Air source heat pumps are super popular in Poland too, this winter it was about -20C for couple weeks straight and not had any problems, toasty house without an

Air source heat pumps are super popular in Poland too, this winter it was about -20C for couple weeks straight and not had any problems, toasty house without any issues. The key is that the heat pump exchanger really needs to be huge(ours is taller than a person) to get the heat out of the air.