Comment by avianlyric

There’s a reason I say living space, I.e. a space with people living in it.

A living space will naturally heat itself with zero furnaces or electric heaters. Because the living things inside it will always produce heat (at least until they cease to be living). On the other hand, you’ll have a hard time getting living things to cool any space they occupy.

> On the other hand my air conditioner moves 3.5W of heat outside for every 1W of energy input.

Heat pumps work both ways, and it’s still easier to heat a space with a heat pump than cool it. Sure your AC can move 3.5W of heat for 1W of energy input. But that means 1W of energy allows you to remove 3.5W of heat from a space. But if you used the heat pump to heat the space, you would get 4.5W of additional heat, because that 1W of energy used to power the heat pump becomes waste heat that can be trivially captured and used to heat the space.