to do a retrofit: https://ekobuilt.com/2019/04/24/retrofitting-an-older-home-t...
https://www.buildwithrise.com/stories/passive-house-retrofit...
You don't have to do all the the things to improve performance -- you can pick and choose.
I would start by blowing insulation into the exterior walls (assuming they don’t have any), and insulating the attic. Also, upgrade the windows to double paned or better.
Fixing unintended holes in exterior walls is probably also reasonably safe.
However, randomly plugging intended leaks without understanding how the house is supposed to breathe can lead to condensation issues (mold and rot), carbon monoxide poisoning (if you have natural gas) and radon poisoning (if that is a thing where you live).
If you want to do more than I mentioned above, consider hiring an architect, or reading up on house ventilation designs.
Some home energy companies will do a free audit, in my case it's Mass Save. My in-laws on a limited income even got new windows and insulation for free.
AeroBarrier does the spray insulation strategy all at once for a whole home. Could look into something like that.
- spray foam around/behind outlets on exterior walls (major leak point) which can be done often by just removing the outlet covers
- spray foam around windows (requires removing trim)
- caulk joints/spray foam rim joist in basement/crawl space
- spray foam around any attic can lights/duct work
- make sure ducts and air returns are sealed properly
The easiest is honestly to remove the siding and roof, and wrap the entire building in insulation.
Insulation also matters for keeping your house cool and improving AC efficiency.
Isnt any a/c a heat pump though?
Yes, but typically “heat pump” is used to mean it can provide heating too, whereas standard “A/C” is a “one-way” heat pump that only provides cooling.
I always went with this description too, though oddly a "heat pump water heater" only works one direction, yet "heat pump" is still in its name.
all heat pumps work in one direction. You can't move cold around with any mechanism. Only heat can be moved. The difference is residential "heat pumps" just have a set of reversing valves so you can move heat from outdoors to indoors.
> The difference is residential "heat pumps" just have a set of reversing valves so you can move heat from outdoors to indoors.
So.. they work in two directions.
It depends on your frame of reference.
A "heat pump water cooler" also exists and is better known simply as a water cooler. You know, the one that people gossip around.
Have to imagine that the niche market for making 40F/4C "cold" water from luke-warm tap water (if you live in an area that is so hot the tap water is warm) is fairly small.
It's not a niche market. Every office in the world has a water cooler.
The market for evaporative water coolers is niche, or probably only big in the developing world. Other than that water coolers use refrigeration aka a heat pump.
Naw. Every office in the world has a water dispenser misnamed "cooler".
Ive only ever seen water coolers in the US, mainly in the South, and they're loud
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Every fridge with a cold water tap is literally this (in addition of being a fridge and a freezer, obviously)
My Frigidaire fridge doesn't seem to have a water reservoir, so the water dispensed is room temperature. (And eventually tap-cold temperature.)
Perhaps think of "heat pump" as something that can (also) bring heat into a building, whereas A/C generally (only) removes heat from it.
An A/C is a heat pump. Stop trying to change existing terminology
In the trades in the US we would exclusively use the term heat pump to describe a system where the “indoor” or “outdoor” coil can change from condenser or evaporator depending setting. Us HVAC guys would generally call a conventional system a conventional DX system (for direct exchange rather than chiller) or a split system (like a mini-split, minus the mini).
I work in the HVAC industry and "heat pump" in the context of A/C units exclusively refers to models that cool and heat by reversing the refrigerant flow.
I've only ever known the term "heat pump", in the context of HVAC, to mean "an air conditioner that can also be used to heat".
Everyone in this thread might benefit from a little research before posting...
https://www.iea.org/reports/the-future-of-heat-pumps/how-a-h...
or a simpler article https://en.wikipedia.org/wiki/Heat_pump
It is different from a radiator or a furnace.
> An A/C is a heat pump. Stop trying to change existing terminology
I am not trying to change existing terminology, I am using existing terminology. Air conditioners (A/C) are devices sold to only cool a house:
* https://www.lennox.com/products/heating-cooling/air-conditio...
* https://www.carrier.com/residential/en/us/products/air-condi...
* https://www.trane.com/residential/en/products/air-conditione...
Heat pumps are devices sold to both cool and heat a house:
* https://www.lennox.com/products/heating-cooling/heat-pumps
* https://www.carrier.com/residential/en/us/products/heat-pump...
* https://www.trane.com/residential/en/products/heat-pumps/
* https://www.ehpa.org/about-heat-pumps/
See also US Department of Energy:
* https://www.energy.gov/energysaver/heat-pump-systems
And most definitively of all, Alec of Technology Connections:
It feels like very much a could country / could region distinction. In warmer regions of the world, heat pumps have been using for efficiently heating in winter since the 1980s (that's as far as my memory goes). Of course, when the temperature rarely went below 0℃. If you look at the single-room AC units that now dominate these markets, you'll rarely find anything that cannot do both heating and cooling.
Interesting, I’ve never heard of that interpretation. Heat pumps have always been a technology to me. The same tech that is in everyone’s refrigerator.
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To confuse matters, "mini split AC" seems now to mean that it can also heat.
Technically, from the point of view of physics, yes. That said straight cool systems (alternate name for air conditioners) are only one way heat pumps (in a physical sense) as they lack the reversing valve needed to reverse the heat flow. Heat pumps (in the common sense) can move heat in either direction.
Here in Europe all modern ACs have that feature. The difference with heat pumps is that they're bigger and usually use underfloor pipes.
Compared to a traditional air conditioning unit, the reversing valve is the major difference. Your standard AC can only move heat from indoors to outdoors. A heat pump can do the reverse to warm your space. My basement heat pump is rated to provide heat even when it’s -20F outside.
I think any and all AC units sold in europe (split systems with inside and outside module) can do heating and cooling just fine with great efficiency. Many models rated to work at -20C, sometimes -30C
Pretty sure all acs sold here can reverse and heat a bit.
I think the media has once again assigned a term their specific definition and created a meme out of it. I guess it makes sense if you have no preconceived notions of what a "heat pump" is. But yes, to anybody that knows an air conditioner is a type of heat pump, these articles read akin to "Personal cars create too many emissions. Companies have come up with an innovative way to reduce this problem: vehicles". (with the reader in the memestream of taking the generic term "vehicles" to mean only electric vehicles)
Trying to parse the mumbo jumbo, I think these articles are trying to point out and encourage the trend of designing new installations of cooling systems around cooling and heating, with a reversing valve and whatnot. Because it no longer makes sense to lean on a separate heating system that burns fossil fuels. But gosh I wish they would just come out and say this directly instead of beating around the bush as if "heat pumps" are some magical new invention.
It’s not the media doing this; “heat pump” has been industry lingo (in the US at least) for an A/C with a reversing value since at least the early 1980s.
My parent’s house had a heat pump then and does so today (albeit much improved over the decades).
I'm aware of HVAC lingo, but that's not the entirety of it. The media is explaining them as if they're some completely different advancement, rather than focusing on the commonalities. Look at this nonsense:
> Heat pumps are also compatible with natural refrigerants with lower climate impacts. They can consume less electricity than conventional central air conditioners
Like no, any efficiency gains for cooling have nothing to do with a unit being a "heat pump". And same thing with refrigerants - adding a heating mode can only constraint the choice of refrigerants. So they're touting benefits that have nothing to do with "heat pump" and everything to do with newer technology - but instead of describing this accurately, it's just being ignorantly lumped under this "heat pump" banner.
It’s not just a heat pump thing, it’s the entire industry. The state of science and tech journalism is pretty sad right now.
That’s what happens when few people are willing to pay for quality research and writing.
All that said, it is relatively recently that Americans have had access to heat pumps this efficient and they work reasonably well in sun-freezing temps.
I grew up with heat pumps. It was pretty normal for it to kick into emergency (electric heat element) when the weather got nasty (for DC, so the mid-teens F).
I agree, but I'm specifically calling out the treatment of heat pumps here because that is the topic under discussion. A meta point about journalism as a whole wouldn't really be on topic, nor easily applicable.
I don't have heat pump experience, or even much central AC experience, but I do know that there has been many advancements that make them practical for a wider audience rather than the previous niche. I wish articles would describe these advancements rather than effectively saying "a heat pump is this new awesome invention, go buy one".
Yeah, that's the part of all the "heat pump" coverage that I find amusing and odd. I've lived with a heat pump for at least 40 years at this point. Every house I've lived in for the last 40 years has been fully electric actually.
I have never really understood the difference between a heat pump and an A/C myself.
Any expert care to explain it in layman's terms?
In physics we call a device that uses the compression and expansion of a fluid to move heat between parts of a system a heat pump.
An air conditioner uses a compressor to convert a refrigerant and sends the compressed fluid through a condenser. The condenser rejects heat from the system into the environment. This is the component of an air conditioner that is found outside. The compressed fluid is then passed through an expansion valve and into an evaporator where it is allowed to expand. Expansion is a process that requires heat. The heat flows into the expanding fluid from the environment inside the home. Air is blown across the evaporator coils to transfer heat energy from the home into the fluid which is then returned outside.
A heat pump is capable of reversing the flow of heat energy. The flow of fluid is reversed from an air-conditioner using something called a reversing valve. The compressor sends compressed fluid into the home where heat is rejected through the evaporator coil. The fluid then flows into the condenser coil and is allowed to expand outside, drawing in heat from the outside environment. The heated fluid is then returned to the compressor and the cycle continues.
In HVAC terminology an Air Conditioner is a one way physical heat pump and a heat pump is a bidirectional physical heat pump. Hopefully that helps clear it up a bit.
An A/C works almost identical to your refrigerator. Using a closed loop of refrigerant with specific thermal properties, it will remove heat from one side and emit heat from the other.
If you are able to run this system backwards, you could in theory swap which side is a heat sink (the cold side) and heat source (the hot side). While a traditional A/C cannot do this, heat pumps can electronically switch which side of the system is collecting the heat and which side is releasing it.
This is an improvement over resistive heating (think space heater) because we’re not pumping electricity into some filament that resists current flow and emits off heat due to the resistance. Instead, we are taking heat from inside and moving it out or taking heat from outside and moving it in.
Fun fact, a resistive heating device is a rare case of something being 100% electrically efficient in that all the energy it uses will be turned into heat, whereas heat normally is a byproduct of imperfect conductors, which everything is, and is therefore considered wasted energy in almost all other applications.
