This is a really interesting point that I don't think gets enough attention, so I'll call it out: in general, it takes less energy to air condition than to heat

This is a really interesting point that I don't think gets enough attention, so I'll call it out: in general, it takes less energy to air condition than to heat because the differentials are greater -- meaning: it's easier to air condition from 45 to 25c than it is to heat from -5 to 25c, simply because 45 - 25 < 25 - -5.