They’ve been used in warmer parts of the country for quite a while, but ones which remained highly efficient below freezing only became commercially available in the US a few years ago.
Depends. There are ones like that still sold. There are ones which don’t switch to resistive heat until -10°F. Probably even colder too, but not sold where I live
They’ve been used in warmer parts of the country for quite a while, but ones which remained highly efficient below freezing only became commercially available in the US a few years ago.
Any idea what operating range the US ones have? Are they still r32?
Depends. There are ones like that still sold. There are ones which don’t switch to resistive heat until -10°F. Probably even colder too, but not sold where I live