> Fun fact, a resistive heating device is a rare case of something being 100% electrically efficient in that all the energy it uses will be turned into heat
My understanding is that you get considerably more heating per watt-hour with a heat pump than with resistive heating, though. I get that it's not creating that heat but moving it, but still that seems like even more efficiency from the perspective of energy consumption per useful heat made available.
Well the word “efficient” always needs context. You have to define the goal first before you can define efficiency.
OP said electrical efficient so the goal is conversion of electricity to heat and it’s 100% efficient.
Even an electric heater compared to a propane heater is more electrically and energy efficient, but it’s not as storage-efficient (because fossil fuel gases have much higher energy density per volume AND weight than lithium batteries).
A heat pump is more electric bill-efficient.
> OP said electrical efficient so the goal is conversion of electricity to heat and it’s 100% efficient.
I am not an engineer and I am only nitpicking to have fun, so don't engage me if it's not fun, but doesn't some of the energy go into degradation of the materials used to build the device?
Yes, but energy is not consumed by that process, it is only converted into heat. The degradation usually is a result of the heat produced. If we’re talking about mater to energy transitions, we need to start talking about special relativity.
I said 100% electrical efficiency because from the prongs of the plug, through the conductors in the appliance cord, the rheostat, all electrical connection and contact points, and of course the hearing element itself all will product heat as a consequence of electricity flowing through, and being resisted by, it’s various components.
It was pointed out that this does not mean “energy bill efficient” which is totally correct: this whole thing is a somewhat silly thought experiment to consider what it really means for something to be efficient.
The coefficient of performance of a heat pump isn't a measure of thermodynamic efficiency, because as you pointed out, a heat pump moves heat rather than creating it. That's why you get more heat per Watt-hour, because you aren't expending energy trying to make heat.
The closest analogy that I know of is in electrochemical processes where some of the energy input is allowed to take different forms. If you put in 85 units of electrical energy, 15 units of waste heat from a different process, and get 90 units worth of product, your process is 90% thermodynamically efficient, but has better than 100% electrical efficiency. In the case of a heat pump, measuring units of heat per Watt-hour is a bit like this in that some of the input energy (for the heat generation) has already been provided by a different process.
The difference is whether you add a $20 of valves to let it run in reverse (and possibly some extra smarts to keep it from frosting up)
A heat pump is an A/C with a reversing valve; in A/C operation, the A/C cools the inside and heats the outside; in heating operation, the reversing valve is toggled and the system heats the inside and cools the outside.
It's kind of confusing terminology. I'll stick with how these terms are used by industry/laymen - heat pump also has a scientific definition that's more broad than how it's normally used.
There's a process called a "vapor compression cycle" which essentially works by moving energy from a cold area to a hot area (which makes the cold area colder and the hot area hotter).
Air conditioning is when you put the cold side of a vapor compression cycle in a building to keep it cool.
The term "heat pump" most typically refers to a device where the hot side of the vapor compression cycle is put in a building to keep it warm.
However, many heat pumps have an air conditioning mode, where the hot and cold sides of the vapor compression cycle switch places depending on the season. So air conditioner refers only to cooling, while heat pump may refer to heating along or a device which can both heat and cool.
* A/Cs are heat-pumps (when using the scientific definition of "heat-pump")
* Heat pumps, when referring to HVAC technology specifically, refer to systems that are essentially the same as A/C units, except they're designed to work in reverse.
* The term "heat pump" when used in Europe, more-often refers to geothermal heat-pumps ( https://en.wikipedia.org/wiki/Ground_source_heat_pump ) which is very different to an A/C-style heat-pump, though achieves similar end-result (livable indoor room air temperature).
As someone who spends a lot of time in the year in both North America and Europe I frequently come across people confusing the two.
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I think a lot of American houses have central air with A/C systems that cool, and a furnace that heats rather than the AC, if I understand correctly.
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Please stop with these sorts of posts, it's the 2023 equivalent of "let me google that for you"
Only if they used GPT 3.5, if they used GPT 4.0 is more like someone using their paid access to a subscription to a scientific journal to look up research papers for someone.
Not really - a scientific journal contains information of a high quality. The fact that money is involved here makes no difference. A better analogy would be using your paid subscription to a horoscope.
I believe heat pump is limited to reversible systems, while an AC is one way. It's just a more limited variant.
Strictly speaking any compressor AC is a heatpump, but more colloquially, "heatpump" usually refers to reversible or heating-only units.
Yes modern day a/c is usually a heatpump. I’ve noticed a lot of people misunderstanding heat pumps, and thinking it’s some sort of replacement for A/C. Or that heat pumps are some new tech.
The key difference in modern systems is the variable speed control and two way operating.
And different gas/liquid allowing operation in much colder environments.
And isn't the refrigerant the same with a heat pump?
The article says that heat pumps are "compatible with natural refrigerants with lower climate impacts". Why couldn't A/C units use the same natural refrigerants?
In a technical sense yes, outside of niche systems such as evaporative coolers.
Also all refrigerators contain a heat pump.
It's an industry term for mechanical equipment that can heat AND cool. One piece of equipment replaces your AC AND heat source.
Heat pumps in particular are getting a push from "green" initiatives because they only use electricity for fuel which can potentially be supplied by "renewable" sources.
ie; it's a buzz word.
It's not just buzz. It's more efficient than resistive heating and modern units have better performance in cold temps. Hence the push to promote them. The downside is that you have added complexity driving up installation costs and reliability down.
Walk around in the American Heating and Refrigeration conference for a while to get a feel of these trends, this was specifically called out by many manufacturers as driven by the green movement.
It's being driven by government pressure to reduce energy consumption and dependence on fuel imports. That isn't a bad thing. It's the sort of thing a responsible government should be planning for.
Natural gas is available in abundance, is nearly free in terms of cost, and is vastly more "green" than many alternatives available today.
It may not be as green as pure electric can be in theory, but in large portions of this country electric isn't all that green either.
Heat pumps appear expensive to operate. Imagine running your AC year-round... that very thought makes many-a-homeowner shudder.
Heat pumps are expensive to operate, and a nightmare to fix. There is a big movement to build whole subdivisions without using natural gas at all, electric ranges and heat pumps. I don't know why it upsets me so much but it does.
Heat pumps for homes aren't expensive to operate. They are cheaper to "operate" than resistance heaters. I doubt they're a nightmare to fix - I have actually had to get mine "fixed" once. It was still fairly new, and it turned out there was a leak in the tube so the coolant gradually (over the last year) got out. The company came and fixed that easily enough. Since then (January 2011) the heat pump has been running 24/7 with no issues whatsoever. In fact you're not supposed to turn them off at all, the moving parts are supposed to keep moving. So, if I'm away for some weeks I simply set the temperature to the recommended "idle" temperature of 17C, which in practice means it's not really doing any work, but it's not off either.
Well, the no-gas thing upsets me because cooking on modern electric cooktops/stoves is still staggeringly awful.
Induction cooktops heat faster and more evenly than gas
There's many good reasons induction cooktops aren't used in commercial kitchens... and those reasons apply for home-cooks as well.
But they are used in commercial kitchens. I joined a cooking course arranged by a well-known restaurant where I live, and to my surprise the kitchen we used used induction. Very easy to operate, and you could easily set the heating exactly. It worked basically as a gas restaurant kitchen, just without the gas.
Woks suck on induction by design and that’s pretty much it. The rest is uniquely US problem of not having 400V installations.
you have wok shaped induction plates that work extremely well
It's a niche, I give you that, and the plate can only be used with specific sized woks, but they exist.
Inertia? Ignorance?
I've seen induction cooktops in commercial kitchens before, maybe they were just being stupid?
Being responsible is so trendy.
That doesn't make them a buzz word.
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> because they only use electricity for fuel which can potentially be supplied by "renewable" sources.
They also can operate at >100% efficiency. Under the right conditions (I'll let someone who knows more about it fill that in) they can provide more heat than the same amount of power going into a resistive heater (which is I think per-se 100% efficient right?). Kinda wild.
This should happen under a fairly wide range of temperatures for modern heat pumps. Quoted figures are usually in the 3-4x more efficient than resistive heating when adjusted for seasonality for air source heat pumps. Ground source are more like 5+ I think.
That's lab figures though so I guess similar to car efficiency figures.
OR another (incorrect) way of thinking is that resistive heating is 100% efficient as every bit of heat generated is inside the home. VS mechanical heat has some "loss" with some of the heat being left outside the home.
But yes, mechanical might be up to 600% efficient depending on how you think about it as moving heat around based on energy usage per therm delivered inside the home is really what people are looking for.
Why put renewable in quotes? Because it isn’t 100%?
Basically yes. Renewable is more of a supplement to current grids for most of us. There might be a couple rare few areas that currently claim 100%.
Vs the alternative, natural gas, which is famously 100% renewable?
Master-Blaster rules Bartertown!
Same principal. But an aircon pumps the air over a radiator cooling/heating it, with a fan. Heat pumps rely on radiators in the room to cool/heat the ambient air generally.
Wow, I never cease to be amazed at how few of the HN comments have anything to do with the original post.
I guess I'll jump on the bandwagon, while my comment is tangential, it does have to do with the article's focus on reducing greenhouse gases and fuel consumption.
Switching to a heat pump should be done in all cases where a traditional A/C is being replaced, but the biggest bang for the buck is in how the house is constructed in the first place. "Passive solar" orientation and insulation can prevent a HUGE amount of energy consumption. To point to another HN post article:
https://thebaffler.com/salvos/construction-time-again-sisson
I've been saying for 20 years here in San Diego county, that if developers built track housing with passive solar orientation, and covered them with photovoltaic, the neighborhoods would be power plants. They could offer free HOAs and free electricity for the life of the house. Instead, we orient, organize and build for the maximum efficiency of a group of people who are only onsite for about 1 year (the developers) and then leave the people who live there for decades holding the bag.
> if developers built track housing with passive solar orientation
> Passive solar" orientation and insulation can prevent a HUGE amount of energy consumption.
In San Diego
In India, we have been using "Ductless Air-Source Heat Pumps" aka split AC units with 3,4,5 star energy ratings for decades. The more efficient ones come with dual inverter compressor which allows them to operate at lesser power (for lesser cooling) during long continuous operation periods (like sleeping at night).
