I live in an apartment in Norway where an air heat pump is not allowed by regulations and the ground source is way too expensive even with the current electricity prices and will take years to get approval as the area is considered a historic part of the town and must be preserved.

So couple of years ago I permitted for my son to mine coins on GPU when it was cold allowing to him to earn like 2-4 Euros per day.

But then I stopped as I realized that this just promoted insanity of using proof of work in other places.