[nfriedly]

> That would just be... electric heating, but with more steps? I mean, at that point you just have a heat pump _and_ electric heating; a hybrid system. It's better, sure, but it's not really just a heat pump anymore.

I have a geothermal system (a ground-sourced heat pump) that also has electric resistive heating as a backup. I I've had to use it twice in the ~5 years I've lived in this house. The first time it was something like -15°f outside, so we just figured that was beyond what the system could handle. The second time, a year later, it wasn't quite as cold out and we had someone come look at it who found that it was low on refrigerant. (I've only been here 5 years, but the system was at least 15 years old.)

So, I've been happy it to have it there as a backup. From what I understand, it's also fairly straightforward and inexpensive to add to the system.