we switched to a heat pump last year and we’ve been mostly pleased. that said in the last cold snap when wind chill temps fell to -30 (we live in chicago) the entire system shut down! we talked to the installers and they said that when articles like this way “works down to -10” you have to understand that it’s the wind chill temp. also i’m sure there are other pumps on the market that would have faired better. we have a mitsubishi mini split.