[ChrisIsTaken]

Energy loss through an insulator is exactly linear to temperature.

The problem is that people who would have otherwise tolerated 50F temperatures without heating by putting on a sweater are pulling their old oil column heater out of the storage.

[makomk]

One other problem is that one of the ways people have been making their heating more efficient is by using heat pumps, and their efficiency gain drops off with lower temperatures until they become no more efficient than the resistive heaters they replaced during the kind of unusually cold weather Texas is apparently seeing. This makes the peak to average power usage problem even worse.

[ece]

More modern heat pumps can be efficient at up to around -10 degF[1]. Higher efficiency federal/local rebates are not bad across the US, so I wouldn't be surprised if these were installed in some TX homes. It's still a capacity problem if average use is 10hr/day instead of 2hr/day and your house has no gas furnace heating. I would guess most TX (Dallas/Austin) homes probably do have a gas furnace, but maybe not in coastal/south TX (Houston).

[1] https://daikincomfort.com/go/aurora/

[PeterisP]

Are their heat pumps linked to outside if their efficiency is so affected? The models I see generally pipe underground, where the temperature is mostly stable and isn't affected by a week of unusually cold weather.

[sokoloff]

The overwhelming majority of heat pumps across the US are air-source (rather than ground-source), so "yes, overwhelmingly".

[adrianN]

Oh you're right.