In nordic countries heat pumps (and good insulation) are more common for heating than gas. To echo the sibling comment, cold weather air heat pumps work, they

In nordic countries heat pumps (and good insulation) are more common for heating than gas. To echo the sibling comment, cold weather air heat pumps work, they get efficiency over resistive heating down to about -25 or -30C, and are widely used in colder climates. There are also ground and water heat pumps that exploit the higher ground/water temperature in the winter. There are also utility scale versions of these used in district heating plants.