Comment by triceratops

> You can always use a heatpump to heat a space.

I covered that in the rest of my post. Most of the time, heating involves a much bigger temperature gradient than cooling. And even though you can use a heat pump, most houses don't use one. (I love the tech personally). Meanwhile cooling always uses a heat pump, so almost every air-conditioned house is using more efficient tech than a heated house. While operating on a smaller temperature delta.

> There is no passive manner that can allow you to cool a space surrounded by a hotter space

Insulation works just as well to keep heat out as it does to keep heat in.