Maybe totally fine for you. But that will not be "totally fine" for much of the US when they are expecting to keep their house at 72 degrees and the new technology they got talked into can't do it.
The tech has limits and cold weather states can't avoid that or the reputation will get really bad and the tech will fail.
I'm not sure if you've lived in prolonged -15F areas, but many conventional heating systems struggle too... especially in poorly insulated houses. People often have wood stoves or other ways to compensate.
and if you believe that heat pumps do not work below freezing temperatures, you are part of the reason why misinformation keeps spreading. You should know better. You should be ashamed to be spreading straight up lies.
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
What's relevant is not how cold it got on the coldest day of the year, but how warm it got on the coldest day, and how long it stayed cold. If the daytime high is mild enough that an undersized heat pump can keep the house at 72, it will take time for that house to cool from 72 to eg. 63 when the temperature drops overnight. And since the heat pump is still trying to keep the house warm, it'll take a lot longer for the house to cool off than if the heat were turned off entirely.
It makes sense but I just wasn’t willing to trust that with my checkbook, you know? There’s how it’s supposed to work on paper and then a reality where I’m stuck with it.
The regular AC and gas furnace combo works and is cheaper so I stuck with that.
Even at 0F most modern heat pumps produce heat at a COP greater than 2. This means you get twice the rate of heat generation than a typical electric space heater. You are out of date, and wrong.
You see this opinion a lot in the US, probably a result of Fox and its ilk. As the article mentions, somehow Nordic countries and Canada manage to use them. There's been good uptake in places like Maine which is good news.
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.
Below freezing is a concern that everyone has in Northern Europe, particularly Scandinavia which has very high per-capita adoption. The units might be harder to find in the US, but they definitely exist.
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.
Northern Europe tends to have a mild climate in the places where people live. The Northern US is significantly south, yet gets significantly colder winters. There are places in Europe that get worse than the Northern US - but they are places where few people live and so not normally what you are talking about when talking about Europe.
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.
that's odd because Ontario and Quebec are colder than most of the US and just these two provinces account for about one million heat pump installs per year since 2020.
Heat pumps can work great in the northern us. However the experience of europe mostly doesn't apply. You need backup heat of some sort to use a heat pump.
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.
That is true only for air heat source. And even those work in below freezing (the one I have works down to -20degC) but as you say... with diminishing returns. Still, checking the technical spec, it says that at -15 degC it heats up a tad under 3x as much energy it uses. Pretty good I would say!
Yep, you get what you pay for. They've started fielding systems that will handle extremes much better, but you dont get that kind of performance without tradeoffs. cascade systems, 200psi r600, 450psi CO2, refrigeration systems are an engineering game irl. They require much more experience to design, setup, and charge correctly. The biggest issue I have with heat pumps for life support heating/cooling, is they have so many single points of failure its scary. Compressors can and will die if anything else in the system goes too far out of the intended cycle. Extreme weather moments or natural disasters can physically break condensors, evaporators, and lines. Electrical surges can and will fry computers, inverters, and controllers. And almost none of those can be serviced on your own.
The backup system can be resistive heaters which are inexpensive and low maintenance, and their lower efficiency isn't that big a deal when you're only using them 2% of the time.
This is outdatated nonsense, I had my system installed 10 years ago and it works down to -15F... even the cheap $1k systems on Amazon work below freezing now
Like any piece of equipment, just check the specs before you buy...
It's semi-true even with modern systems and shouldn't be outright dismissed as "nonsense".
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.
no, this is complete nonsense and should be dismissed as such.
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.
What’s the COP at -15F? It’s probably close to 1, which means you’re paying for resistive heat which happens to be the most expensive possible way to heat something up.
That’s the thing, I do live in Minnesota. Most of the lower 48 can benefit from heat pumps but unfortunately in Minnesota (and the upper Midwest that isn’t directly adjacent to a Great Lake which moderates the temperature) you either need resistive heating on the heat pump condenser coil to prevent icing and/or a backup natural gas furnace/boiler for the few weeks it stays below zero for days on end.
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.
Whoops, my bad when doing the transformation. It won't work that low, only down to 20degC and at that point it probably approaches 1. Lucky me, the temps never dropped to under 19degC in the last 20 years in my area. So I'm probably going to be fine.
Not exactly true, one of the main issues with heat pumps in cold weather is the outside coil freezing up with ice blocking airflow due to them being below the freezing point of water.
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.
