> I thought all electric heaters were essentially 100% efficient, due to conservation of energy.
Well, gas heaters are a lot more than 100% efficient in terms of heating per unit of electricity consumed, so better for the grid.
(Before anyone else points it out, yes, electric heat pumps are usually more than 100% efficient, too, but that's not relevant here because in severe cold, they are less efficient than direct heating.)
Cold-weather residential heat pumps have gotten a lot better in the last 10 years or so.
Mitsubishi's residential air-source ductless mini-split heat pumps that have their "Hyper-heating inverter" technology are greater than 100% down to at least -13℉ (-25℃), although their capacity starts dropping fairly linearly from 100% at 23℉ (-5℃) to 76% at -13℉ (-25℃), so unless you oversized your system a bit you might have to put up with your house being a few degrees cooler when it gets very cold outside for a long time.
Their efficiency remains above 180% down to around -5℉ (-20℃).
In most of the major cities of Texas these would have worked fine and remained around 200% or higher efficiency and around 90% capacity. Only a small number of people would have had them get down to 100% efficiency.
Fujitsu and Daikon have similarly performing heat pumps.
That's interesting to know. I had this heat pump in Florida that couldn't keep up with an external temperature of 49 F. That kind of made decide they were useless. Maybe if at some point in the future I have to buy a unit I will reconsider it.
Recently the guy from Technology Connections on YouTube made a very good point:
Consider technology and tools as they are now, not as you last disliked them.
Air source heat pumps aren't efficient in extremely cold outside air, and so you're back to resistive heating - but for ground source you should see very little change, because the temperature of the rock under you doesn't change suddenly on a cold day. If we have a century of cold weather the rock will cool down, but one particularly icy week won't do it. The ground effectively is your heat battery, pump heat into it in summer (removing it from your home), pump heat back out in winter (to heat your home up).
Well, gas heaters are a lot more than 100% efficient in terms of heating per unit of electricity consumed, so better for the grid.
(Before anyone else points it out, yes, electric heat pumps are usually more than 100% efficient, too, but that's not relevant here because in severe cold, they are less efficient than direct heating.)