Their application is however limited by climate: I've heated a room with a split AC last winter, but around here that is quite a bit of noise for quite a lot of time in the day/year. Having a heat pump warm up central heating water and use appropriate radiators or floor heating allows you to move the noisy bits outside the rooms you're in.
It's interesting how a sufficiently large local norm can affect perspective. I thought everyone had heat pumps for the longest time. I've rarely seen a building without them. I also live in the southeast where they're at their best.
Then this recent rise in popularity elsewhere dispelled that notion.
I have only heard of them on hacker news. Never heard of them im the wild.
I have both HVAC and a ducted heatpump for one part of the home. The biggest issue with the heatpump is that in the climate I live in there are times of year where you may have the heat on in the morning and the AC in the afternoon. Or you may leave and when you return you want to change the temperature. A furnace and an AC can do this rapidly. A heatpump takes time. It's more of a trickle of climatized air than a blast of it.
Also, I'd never want a ductless system as they look awful in a room.
They are the future though. Especially as new regulations go into effect by 2035. Sadly, many American manufactures haven't taken it seriously and are far behind the Asian companies like Daikin.
If you have the heat on in the morning and AC in the afternoon, your home is horribly under-insulated (or you are trying to keep in way too small a temperature range).
Old homes tend to not have any insulation. Parts of my house have modern insulation due to renovations/additions but other parts not so much. I wouldn't swap out the original windows and glass on the facade, for instance. And insulating it would probably be a destructive action as you need proper vapor barriers for insulation to not rot your home.
There are ceiling cassettes for mini-split systems that aren't nearly as much of an eyesore as the wall mount ones are.
Mini split systems can be used with ducts. All big venders sell heads which are specifically made to be connected to ducts. That way you get the best of both worlds and its also easy to retrofit to an existing (ducted) house.
This is a little known fact outside of the HVAC trades as everyone associates mini-split systems with the infamous wall-mounted indoor unit. I bought this LG unit[0] which I used some duct-foam board to build an adapter for and fanned out ductwork for that zone. People are amazed when I tell them this is a ducted mini split.
[0]: https://www.supplyhouse.com/LG-LDN127HV4-12000-BTU-Multi-F-C...
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Mine take maybe 2 minutes to switch from heating to cooling, or cooling to heating.
I’m saying the time it takes to change the temperature in the home, not the time to switch function.
I use a thermostat that can switch modes automatically to keep temps within a certain defined range. So I think that's why it's not a problem for me.
I was looking for a whole home heat pump and got some quotes that started at $27,000 for a home that is 1800 square feet. That price is a bit hard to swallow. I really don't want to just cool one or two rooms in the house.
Are you sure you aren't getting quotes for a ground-sourced (AKA geo) heat pump? We just installed a 4.5 ton (overkill for your sqft) 20 seer unit for $18000.
I got a very similar quote ($27k for ~2000sqft home) in seattle a few months ago.
Salesperson said there is excess demand for both labor and machinery for heat pump installations in the past few months. I wondered at the time to what extent this is a regional phenomenon (seattlites are nerds who like energy efficiency) vs. supply chain issues vs. a sales technique.
Interestingly, I learned that it will be too cold for heat pumps <10 days out of the year, so most people either keep their gas furnace as backup, or install an electric furnace for these rare days.
I had an AC unit installed just after the heat dome. Interestingly, while there was a lot of interest in people getting AC installed, few people were willing to put down 60% of the cost of the unit, which meant I was at the front of the line.
I was interested in doing an air-source heat pump (because hey, my furnace was 19 years old and would have to be replaced soon anyway), but due to the excessive cost, the payback time was figured to be something like 50 years. I would have loved to do that, but it just doesn't make sense. Instead, it was new AC unit + new natural gas furnace.
Nevermind ground-source, which would have been much more expensive.
Getting anything at all done in the Seattle area is super expensive. Not sure why. The rep is wrong about the too cold bit though, even just what's in stock at Lowe's is rated to well below record lows for the region.
Price gouging. I've gotten quotes for fence replacements, heat pumps, roofs, window restoration. There is nothing that isn't ridiculous price in my experience. Every company has the same, supply/demand and reference to pandemic statements to substantiate their costs.
It's also the case that demand is huge.
We have heatpumps in Seattle. They have integrated resistance heating (like baseboard heaters) for cold weather situations where the heatpump doesn't work well -- no need for a separate unit.
I'm in Seattle, my new-ish townhouse has a heat pump and it's never been too cold for it to be functional - it's worked hard some of the really cold+snowy days the last few years, but never to the point where it wasn't heating the house up perfectly fine.
I am not sure I would pay $27k for the whole install, but once it's there I've found it to be great. Extremely inexpensive to run and with all of Seattle's power being carbon-neutral, totally guilt free to set it to 68F at night during a hot summer day.
I am starting to wonder if there is just that much demand in the PNW. Maybe due to a large amount of older construction being built without ducting (baseboard heating)?
Putting mine here for reference as well: 12k for complete heat pump and air handler install using existing ductwork.
Let me guess - Greenwood? They came in 40-50% above all the other quotes I got.
I checked with them on an uncommon configuration (combo hydronic heat and hot water for the taps to replace the two gas units we have now) and their estimate was a lot of money but they were also the only company that seemed to have any idea what I was talking about. The reviews I read do suggest if you have an alternative it might cost less though:
https://freshchalk.com/greenwood-heating-air-conditioning-se...
That seems crazy high too though, I just got a 5 ton for a 2300 sq ft house with 12kw heat strips including duct work for 10k. The duct work was $3800.
I agree that seems expensive, but I wouldn't be totally shocked if a high-SEER, "name brand" unit with a pricey contractor could get that high. I had >100% cost variation for similar equipment between HVAC contractor quotes the last time I replaced a unit.
Yep, the price delta is definitely because of the high seer rating. That being said, we were quoted about the same price for a 16 seer unit from another contractor (McCarthy). It's definitely worth shopping around.
Nope, not ground-sourced.
May I ask where you are located (generally)?
Virginia
This kinda sounds like the installer had a queue of much larger / more lucrative projects to tackle, and quoted you a high price to get you to go away... or pay the ridiculous price and make it worth their time.
A decent heat pump sized for that square footage should cost well under $10k, and it's pretty unlikely your house would need so much work to install it that the labor involved could make up for the rest of that quote.
That price is absurd. Quoting an equivalent sized commercial installation from my company with union labor would be half that.
Being a Florida native, seeing an article titled "Heat Pumps [are] the Future of A/Cs" feels like it should have a ` [1973]` tacked on to the end of it. A heat pump is pretty much the only thing we use here, we just use them in reverse. Literally. Most residential units have a "reversing valve" that must be held open by a constant 24V in order to cool the air - the default mode is heating -- which is so smart to have a failure mode that causes your house to be heated in the summer to 95F while you sleep.
Anyway, my heat pump just stopped working this weekend, and its getting very hot in here.
A large part of it is that heat pumps only within the past decade became efficient enough to install in northern US climates, where temperatures are below freezing 4+ months of the year. It's relatively easy to design an air-source heat pump that will work efficiently down to freezing, it's much harder to design one that will work efficiently well below freezing, and frankly the A/C manufacturers who traditionally sold to the US market haven't really tried all that hard (they probably don't/didn't expect a large enough market to offset the development costs). It's newer market entrants from Asia that are really pushing the envelope of heat pump efficiency and making it feasible.
Air source heat pumps have worked well at -20c for a few decades now over her ein Finland. Not sure what type of chinesium grade heatpumps you have over there in the US.
Blame the building materials and shoddy aging homes, not just the pumps. -25c windchill whistled through cracks in my doors and windows at my last rental, and my feet would go numb if I forgot to wear slippers in the kitchen.
My electric furnace needed to be urgently replaced in the beginning of the winter, I'm quite happy that my new heat pump would default to heat...Half of the year :)
I live in a colder climate where heat pumps are not popular. After talking with a number of HVAC people about this I was surprised to learn that despite being very similar to an AC system in principle, in practice converting an AC system into a heat pump system doesn't make economic sense--you end up just ripping one out and installing the other.
I don't fully understand why this is the case, but I hope that there's something that can be done to improve it. I'd love it if I could drive my AC unit as a heater for 95% of the winter, resorting to natural gas only during in the extreme cases.
This persistent myth just needs to go away. People use heat pumps all over Scandinavia, including in the arctic circle. They are extremely popular there. They were early adopters of this technology there decades ago.
There are two popular varieties:
- Ground source heat pumps. Those work pretty much anywhere; just dig below the perma frost and you are good to go on the northern tip of Canada, Alaska, Norway, or wherever. Works great, ground temperatures tend to be very stable and it actually goes up the deeper you dig.
- Air source heat pumps. The expensive ones still work okish at extreme temperatures like -25-ish degrees C. Which is a reason these are actually more popular than ground sources even in places (e.g. most of Scandinavia) that reliably get such temperatures each winter.
Ditto Australia.
We've been using 'reverse-cycle air-conditioners' for heating in Australia for decades. I'm puzzled as to why there is any debate at all on their use for heating. A heat-pump is far more efficient for obtaining heat than direct resistive heating using electricity.
Many houses here use no other form of heating at all. And then at the press of a button, we get cooling in summer too. What's not to like?
* I also have a heat-pump condensing clothes dryer. The overall heat thrown out into the room is extremely low. The hot-air comes out the hot-side of the heat-pump to dry the clothes. The warm-moist air then passes over the cold coils, condensing out the water from the clothes and returning the heat to the cold-side of the heat pump which then pushes that heat-energy out the hot-side, producing more hot air to complete the cycle. I've had this Miele heat-pump condensing dryer going strong since 2009 - 14 years.
I've seen heat-pump base water heaters, but never a clothes drier. That sounds interesting. Now I have something new to research, thanks! Personally, I'm always curious why there isn't a more unified heat-exchanger system built into the structure of a house. HVAC, Water, Refrigerator, they all need to move heat from one place to another, why not work together?
I've tried to make the idea work in my head many times but my conclusion has been that I don't think there's quite enough co-incident demand for heating and cooling in the average house. For example, yes, I could generate all my domestic hot water from heat from air conditioning in summer, but in winter I need to be able to generate it plus heat the house, so I need enough capacity to generate that heat from the outside air when I'm not using air conditioning (so I don't save on not needing as much capacity), and the efficiency gains probably aren't worth the extra complexity.
