It could be interesting to burry heating coils in the ground under the house and maybe dig deep, insulated petimeter foundation to better keep the heat inside.

It could be interesting to burry heating coils in the ground under the house and maybe dig deep, insulated petimeter foundation to better keep the heat inside. Power them with solar of course at times of negative prices. Or dig out a deep cellar, insulate on the sides and a the bottom against heat loss and moisture and put back the earth you dug out with heating element in the center. You don't even have to insulate wires that go through earth to the heating element because electricity passing through earth will get turned to heat as well. It might be nice additional heating for cooler climates. If you dug deep enough to have actual cellar on top of that you'd have a very warm cellar, you could put underground swiming pool there.