> Further heat pumps are good to 25 to 30 degrees Fahrenheit, under that a gas furnace is normally used to supplement a heat pump in colder climates. Most heat

> Further heat pumps are good to 25 to 30 degrees Fahrenheit, under that a gas furnace is normally used to supplement a heat pump in colder climates. Most heat pump manufacturers do not recommend operating a heat pump in below freezing conditions Just wanted to chime in that they do make a lot of low-temp heat pumps, going down to -30f now. The efficiency drops dramatically at temps that low, the best site to look at cold-weather models is https://ashp.neep.org/#!/product_list/ https://ashp.neep.org/#!/product_list/ If you look though, the "COP @ 5 degrees F" for a lot of models is above 2.0, which from my understanding means you'll be using 1/2 the electricity someone with baseboard (resistance) heat would. And above those temps the COP gets much higher.