For applications like commercial buildings, public swimming pools, industrial sites, etc. can (and increasingly do) definitely benefit from that kind of combination though.
I think the big issue is the different "tuning" for each heat pump system. For example, a heat pump water heater needs a different maximum temperature than an air conditioner, and has much different cycling behavior. This leads to very different design decisions, including refrigerant choice, pressure, compressor type, whether the refrigerant loop is even serviceable, etc. (Some appliances operate at a refrigerant pressure so high that they require being fully assembled at the factory, which would be a non-starter for a manifold system like we're discussing.)
I think this might eventually become a thing once science gets us far enough that there's an "obvious" refrigerant choice for most applications, but we definitely aren't there yet. There are hundreds of different kinds that perform better or worse in different applications.
AFAIK all of the big commercial systems that do multiple different types of heat transfer use water to do it, thus bypassing the entire refrigerant selection issue. Right now the most advanced we can do is VRF ("Variable Refrigerant Flow") systems that can individually select air handlers for cooling or heating (i.e. move the heat from one room to another). These are still commercial units and not really available for residential installs.
There’s a reason new houses get built with geo based heat pumps in Finland.
This enables your hot water heater to use the same circuit to heat water - that decreases your hot water bill to around a third, even in winter as the necessary heat isn’t taken from the indoor air but from the ground.
Yeah, as a Kiwi, watching all the debate happening here is just super weird.
Meanwhile, I'm annoyed that heat pumps that dump the waste heat into the hot water cylinder aren't standard.
It's just the Yanks that have subsidised natural gas in many states, and a messed up energy infrastructure that gives electricity prices in the same range as what we have in Europe while being at war.
I was trying to find heat pump adoption rates for Europe and US.
Seems like its still pretty low in Europe outside some northern countries. Germany is less than 2000/100000 people.
https://www.theecoexperts.co.uk/heat-pumps/top-countries
Meanwhile this link says US has a 15% adoption rate across all income groups. That seems higher than I expected.
https://energypost.eu/u-s-heat-pump-adoption-is-evenly-sprea...
Is there a better source on heat pump adoption rate in Europe and US?
Not a source, but it's more common to have heat pumps in the southern States where winters aren't that bad. I'm born and raised in Arizona and they seemed to be common in houses after the 1973 energy crisis. My grandparents house in Tempe, AZ (was built in like 1950's) did no have one. A house I purchased in central North Carolina had a heat pump. I'm now around Washington DC area in Virginia, and we has gas. I think a simple explanation is that natural gas is almost a by product (certainly from landfills, which is how most USA disposes of trash) and is very cost efficient. Also the energy crisis changed the outlook of house building. I hope that helps explain it some, sorry I don't have any concrete facts I'm typing on a small keyboard.
Yes. Although I have noticed that some people here in Australia go from the belief that "air conditioners use a lot of electricity" so therefore have the misconception a (resistive) electric heater must be cheaper to use than the reverse cycle AC (heat pump). So there is a bit of an education gap even here where they are quite ubiquitous!
I also do want to get a heat pump dryer (it's next on the list after my recently installed heat pumper hot water system), but I don't have quite enough space in the laundry and apart from two or three wet weeks a year I'd mostly only use it to fluff up towels (which is why I don't have a dryer at all at the moment)...
> have the misconception a (resistive) electric heater must be cheaper to use than the reverse cycle AC
You'd think costs would educate. Do people not talk about living expenses much?
Electrical bills come every three months. ALL electricity use is lumped together. So it's a bit hard to disect out what each usage-type is costing, unless you use one of those meters and study up average use over a period. Even then, some things like water heating and even aircons, are directly wired into the mains switchboard, so you would need an electrician to separate out those circuits for measuring. So it just doesn't happen.
Heat pump dryer system is state of the art for efficiency. I saw some complains by American that it takes too long time for drying, but I don't know why they need to dry things so frequently.
I was thinking about this anomaly yesterday. Then I remembered that most US electrical outlets are at 110 Volts instead of the more usual world-wide standard of 220 volts. So most stuff in the US is under-powered by EU or Australian standards. Being under-powered, it would take longer to dry your clothes.
(That's also why they don't seem to use electric kettles in the US commonly as is normal in 220 volt countries)
I like mine, but it has a small capacity compared to a standard dryer, and we find that over time water slowly condenses inside of it, so we have to drain it a couple times a year to stop it from shorting its control panel. Not 100% if it's design flaw, micro leak, or what. 8 or 9 year old LG unit I think.
If I’m doing 3 loads of laundry for the family, I don’t want a 2.5-3 hour dry cycle to make laundry take all day (or make me do laundry of half the days of the week).
I don’t want a 2.5-3 hour dry cycle
??? That's excessively long. Our heat-pump dryer takes about 20-30 minutes to do one of our loads.* The dryer invariably ends up waiting for the washer to finish.
* Our loads aren't excessively tight in the machine. You have to allow room for the clothes to tumble loosely thus allowing lots of surface area for evaporation.
I quickly googled for “how long does a heat pump dryer cycle take” and got several answers in the 2.5-3 hour range, which is long enough to provoke complaints.
Obviously, if every heat pump dryer took 20-30 minutes, you would not hear complaints about that (that’s much faster than my gas dryer).
Power-input. US dryers would typically work on 110 volts mains. Those similar dryers in the EU or Australia are working on 220 volts mains. Took me a while to click on why the great differences in working-times. 15 amps wiring in the US means 1650 watts, the same wiring in EU is 3300 watts.
That's not it. Electric dryers in the US are overwhelmingly 240V and on a 30A breaker. At 80% of rated, that's 5.7kW available. (Gas dryers here are typically on a 120V, 15A circuit.)
Every heat pump dryer I looked at on the home center's website is 240V. (Edit: I found one Miele on another home center that was a 15A@120V.)
The myth exists because the US is probably 10-20 years behind Europe and China in terms of HVAC and insulation technology. I recently had some reasonably high efficiency heat pumps installed at my house, and I’ve been very unhappy with the low temperature performance. It doesn’t even get very cold here—rarely below 5F (-15C) and a record low of -8F (-22C). The heat pumps I got (recommended by the well-regarded local HVAC company) operate at just 40% of rated capacity at 0F.[1] Meanwhile, Chinese and Japanese-made inverter driven heat pumps will happily go down to -5F at 100% of rated capacity, and -22F (-30C) at 80% of rated capacity.
[1] You can of course get a much larger heat pump to compensate, but that leaves the unit way over-sized for cooling loads.
I recently saw a transport nerd claim that US and Canadian (though interestingly not Mexican) busses were substantially and objectively worse in build and ride quality than European busses, even when they share the same engine components.
Which I guess similarly explains a lot of weird conversations and people talking past each other where busses are concerned.
In my local market, if you ask an installer for a heat pump, you get something from Japan or Korea. I’ve never encountered an American unit.
(I’m referring to normal air-to-refrigerant-to-air heat pumps. I know of a really weird system that is thoroughly American and an utter pain in the arse to replace because it’s specialized and undocumented. It’s quite loud, too, because it’s single-speed, and that single speed is waaaaay too high.)
The Asian brands make products for the US market—often through subsidiaries that were originally US companies, such as Goodman and Amana. Basically stuff that complies with US codes and standards, and that US HVAC installers can fix without learning anything new. Daikin makes a ton of stuff they don’t sell in the US. Owens Corning makes high density fiberglass batts you can buy in Canada but not in the US.
Trane and Carrier are both US based and do heat pumps. They are more expensive than Mitsubishi or Daikin though.
Some (all?) Trane heat pump models are re-branded Mitsubishi units.[0] Not sure about Carrier.
Sounds like the units you are describing don't have an efficient (read 'big enough') heat-exchanger which is why they aren't being effective in not-so-low temperatures. The temperature of the cold-side should not be below outside ambient temperatures if the heat exchanger coils are sufficient.
In other words heat-energy should be going into cold side of the heat-pump (even at a low temperatures) at the same rate as it is coming out the hot-side at high temperatures. Reduce the heat in, and you will reduce the heat out.
It’s a typical size for a heat pump in a US home: https://www.amana-hac.com/products/heat-pumps/18-seer-aszc18...
My understanding is that improved low temperature performance has something to do with varying the amount of refrigerant in the loop: https://www.mitsubishicomfort.com/articles/keep-warm-this-wi...
Sounds like they undersized your installation in order to quote you a lower price. The efficiencies of heat pumps are well documented as are the weather patterns in your area. So, they should/could have known better.
Two solutions to this problem:
1) get a bigger/better heat pump.
2) improve you building insulation and figure out where you are losing energy.
Can't you get backup heating in addition to a heat pump for the coldest days?
I live in FL and we have a backup resistive heating element that kicks in as needed. Mostly only comes on a few days in the year or for short bursts when there's a cold snap that the heat pump can't keep up with.
This is fine until everyone in your neighborhood has one and it causes a brown out. (Peak amperage for the heating strips on my heat pump are three times as high as for the heat pump itself at maximum cooling load.)
You can upgrade your home electrical service and the power company handles all that for you.
Air source heat pumps are super popular in Poland too, this winter it was about -20C for couple weeks straight and not had any problems, toasty house without any issues. The key is that the heat pump exchanger really needs to be huge(ours is taller than a person) to get the heat out of the air.
I've been on zoom calls with two separate co-workers who are all bundled up because their heat pump can't handle the weather. It doesn't mean that the technology is inadequate in principle--probably their systems have some problem that competent HVAC installers know how to avoid.
But its an unfortunate fact that there are places in the US where installers that recommend heat pumps can't be found for 100 miles. It doesn't really matter if I'm technically correct about the merits of the tech in principle--if I can't find somebody to fix my system and my pipes start exploding, I've still made the wrong decision.
Also, heavy snows cause power outages in places where tree limbs fall on overhead lines. If gas outages happen... well I've never experienced one. Sure, if I lived in Norway I'd have a government that cares about updated infrastructure and I wouldn't have these problems, but since I don't, I do.
Given my local constraints, a dual-fuel system sounds pretty great.
Gas outages happened at a large scale in Texas when they were struggling with a bit of cold weather. When they needed it the most, it failed them. Coal plants also struggled. Both had challenges with supply of fuel and cooling water being disrupted. That kind of systemic infrastructure failures is on the rise in the US. There are all sorts of reasons why governance just isn't great in the US. But the reality indeed is that things are unlikely to improve on that front.
