“As long as your house is properly air-sealed and insulated, an air-source heat pump can perform well beyond temperatures of -13 degrees Fahrenheit! Some newer models can handle temps as low as -22 degrees. If you live in extreme cold, you may need to use supplemental heat, or what’s called a dual-fuel system (or consider switching to a ground-source heat pump).”
https://sealed.com/resources/winter-heat-pump/
In theory on paper. In practice, not so much.
It not whether they can operate when it’s cold, but more whether they can operate EFFICIENTLY when could, plus, of course, the purchase price for these types of heat pumps. From what I can see, when very cold they’re better than resistance heating, but not by much, when temperatures are mild, they do much better. Even the government goal of 1.5 to 2.0 in COP means that the government knew there were limits, since ANY heat pump, even the cheapest, easily gets 3.0 or higher during their designed-for temperatures, roughly 45-50F.
“an air-source heat pump can perform well beyond temperatures of -13 degrees Fahrenheit! S”
The low pressure side has a temperature of -50F I think. So that is the limit below which it does nothing. Probably at 0F it has lost half its ability to warm the cold side from the ambient air. I think the efficiency improvements are related to increasing the pressure on the high pressure side, which reduces the temperature of the low pressure side when the refrigerant is allowed to expand. They are expensive and any cost savings is gone when natural gas is an alternative at current price, delivered, of about $1.20 per 100 cubic feet. 100 cubic feet of natural gas has the BTU of about .8 gallons of heating oil. But when the government makes fossil fuels illegal it will be great to have a heat pump.
Burn wood. Stuff heat pumps and EV’s. Only 6 years left anyway.