My homelab is in a closet that has the water meter for my above-garage apartment. Before I put a heater in the garage itself, I needed to make sure that that closet didn't freeze. I rigged up a temperature sensor to start mprime on a server if the temperature got too low, but higher than the electric heater that's also in that closet. I figured I might as well contribute to research if I'm just burning watts for heat anyways.
I remember some startups trying to install cryptominers in people homes, the idea was to use the electricity that would be spent heating the space anyways. The company would pay for the mining hardware while the customer would provide the electricity, and the profits would be shared.
I don't know how it worked out, but the idea was there.
I know of this one [1], a 1000W space heater with integrated cryptominer. Looks kike you can actually buy it now. Not sure how much the mined crypto offsets the heating costs though.
My understanding is that for most residential heat pumps, the temperature needed to make the heat pump less efficient than resistive heating is so low that it enters a range that the pump doesn't even work anymore.
However, that's only a measure of efficiency. It could still be that the throughput isn't enough. A 30 kW resistive heater can ALWAYS output 30 kW of heat. But my 7 kW heat pump could produce anywhere from 14 to 30 kW depending on outside temperature.
Does that mean the heat pump gets less efficient as the outside warms? Because that would be fine. 7kW to make you home a constant temperature seems wonderful.