Which are all good reasons why the market for domestic solar, batteries, and heat pumps is so hot right now. The US is no exception to this.
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Properly designed heat pump system includes backup for the coldest days - usually direct electric heating.
Most houses in Finland have a (decent) fireplace for heating in case of an electric outage.
> heavy snows cause power outages in places where tree limbs fall on overhead lines. If gas outages happen... well I've never experienced one.
If I lose power, my gas boiler does me no good. A gas boiler will use pumps (and likely a power vent). A gas furnace will use a fan and a power vent.
It's a lot easier to keep a gas furnace running on a generator for an extended period of time than a heat pump.
There are power outages in Norway too - though there are typically years between incidents, and years and years between incidents lasting a day instead of hours (with the exception of certain avalanche-prone areas where this happens much more often than people would like). So my home has a backup system - as do most houses. And that's a wood heater. But my house is so well insulated that it takes a day even in the coldest of winter before I actually need to use it if this happens. Newer houses are also quite much better than mine in this respect.
I switched in New England when my freon system hit end of life. I wouldn’t recommend doing it beforehand, but as a replacement it’s been incredible. All the ductwork and infrastructure largely remained the same. Pulled out the furnace, evaporator coils, and compressor of course.
It cools better than the old system, and the fact that it runs longer instead of in short bursts means it regulates humidity way better too.
For heat we did go dual fuel, which means the backup heating element uses gas, since we already had the line. This works really well in a cold snap where temps drop well below freezing.
Fellow New Englander here. We had a 4 unit heat pump system installed a few years ago, replacing a bunch of window air conditioners. Not only is it a vast improvement over the window ACs in terms of ease of use, sound levels, comfort, and electricity use, it has become our default heat source in the winter as well, greatly reducing our natural gas bills.
There's no reason you couldn't just switch a couple valves out in your AC and perhaps change the refrigerant to make it into a serviceable heat pump. However, you'd need to retrofit controls/electronics, which I don't think most HVAC technicians would know how to do. It's also not advisable to attempt to DIY something like this because it is very easy to accidentally vent the refrigerant, which is a very potent greenhouse gas.
Right. It's a problem best confronted by the AC manufacturer. Except they have no incentive to do so (because if they don't, they get to sell an entirely separate heat pump down the line). Which means it's perhaps a problem for the regulator.
There are tax breaks involved with installing "energy star" rated equipment. Perhaps we ought to start witholding the star from AC units that are not easy to convert to heat pumps (and from thermostats, etc, which are not ready to handle the conversion).
I think that would be an excellent regulatory solution. You should write to your representatives. Since heat pumps are getting a lot of regulatory attention, it might actually get considered.
By the time you do that, you might as well also put in a variable speed compressor and a variable speed fan, at which point there’s not much left.
(Seriously, where I live, you will likely pay $1k or slightly more to drain and refill the refrigerant. The hardware for an entire modern heat pump, indoor and outdoor components, is maybe $3-4k. Is it really worth it to drain an old existing unit, cut the pipes, add a reversing valve, retrofit in the controls, pressure test everything, deal with the fact that the outdoor unit (formerly the condenser coil) will start producing copious amounts of condensate that the manufacturer and installer did not anticipate, and refill the system?)
This is because HVAC companies wildly overcharge. It does not take $1,000 worth of labor to drain and refill refrigerant, but it does take a qualified technician, and there are not enough of those.
That’s absolutely true. But the same problem would exist, much worse, if everyone started modifying their old A/C systems to turn them into heat pumps.
To add to the list of why this whole idea seems dubious: a conventional air conditioner operates with its evaporator coil at a balmy 50F or so. If you reverse it, the outdoor coil will become the evaporator, and it will operate below freezing if it’s cold out (even if the outdoor temperature is a bit above freezing). As a result, condensate can form and freeze on the coil.
This is entirely manageable (any modern heat pump can operate in decently chilly conditions, and heat pumps equipped for low temperature operation can operate in very cold conditions), but I expect that at least some engineering is involved.
I live some 5 hours north of Montreal, we have few days at -40C and wall radiators (not sure about the name) are needed, but for most of the winter days we use the heat pump to heat the house (-21C and up). Some members in my family work in AC/Refrigeration industry and all of them have thermo pumps, which make economic and ecologic sense. On the other side I don't know about AC/heat pump replacements as it's not common to have AC for the just a handful of days that could be very hot.
Colder climate is exactly where you want to use heat pumps. The numbers for Norway in 2022 (https://www.novap.no/om-varmepumper) is 58% of Norwegian homes (houses) have a heat pump installed, 34% in service industries, 8% in other industries. For homes air-to-air dominates (more than 90%). And since then this has just increased even more (and older heat pumps are being replaced with newer and better ones as well).
As an aside, many have commented on the claim that heat pumps make more sense with a well insulated building, arguing that it should be the other way around. The reason that you do want a well insulated building is simply that air-to-air heat pumps are limited to typically less than around 8kW heating capacity, and with a well insulated house you can heat a large area with that, with bad insulation you can't, and you would need a much more expensive type - typically not those sold to home owners (or buy several pumps, exploding the costs). In addition to that, a heat pump is more efficient when it doesn't have to run at maximum capacity. The heat pumps sold in the Nordic countries are typically around $3000 including installation. And they're highly efficient.
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The thing is (especially where I live) I'd still need a gas furnace. We regularly see -20F to -40F in the winter. While the 95% scenario sounds great, in practice still needing gas means we still need all the gas infrastructure. From my understanding natural gas burns pretty clean. The problem is leaks in infrastructure and drilling, which isn't going away because I buy a heat pump.
Although natural gas is "clean" compared to, say, coal, the advantage of a heat pump is that it uses less total energy than natural gas. That means it would be more efficient to run a heat pump off a natural gas power plant than to burn natural gas to heat your home directly.
Where I live, you can bank solar credits. If you cash them out you get the "wholesale" energy price for them (much lower), but if you spend them on electricity then you've avoided paying full price for that electricity. So if your system produces more than you consume, you've got this free energy budget to spend--a budget that applies to heat pumps and not to gas furnaces.
People's AC summertime electric bills regularly get into triple-digits - it's not uncommon to hear someone with a moderately sized home having a $200-400 electric bill in the summertime.
However, even in the midst of winter, gas heating bills rarely climb above $100 monthly.
What am I missing here? It seems a heatpump, while more efficient, will cost significantly more to operate. Natural Gas is cheap... and clean enough.
It's actually difficult to say what the cost would be if everyone switched over. The reason is that natural gas is subsidized, both on the production side (at least in the US, which wants energy security) and on the consumption side (because it's politically unpopular to let people freeze to death). Of course, electricity prices are also affected by subsidies. Figuring out the true operating prices would require some research. However, it remains true that, in terms of greenhouse gas emissions, it is usually preferable to heat a home with a heat pump than by burning gas directly (there exists a temperature below which any given unit will become less efficient than burning gas, but unless you live in a place where this temperature is common then heat pumps will still come out on top (and the fact that residential gas lines are notoriously leaky and basically just venting nonstop into the atmosphere makes the calculation even more favorable)).
It seems to me, there is no future where a heatpump can be the only source of in-home heating then.
1) Natural Gas is vastly cheaper in most/all of the US.
2) Homes still require an alternative heating source when temperatures drop to low levels (coincidentally when people need heating the most).
So, even if a heatpump is technically more efficient in terms of emissions, the technology does not solve all of the problems it's attempting to replace. Additionally, Natural Gas is vastly more clean in terms of emissions than some other alternatives still used around the country.
There's no way the average home is going to stomach 2-4x more heating expenses on average without some real tangible benefit (hand-wavy emissions numbers don't factor into the average homeowner's decision making).
I must be missing something here...
> It seems to me, there is no future where a heatpump can be the only source of in-home heating then. > > 1) Natural Gas is vastly cheaper in most/all of the US. > > 2) Homes still require an alternative heating source when temperatures drop to low levels (coincidentally when people need heating the most).
> ... > I must be missing something here...
Yes you are, your natural gas subsidized, i.e. government handout, i.e. you're not paying the real market cost.
Second, heat pumps do not have issues with cold temps, unless you're at like -40c. They're used all over the nordic countries - including above the arctic circle.
Your energy grid is shit, which is why your electricity price is so high.
> Yes you are, your natural gas subsidized, i.e. government handout, i.e. you're not paying the real market cost.
> Your energy grid is shit, which is why your electricity price is so high.
Adding a heatpump solves this issue, or makes it worse?
Heat pumps power consumption can be modulated by energy providers and improve grid power stability.
In Germany you get way cheaper electricity prices if you allow this.
I am not aware of any such system in the US.
What do you mean by "modulate"? Your utility provider decides how much heat your home gets? That's a very strange concept.
No, they decide how many energy the heat pump currently uses for heating.
That means they control how much heat you get. Otherwise, they would always run in a more efficient/lower-energy demand mode... think about it.
Its only for a restricted time frame
Heat pumps might work at -40c, but all the efficiency gains are lost and it's going to cost a fortune.
The best one reaches 1:1 when approaching -35C, which means that they're as efficient as resistive heaters. So you save nothing in electricity costs, and if all your days are that cold then the $3000 you invested in the heat pump is wasted (that's how much a quality pump with installation will cost you in the Nordic countries - it seems to be much more expensive in North America, at least that's what the comments appear to indicate).
If you have warmer days now and then then you'll start saving money, and eventually it'll pay for itself. Where I live (cold winters), the cost was covered in only two years.
2-4x seems like a stretch, and would only apply in areas with very high electric rates. My last house was heated with a builder-grade heat pump (HSPF around 8), and my winter electric bills were around $150-200/mo. My current house has natural gas heat, and similar level of appliances/EVs/lighting, and winter bills electric bills are around $100/mo. This is the same town and the electric rate didn’t change, so the net cost of heating my old house with a heat pump was only $50-$100/mo. Meanwhile my winter gas bill in this house, subtracting baseline summer usage, runs more than that.
The only backup heat I had with the heat pump was electric resistance heat, which I needed to use only once or twice each winter for a few hours at a time.
You can also use resistive heating (like baseboard heating or space heaters) as a backup for the heat pump when it's too cold out. They're expensive to run off the grid, but if you have solar power and battery storage (for operation at night), they're essentially "free".
