Comment by avianlyric

Add insulation, and use a heatpump. The more insulation you add the easier it easy to keep a space warm. Add enough insulation, and eventually the waste heat production from human activities inside the space will equal or surpass the heat loss through the insulation, removing the need for additional heating.

Insulation obviously also helps keep a place cool. But no amount of insulation will ever remove the need for cooling if the outside is warmer than the inside. Energy is always going to move from a hot place to a cold place, but at least insulation lets us control how quickly that happens.

Also the limit on air sourced heat pumps in cold conditions is basically caused by water freezing on the evaporator coils, effectively adding a layer of insulation that limits how much energy can be drawn from the air, we’re not really limited by the refrigerants. As other have mentioned you dig down to find a better source of heat, and often you don’t even need to dig far, a 20-30cm trench is often enough. Although in super cold climates you’ll need to go deeper to make sure your through the frost layer in the winter.