This is just plain false. The entire country of Finland (and Sweden, and Norway) installs pretty much only air source heat pumps, air-water heat pumps, or groun

This is just plain false. The entire country of Finland (and Sweden, and Norway) installs pretty much only air source heat pumps, air-water heat pumps, or ground source heat pumps in all renovations or new built buildings. In the north of the country you end up heating your house for some days with resistive heating, but it is still cheaper than any alternative source.