It's not that retro. In some places in the world it's still very common, and heat pumps very uncommon. It's a response that makes sense in the right climate (an

It's not that retro. In some places in the world it's still very common, and heat pumps very uncommon. It's a response that makes sense in the right climate (and I should note Carter did create a tax credit program for it, though it never got popular in the US).