Obviously you wouldn't install solar panels and a battery just for this, otherwise it's very much not free, and probably a lot more expensive than burning gas. But if you already have the solar+battery install, and have enough capacity, it could even be cheaper to operate than a gas furnace.
You’re talking about the future but only consider the present. You’re one government decision from your calculation to have an opposite result. Estimating probability of any such decision (ban on fracking, tax incentives, etc) is the hard part.
I'm with you here. I replaced a gas water heater with a hybrid water pump and I'm paying more for my troubles. The thing is, I do plan on installing PV panels in a few years--I can't generate my own gas so once I make that happen, I'll be a happy camper.
That was my plan; install solar panels and then slowly switch things from gas to electric as they need replacement. Unfortunately solar installer I was in contract with canceled on me for seemingly-bogus reasons, and I didn't have time to find a new one before California's new, unfavorable net metering rules went into effect.
Most hybrid water pump heaters do not fully use their heat pump by default - their should be an "Eco" or "heat pump only" setting somewhere on your device which will make it much more efficient.
I'm fairly certain we're near - or even past - the point where burning natural gas to run a generator to power a heat pump will use less gas than burning the gas directly for heat.
Perhaps you live in a warm climate? A heatpump (or heatpump + gas for a very cold climate) should cost always cost less than gas
Replaced our entire system (furnace, a/c) mid last year. Heat pump with backup oil for colder days.
We cut the amount of gallons we used by over 50% compared to last year. Sure the oil infrastructure is needed to get it delivered (I wish we didn't need it) but I'm very happy that our heating (oil+electricity) bills are so much lower, even with the increased oil prices.
We went with a mid-range system but now I kind of wish we sprung for the "Cadillac" version.
I suppose this would be true if gas is expensive where you live. It's really cheap here, our heating bill is like $80/mo in the coldest of months for a 3k sq ft house. A heat pump even with the efficiency gains would be on par with that (unless we jumped into solar, which I have considered).
You need a backup heat source, but it doesn't necessarily mean you need full infrastructure of gas lines, ducting, and gas furnace. You could have an electric backup connected to ducted heat pump (e.g., non-efficient, pure electric) or could use electric strip heating, electric portable heaters, wood stoves, etc.
We have electric baseboard. It would cost hundreds more per month to utilize something like that instead of gas when it is -30F. In fact if we just leave it on over night a single time we notice it on our bill.
They make heat pumps with backup gas systems now.
Converting an A/C to a heat pump is a bit like upgrading an old Lenovo laptop to a modern CPU. It’s surely doable, and the parts are unlikely to be terribly expensive, but as a practical matter it’s pretty specialized and no one does it.
What you do is wait for the A/C to hit end of life (or end of efficient life if new systems are enough more efficient) and replace it outright.
(I once got a quote, in an expensive market, to add an A/C to an existing furnace and, separately, to remove the furnace and add a three-head multi-split heat pump. The two quotes were almost the same price. The equipment is not especially expensive.)
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It's a $300 part that allows swapping the direction of heat flow. This tiny upfront cost is enough to block tons of good practice.
Nate the House Whisperer is a guy who has been trying to build a new generation of HVAC practice, and though he says he's usually a libertarian, he advocates for adding a tax to AC-only units that would eliminate this price difference (or some similar practice, I forget the exact details...)
These gradient comfort guys want $5000 for an 8000 btu unit with a total weight of $150 pounds. Compressor and heat exhaust hand outside. Evaporator and fan/control hang inside, It has a SEER rating of 10. There are dozens of minisplits for $1000 that have a SEER from 19-24. I can see no reason why a close coupled mini split with a 1" armored electrical/freon joint could not be made. This is what a gradient comfort is WTF $5000 https://www.gradientcomfort.com/products/gradient-window-hea...
This seems to be a much more reasonable unit, 10,000 BTU, does both heating and cooling via a heat pump, and it costs $700, although there are a lot of negative reviews:
https://www.amazon.com/dp/B09ZCZSSV8
$5000 is ridiculous for the Gradient Comfort 8000BTU window unit. The Soleus is the only other heat pump window unit I've seen for sale. Midea makes some A/C's that are more efficient because they use an inverter, but they don't do heating. There seems to be a market failure here, given that a bidirectional heat pump shouldn't cost much more than an air conditioner you'd think everyone would prefer a heat pump, especially since it would lower cooling costs and can do lower cost heating in the winter. But nobody is selling them at reasonable cost and quality. They could include a heat exchanger also to bring in fresh air without losing energy. But nobody makes such a thing. Maybe the barriers to entry in this market are high for some reason? Window air conditioners have always kind of sucked (too noisy, encourage mold, uneven distribution of cold, crummy temperature control). I wonder why. It seems wrong.
This unit is designed differently, blocking more of the view, but lets the window close: https://www.amazon.com/Midea-Inverter-Conditioner-Flexibilit...
People are happy with this unit in NYC for tiny pre-war construction units that can't use traditional A/C for reasons.
The other unit you link appears to be sold under a variety of brands, look at the comparable products and the button configurations, in all of them the blue light on right is a bit offset upwards:
https://www.amazon.com/R-W-FLAME-Conditioners-U-Shaped-Condi...
This is not unusual. Almost all these compressor-based mechanical boxes, from A/Cs to refrigerators, low end to high end, are made by the same 3 mega companies and white labeled by even the "best" known brands.
The Midea model you linked does not supply heat, but this Midea model does seem to have a heat pump that can supply heat:
https://www.amazon.com/Midea-Cooling-Inverter-Window-Conditi...
But the page also says: "NOTE: heat pump function will not work if outside temp is 41°F or below."
The R-W-FLAME unit has about as many bad reviews as the one I linked. Maybe the reason for the lack of products/competition is as you say they "are made by the same 3 mega companies".
It's that cheap because it's garbage. All the 1-star reviews (26% of all reviews) I looked at said various variations on the unit failing after some small number of months, and the return/replacement process is awful.
Seems like the manufacturer just makes junk and hopes they can still keep the money by making it hard to return.
Have you ever looked for a product and found that ALL of the brands get poor reviews? Air conditioners are kind of like that, maybe half of them get a lot of poor reviews. Somehow air conditioners have seen a race to the bottom in terms of quality and features. The basic technology has also not changed in decades. Seems ripe for disruption. The Midea air conditioners are at least more efficient. There are a lot of commonly known problems with the basic design of window air conditioners though (uneven air distribution, creates drafts, mold, noise, temperature control). Maybe those problems are just too difficult to figure out? Maybe it's a problem of expectations, air conditioners have always had the same prices and features so no one will pay any more, even for a better product?
In Australia we call these "Reverse Cycle" Air-conditioners.
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Well this was an oddly terrifying introductory paragraph for an IEEE article:
"... half of Phoenix residents are at risk of an emergency room visit or worse if their electricity fails during a future heat wave, according to a recent study. Air conditioning is what keeps people there comfortable—and alive—a growing fraction of the year. The extreme heat already kills hundreds of Phoenix-area residents every year, a number that went up by 25 percent from 2021 to 2022."
I've read a few times that the population of the entire US south only really started to grow in earnest once AC was invented.
Ah, here's an article: https://www.nytimes.com/2017/08/04/upshot/the-all-conquering...
It's pretty crazy because growing up in central/northern Alberta, I never even really encountered air conditioning until I was into my early 20s and moved to southern Ontario (where living without it would be complete hell in the summer, hot humid disgusting "I feel like I'm being smothered in someone's armpit" summers). Our cars never had it and our houses certainly didn't need it; just an open window. Summers were mild and the heat when it came was a dry heat.
But now when I go home to visit there, A/C is everywhere there, and it's frankly needed; the last summer I spent time out at my parents west of Edmonton there were multiple days in a row over 30C and it was frankly quite hellish and them having a ground source heat pump that cooled the house was a godsend. Just the 2-3C difference in peak temperatures from the 80s til now is enough to push it over the edge into new territory.
I've likewise read arguments that AC is linked to the substantial economic growth in the second half of the 20th century, in regions like southern France, southern Japan, and the southern United States. All regions that historically lagged economically behind their culturally and economically similar more northern counterpart regions. Hard to say how much of a factor, but there has to be some truth to it: just imagine productivity in a Texas factory at 40 °C and 90% humidity vs. 25 °C and 50% humidity.
The man credited with making Singapore the powerhouse it is today has also been adamant that without Air Conditioning, tropical countries couldn’t develop https://www.vox.com/2015/3/23/8278085/singapore-lee-kuan-yew...
Luckily, the local grid here in AZ is fairly robust, probably one of the best in the US. During the 3 years I lived in DC area, I probably had 3 or 4 power outages due to weather (ranging from a couple hours to multiple days).
In the 30+ years I have lived in Arizona, I have experienced probably 2 outages, lasting a total of a few hours (one was when a car hit a transformer, the other was when a microburst knocked a bunch of aging poles down).
The last outage I had was like 6-8 years ago.
I would imagine solar panels would be a good investment in a climate like this.
There is actually efficiency issues with the high heat... but they do help offset the AC requirements, so overall even if the efficiency is down 20-40% because of heat, you require potentially 20-50% less A/C because it shades the roof.
Or a solar boiler connected a refrigerant compressor. The hotter it gets the more cooling power you have. Steam punk for the 21st century.
It raises the question of if we should deploy 'emergency coolers' - perhaps single-use barrels of some chemical that gets cold when a pull-tab is pulled. To be a workable solution, it needs to be more reliable/cheaper/more effective than just a regular gasoline generator powering a regular aircon unit.
After a flood/hurricane/nuclear strike, they would provide enough coolness to keep people alive for a few days.
Water can be used for this purpose, and swamp coolers are something that can be pretty trivially implemented by people in relatively dry areas. For very humid places you generally need energy input for cooling.
I believe the straightforward answer is to dig a hole. But it would certainly be interesting to calculate exactly how much cooling capacity you could get out of one or two 55 gallon drums of some endothermic precursors. Bonus points for being easily reversible when the electricity comes back on (like those sodium acetate heating packs).
Sure, but it can happen anywhere. I was just reading yesterday about a person who died in Portland of heat during the dome.
Same with cold weather, if the gas/electric goes out during the winter. There's really only a few places one can live with moderate enough weather to avoid those scenarios.
