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Lots of happy customers in this reddit thread: https://www.reddit.com/r/heatpumps/comments/146jg7k/cold_cli...
Some customers will accept that. Most will not. Reddit is not a particularly representative sample of the entire market.
The tech has limits and cold weather states can't avoid that or the reputation will get really bad and the tech will fail.
Jan 18, 2016 -21°F Coldest day of that winter
Dec 19, 2016 -21°F Early-season Arctic outbreak
Dec 27, 2017 -19°F Part of a prolonged late-December cold wave
Jan 2, 2018 -23°F Deep freeze to start the year
Jan 30, 2019 -30°F Coldest Chicago temp since 1985; “Polar Vortex” event
Feb 14, 2020 -18°F Valentine’s Day Arctic blast
Feb 7, 2021 -21°F Mid-winter cold snap
Dec 23, 2022 -23°F Pre-Christmas Arctic front
Feb 3, 2023 -17°F Last occurrence to date
edit: downvoted for noticing that it is cold.
The regular AC and gas furnace combo works and is cheaper so I stuck with that.
Its true retrofits are a tough sell and natural gas is really cheap here. It would help if the US took insulation more seriously. But for someone with oil or electric resistance its definitely a big win.
If you can afford it, and have the land access, you could install a ground-source pump which should benefit from more stable temperatures. As with all heating/cooling, these systems work best if your house is well insulated. That's a much bigger problem in the UK, and I imagine the US too, especially in places where solar gain requires a huge amount of A/C usage.
[1] https://www.cell.com/joule/fulltext/S2542-4351(23)00351-3
Though good heat pumps are hard to find in the northern US. Most installers only know of gas furnace + A/C, and don't even try to install anything else. As you get farther south in the US heat pumps become common, but there it rarely gets much below freezing and so they don't need backup heating systems at all.
Cold climate heat pumps work just fine at even -30 C. In fact, many malls and offices in Northern Ontario are switching to heat pumps only because electricity is so cheap. What heat pumps really need in cold climates is reasonable insulation.
t. certified
Like any piece of equipment, just check the specs before you buy...
A normal person is scared of the prospect of losing heating when it's most needed. -15F accounts for many places in the US, but many others, not so much. Even New Jersey, which we don't think of as the frigid North, can theoretically drop below that number, and nobody wants "almost always" when it comes to life-giving heat in the coldest winter.
People being "scared" is how north america ended up with vehicles the size of tanks. The vast majority of cold climate heat pumps work down to - 20 C in most cases and down to -30 with better models.
If you live in Minnesota stick with gas, we'll be ok. The majority of the population will never hit -15F.
For the west coast or areas south of 40 degrees north and east of the Rockies in the US and most of Canada where people actually live (southern Ontario is warm to due Lake Ontario), heat pumps are probably more efficient and cheaper overall.
Minnesota is definitely an outlier with regards to heat pump vs natural gas heating.
Institutional type buildings in Minnesota are switching over to condensing boilers, which are amazingly efficient, well over 90% of the heat is used, and they’re a fraction of the size of the old tube style iron boilers. I’m personally involved in multiple commercial boiler replacements a year.
I am seeing more geothermal installations in MN as well, that works better than air source heat pumps in Minnesota due to the source/sink being a stable 50F instead of having a 80-90F delta like an air source heat pump when it’s -20F outside
One more thing, both Minneapolis and St Paul have district heating and cooling systems in their downtown areas. The University of Minnesota also operates district chilled water and hot water plants in both their Mpls and St Paul campuses.
This is actually why older heat pumps became less effective around 40F because the coils would start to hit 32F since they are attempting to pull heat from the warmer outside air and are therefore colder than the outside air.
There are various solutions to this problem, the standard way is to run it in reverse as a air conditioner for a short period if it detects the situation to defrost the coils and if the system has resistive heat strips it uses those to warm the air that is being cooled. This obviously reduces the efficiency of the system the more it has to defrost and may not be very comfortable to the users.
Cold weather heat pumps work better in drier climates due to this as well because the lower the outside humidity the slower frost will form on the outside coils.
Some cool weather heat pumps will have two compressor units and fans and alternate between them with one defrosting the other, there are many other tricks they are using to prevent frost buildup and continue working above COP 1 far below freezing.