In New Hampshire we ecowarriors like to tut-tut about those wasteful southerners with their air conditioning, but the hard fact is that heating a home comfortably up here usually takes more energy than cooling it comfortably down there.

That makes sense from sheer physics: There’s a 50-degree difference to overcome in a typical winter day (20 degrees outside, to 70 degrees indoors) but rarely more than 30 degrees to overcome in the southern summer (100 degrees outside to 70 indoors). It’s not quite that simple due to efficiencies of different technologies, but you get the idea.

A recent analysis puts it this way: “Residential air-conditioning loads contributed less than 1 ton of carbon-dioxide emissions per household on average over the course of a year. But the same homes in northern climate regions can emit anywhere from 3 tons to as much as 15 tons of CO2 from heating.”

That’s why weatherizing buildings is a great way – as in effective and cheap – to lower the chance of a Texas-type grid meltdown due to cold weather, as this story from Canary Media makes clear.