>>Same with cold weather,
I 100% disagree with this...
Heat is made by everything, waste heat is a byproduct of all modern things, and there are TONS of easy low cost ways to make heat even it is just as simple as burning something.
Also the body makes head naturally so adding layers to trap this heat does not require continual inputs from an outside resource
Cooling on the other hand is MUCH harder, and electricity is really the only avenue to make cooling. Even if you say use ICE, well that Ice was made at some point by a freezer running on Electricity
IMO hot climate is MUCH MUCH more dangerous than cold, which is why I choose to live in an area where there are only 1 or 2 months of even remotely hot climate.
As I told my last HVAC... Heat I can make 100 ways... Cooling I need central air for...
For a young/healthy person, sure. But these aren't generally the at risk people in the first place.
I grew up around the 38N parallel, gross enough to get too hot in the summer and too cold in the winter. Every winter people froze to death, just the same.
It's not as bad as Phoenix percentage wise, but it's still a risk in the vast majority of places that people in the US live.
Of course people can and do die from cold, that was never my claim
My Claim is providing people with emergency heat is FAR FAR FAR FAR easier and cheaper than providing people with emergency cooling.
Do "at risk" people die in the north from the cold, absolutely but I am not sure how that means the cold is worse
As it stands right now, just from my daily activities my waste heat in my home makes my home about 10-15 degrees above ambient. Meaning in the winter if my target temp is 65deg, it would have to be 50 degrees or colder outside before I would even think about running my heat.
In the winter time that means my AC is working hard to not only combat the outside temp but the internal waste heat from computers, cooking, TV's, humans, etc.
> Cooling on the other hand is MUCH harder, and electricity is really the only avenue to make cooling.
Gas-powered fridges and coolers have existed for about two hundred years and are still a normal technology today - often used for camping and off-grid life.
Here's a whole bunch of propane fridges for your viewing pleasure: https://bensdiscountsupply.com/collections/propane-refrigera...
And yet the propane stove, designed to heat, is about 1,000 times more common.*
* citation needed.
Eh, it is much much easier to keep warm when it's -40 outdoors than it is to keep cool when its 120+ outside.
Unless you have a terribly insulated shelter, blankets, coats, and friends will keep you warm enough to the extent that unless you are not really capable of taking basic care of yourself, you're not dying of the cold when your heat goes out. You can always do more insulation, and you only need so much for your body to keep you warm.
With heat though you run out of things to do.
There is a difference between an impaired person or a person doing something unwise dies of the heat or cold... and there being an environment where there's nothing a healthy adult can do to survive without powered heating/cooling.
Part of this is because we build houses that are terribly suited for warm climates.
I used to work in the Middle East, and their traditional structures with central pool and windcatcher/chimney design remained quite livable even when it was over 45°C outside, with zero active cooling.
And that's why you see fireplaces/stoves in a lot of houses in the northeast, even if they have gas/electric heat.
what?
do you really not see a difference between a place where the event is much more likely to happen for a much longer % of the time than another place where the same event is much less likely to occur?
Half of Phoenix vs A person in Portland.
It seems like there’s an important scale issue there. So the risk isn’t really the same everywhere.
Good point on the scale. However, Phoenix is also a retirement destination so you're looking at a larger portion of the population being susceptible to heat waves.
> Phoenix is also a retirement destination
People who retire there most likely go up to Flagstaff in the summer, or further north.
Or they just have good A/C.
Time to start calling it Life Support Systems
I've only ever visited Phoenix but when I did it was mid July and being outside genuinely did not feel hospitable to human life. That statement doesn't surprise me at all. Unless you're employed in, I dunno, the solar power industry I really feel like you shouldn't be living there. It should be like living on an oil rig.
Do you think people shouldn't be living in Chicago (or most of Canada and the US midwest for that matter) because without heating it's just completely inhospitable to human life during the winter?
Or pretty much all Australian cities in summer?
I haven't formed an opinion on the matter yet, but I do think there's a large difference between it being too cold and too hot.
If I'm too cold and my power goes out I have a lot of options to survive. I can put on more clothes, get under a blanket, light my furniture on fire, etc
If I'm too hot and my power goes out, I die. Once the wet bulb temperature gets above a certain level in shade, there's nothing that can be done to stop me from dying except Air Conditioning.
Wet bulb isn’t an issue in notoriously dry Phoenix. If your power goes out in Phoenix you jump in a pool.
What? That doesn't make any sense at all. The whole point of wet bulb temperature is to adjust for humidity. Also only 33% of Phoenix homes have a pool. Using a pool as a solution to prevent people from dying is a "let them eat cake" idea
It's not an issue because Phoenix is always dry, so the wet bulb temperature is always low.
The wet bulb temperature of Phoenix still gets very high. Last July, there was an average wet bulb temperature of 73 degrees Fahrenheit. 95 degrees will kill a healthy human, it takes much less to kill a vulnerable person or someone performing manual labor. Climate change is only going to raise that number.
Like the other commenter who already corrected you, it makes perfect sense if you actually understand how wet bulb works, here’s a calculator for you: https://www.omnicalculator.com/physics/wet-bulb
Hint: Phoenix is at 17% humidity today, even their all time high of 122 doesn’t push the wet bulb temp out of the safe range.
I understand how wet bulb temperature works just fine. You didn't need to write a snarky response to engage in this discussion.
Now include climate change raising the temperature and changing the length and severity of monsoon season, continued development raising the heat island effect.
It doesn't matter what the average wet bulb temperature over the entire coty over a long period of time. It matters what the peak wet bulb temperature is for significant number of vulnerable people. The wet bulb temperature only has to get very high once to kill a large swath of people.
I understand just fine the wet bulb temperature has been within safe levels for the vast majority of people so far. My concern is about the future.
The entire south is at a much higher risk from wet bulb: https://www.iflscience.com/southern-us-reaches-dangerous-wet... so my point still stands, wet bulb isn’t an issue in Phoenix.
You didn't respond to any of my points at all. One area being at risk of something doesn't lower the risk in a different area.
Relying on a coat for survival is very different from relying on an HVAC system. One has no moving parts, requires no external inputs, and is routinely handed out for free to those who can’t afford them.
People have lived in the midwest since long, long before modern heating.
Heating is considerably more energy efficient than having to run ACs all over the place. And if you need to go outside when it's cold you can: you add layers of clothing.
In Arizona, in the middle of summer, you could be buck naked and you'd still overheat (and get burnt, to boot).
Heating takes considerably more energy than cooling. Especially since most heating is done with natural gas, if homes were heated with a heat pump it would already 2-4x more efficient. Then if you look at the temperature delta between outside and room temp, the cold climates have a much larger difference. Taking 100 degree air down to 75 takes less energy than bring 20 degree air up to 65.
> Heating is considerably more energy efficient than having to run ACs all over the place.
That's actually incorrect. Heating takes considerably more energy.
When you're cooling you're looking at a temperature delta of at most 20 degrees C/45 degrees F between outside and inside. When you're heating, it can be easily be twice that. Or even more, in parts of Canada or the Great Lakes states.
Air conditioning is a heat pump and can achieve up to 300% efficiency. Whereas most houses in cold climates use furnaces, which have at most 98% efficiency.
Now that we have more efficient cold-climate heat pumps all of this may gradually change. But as of right now, what you're saying is wrong.
Heating under usual winter conditions would consume more energy than cooling under practical conditions. Yes.
But that's very different than claiming than cooling is more efficient than heating. In A/Cs the ratio of energy (in the form of heat) removed to energy consumed is very low, around 10-15%.
In furnaces the ratio of energy added to energy consumed is around 90%, which was pretty good until the emergence of heat pumps. There almost all the energy consumed is added to the output in addition to all the energy removed from the other side. That's why the efficiency in heat pumps is beyond 200%.
In summary, no. Cooling is not more efficient than heating. But given the temperature differential when cooling the energy consumption is usually higher.
> In A/Cs the ratio of energy (in the form of heat) removed to energy consumed is very low, around 10-15%.
Why is that?
Obviously I'm referring to efficiency in practice. In theory, heating and cooling should be equally efficient for a perfect heat pump, right?
> Air conditioning is a heat pump and can achieve up to 300% efficiency. Whereas most houses in cold climates use furnaces, which have at most 98% efficiency.
No. You can't directly compare "efficiency" numbers across different energy sources. My understanding is that the efficiency of gas powered electricity generation is around 33%, meaning that powering a heat pump with a COP of just under 3 will be of similar end-to-end efficiency as burning the gas directly in a condensing boiler/furnace.
End-to-end efficiency calculations are tricky and depend on a lot of variables.
Sure, but that doesn't mean you can throw your hands up and make an argument comparing nameplate efficiencies of things with different energy sources.
I'm well aware the figure in my above comment could be off by a decent amount due to transmission efficiency, what specific plants are generating marginal power, etc. But it's at least framing the comparison right.
Even in your worst case scenario, heat pumps are about as efficient end-to-end as a natural gas furnace. And renewable power is only going to become more common over time so it could get better.
To a consumer, comparing nameplate efficiencies as you say makes the most sense. I can easily find out how much a joule of electricity and a joule of natural gas cost me. Then multiply those with efficiency to see which is cheaper.
I did not put forth a worst case scenario. I put forth an example of doing proper comparison.
Based on a figure I just saw from someone else describing their setup (1.75 COP at 5 deg F), and taking into account transmission losses etc, the worst case would seem to be significantly less efficient than burning natural gas directly in a condensing furnace.
This isn't meant as some sort of knock against heat pumps! In fact I'm tentatively planning to add a heat pump to my own home within the next several years. Focusing on a worst case is still not an overall comparison of performance, but rather just one data point in the evaluation of a given design.
Multiplying the cost of the energy source by the nameplate efficiency is indeed another sensible way of comparing across technologies. But that isn't what you did in your original comment, where you juxtaposed two different types of efficiency numbers. That was my only point in my original comment.
Until the widespread use of heat pumps, AC was much more energy efficient than heating.
Can’t deal with a little extremes on earth?
Sort of makes one wonder how we’re ever going to colonize Mars so we’re not a single planet species.
As a thought experiment, the same logic can be applied to any region where lack of shelter or heating would make human life unsustainable.
If you completely ignore the concept of energy efficiency, sure.
That’s why I mentioned it as a thought experiment. We have been burning energy for centuries to keep folks alive in both extremes of climate.
Swamp coolers are massively underutilized as well. The vast majority of residential cooling in all but the most humid climates can be done with nothing but a fan and some cold water; no compressed gases necessary.
> The vast majority of residential cooling in all but the most humid climates can be done with nothing but a fan and some cold water
Aren't swamp coolers only really useful when the humidity is under something like 50%? I guess I'm assuming you're talking about the US, but I don't think "vast majority" of people live in such areas. A quick search for average humidity of US states in July and August shows many of them have an average daily humidity of over 50%.
It certainly rules out every place I've lived on the east coast (Richmond, Virginia, Long Island, and the Boston area), as the humidity in those places is usually at least 60% at the height of summer when most people actually use their AC.
As a side note, I suspect most people overuse their air conditioning and don't let their bodies adapt to the warmer summer weather. It's weird how many people keep their houses under 75 °F when the heat index is only in the mid 80s.
>Aren't swamp coolers only really useful when the humidity is under something like 50%?
They are less effective, but still work. As long as the dew point is ~72 degrees, or lower, they can still cool enough to do the job (although of course not to the extent of an AC). But yes, ultimately it comes down to people being ok with not setting the AC to 68 degrees when it's 80 degrees out, and using the minimal amount of cooling necessary to be comfortable.
This sort of true? There are many hours per year in many climates where direct evaporative cooling alone could suffice to keep people comfortable. However, most climates also have a good number of hours where air conditioning is required for comfort.
You can use this tool to visualize this: https://drajmarsh.bitbucket.io/psychro-chart2d.html
(Use the Givoni Bioclimatic Chart overlay and select a weather station using the globe icon.)
That said, there are a number of more complex devices which could further reduce how often AC systems need to be used: dew-point (Maisotsenko Cycle) coolers, indirect evaporation cooling, and thermal energy storage to name a few.
The issue with swamp coolers (evaporative cooling) is that you need relatively low humidity for them to work and they increase the humidity of the interior cooled environment. If you use them in combination with an air conditioner, they will very likely reduce the efficiency of the air conditioner by increasing the dehumidification load of the air conditioner.
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My 20 year old air conditioner recently died and I was looking into replacements. In my climate the temperature ranges from 40C in the summer, and -40C in the winter. After doing some research, it seemed pretty clear that having a furnace+AC was the way to go for my climate. Hardly a magic bullet technology.
Is that the typical range in a normal year? Or is that the all-time extreme record?
One thing people tend to do when they look at heat pumps is look at the typical extreme low for the year and size the heat pump based on that. But even if you touch -20 a few times a year, your heat pump doesn't need to be sized to heat in a constant -20. If you hit -20 once or twice per year then it's usually only for a few hours and the lowest that you really need to heat through is usually much closer to -10 or higher.
But, yes, if you're in a climate that sees frequent and sustained temps of -40 then a heat pump probably isn't for you or the rest of the Canadian Prairies.
Your best bet is also to spend a lot more on insulation. Combined insulation and efficient heating/cooling will keep your house comfortable. Overspending on one will not be as good.
You can also do heat pump for 90% of the time and emergency heat as oil/gas/wood stove.
Similar climate here, although days it gets below -10f / -23c are uncommon. Most winter days in a climate like this you could heat with a modern/high tech heat pump, but:
- It's probably going to be more expensive than heating with natural gas if you're in the northern US - at least as things are today.
- A modern/high tech heat pump capable of heating when the outdoor temp is < 10f / -12c is likely going to be quite a bit more expensive than a standard AC unit - making it even more difficult to justify financially
- A natural gas furnace can keep you warm (and keep your pipes from freezing/bursting) even if there's a power outage. It doesn't take much of a generator to run a furnace/blower fan.. but good luck staying warm with ONLY a heat pump in those circumstances.
The one thing that can really help improve the financials of getting a heat pump is if you intend to install solar power at some point in the future. Depending on your power company, you may be able to generate enough credit in summer with excess generation to pay for heat the entire winter. I'd still go with a heat pump AND gas furnace for backup though.
> I'd still go with a heat pump AND gas furnace for backup though.
Thankfully, this isn't too expensive of an option to do. Gas furnaces are cheap. Heat pump that isn't sized to go to -40F/C is also pretty affordable. The crazy high SEER ratings drive up the price.
-40C? That's an extreme situation. Heat pumps can be installed with backup heating as I understand it.
You also get "hybrid" heatpumps that work alongside other sources of heat.
> That's an extreme situation
Depends on where you live
Its 48C down to -10C here. Some years get down to -18, but not enough to build for it. That extra 8C has a qualitative difference to the steps that need to be taken for people and structures. The problem this year has been high humidity at that high end, much more than normal. When you have over 40% relative humidity and its over 45C it makes air conditioners work extra hard due the specific heat of the water vapor they are cooling. There were some dessication technologies being talked about last year that would really help as they operated prior to cooling the air but I haven't seen them rolled out yet. I've heard anecdotes about EVs refusing to operate due to battery safety, and public transit shutting down due to insufficient cooling capacity.
It's an extreme climate that ever reaches -40.
A vanishingly tiny percentage of the world population lives somewhere that regularly reaches -40°.
Fahrenheit or Celsius?
-40 is the one value where Fahrenheit and Celsius line up exactly.
Yes.
It doesn't matter.
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> Heat pumps can be installed with backup heating as I understand it.
Then, what's the point? If you still have to have gas lines and infra, just use the gas. It's vastly cheaper.
> Then, what's the point? If you still have to have gas lines and infra, just use the gas. It's vastly cheaper.
A) Not everywhere
B) Heat pumps can be powered with solar, reducing costs even if your gas would normally be cheaper
C) Some people are willing to spend a little more if it helps push electrification forward, for environmental reasons
> Some people are willing to spend a little more if it helps push electrification forward, for environmental reasons
It's not a little more though, that was the point. In my area, California, it's about 4x more. Gas here is so cheap, it's almost free.
Anecdotally, I don't know anyone who's opted into the "green energy" plans offered by the area's utility providers - because they all cost a lot more than regular.
People talk a lot - but their bank account dictates their actual decision making. Running a heatpump seems very expensive for a lot of the country, with negligible gains.
Natural Gas isn't exactly what we would call "dirty"... seems like a min-max issue, with people forgetting there's still areas burning coil and oil for electricity production.
> Heat pumps can be powered with solar
Not in the dead of winter you can't... not everyone lives in big cities folks, and where it snows, it gets quite cold.
Lots of places are looking into phasing out natural gas though. California gives you rebates for heat pump water heaters and there's plenty of discouragement to block new gas appliances and hookups.
There will be a feedback loop once that really starts: individual prices go up because infrastructure costs remain the same, but less people are using gas. Once natural gas prices go up, people will switch to more efficient appliances, or switch to electricity. Forcing prices to go up some more to make up for infrastructure costs.
I agree with you about people following their wallets and that's why people will want to change to heat pumps when gas becomes too expensive. Remember the prices in December?
I tend to need heat when the sun isn't warming everything up.
D) Carries the risk of killing you with CO.
That depends on the temperature difference. For smaller differences, heat pumps are much more efficient, but at some level they lose efficiency and gas is cheaper.
> Then, what's the point?
Minimizing your gas use?
I’m curious which areas this occurs on earth and what percent of population live there. I would guess a negligible portion. In the US, I would think it’s almost nonexistent. I’m from Minnesota and went to university in North Dakota - places with some of the coldest and most severe winters in the US. +40C in the summer and somewhat regularly down to -40C windchill temperature in the winter. If it were me, a place with actual air temperature of -40C with any kind of wind occurring would require multiple forms of heating for me to consider it safe for my family relying on only one or even two sources of heat doesn’t seem reasonable.
Most people live somewhere with vastly milder winters. Generalizing from your -40C winters is not useful.
Not generalizing, just saying if you live in a place with more extremes in the climate than a heat pump may not be ideal.
There is zero reason not to get a dual heat system. A heat pump vs pure cooling A/C is mostly just a reversing valve. There is almost no difference between the two which makes sense: A/Cs are just heat pumps setup to move heat outside the home. A "heat pump" heating system simply runs the other direction to move heat inside the home. Either way it is standard vapor compression with a compressor, two coils, and two coil fans.
Modern heat pump systems have an outdoor temp sensor and will avoid even trying the heat pump if it is too cold outside. Your installer should be able to adjust that setpoint. How low it can go depends on the refrigerant and rating... in the US higher SEER ratings often also means it can extract useful heat at lower outdoor temps.
tl;dr: The heat pump function is a trivial bit of material addition to a standard A/C and saves you gas/electricity even if it is only used for part of the cold season. There is no reason not to use one.
As a (small) reason, the controls involved in operating a heat pump plus furnace/fan are more complex than the controls involved in operating a plain air conditioner plus furnace/fan. (Possibly more than a little more complex if the heat pump is only operable under certain conditions and the heat pump and/or furnace is multi-stage or actually variable speed.). HVAC controls are very solidly stuck in the 1980s (or 1950s or whatever), with the main exception of highly integrated and proprietary variable speed heat pump controls.
I say this as someone who recently helped undo the damage after an inept HVAC technician replaced someone’s thermostat (for $500, thanks California prices) and did it wrong. The quality of the instruction manuals is low, and the quality of online resources about how conventional HVAC controls work is lower.
As far as I can tell, the theory is that HVAC systems used to consist of a bunch of discrete components, strung together, with control power coming from one or two transformers or thermocouples [0], and essentially no logic in the equipment. A relatively modern heat pump may well rely on a mechanism in the thermostat to protect the compressor. The actual equipment contains nothing resembling a microcontroller.
[0] Yes, the actual power available from the equipment to the thermostat may be negligible, and old thermostats were mercury switches on bimetallic strips that were powered solely by temperature changes in the room.
Same situation, but I'm looking to replace the AC with a HP. For a little extra money, you get the flexibility to choose your heat source. Newer thermostats can be programmed to switch between the power sources and you can hedge against one price fluctuations in one of the power sources.
Where do you live (general area) that you get -40 C often enough for it to matter?
Do you mean real -40? Or wind chill "-40" which doesnt affect HP?
Edit: Edmonton?
Heat pumps require more specialized techs to work on them too.
HVAC techs can work on Heat Pumps just as well as on dedicated ACs. They are not significantly different.
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