If you don't use heat pump (which can have 300-500% efficiency), whatever you plug into a wall socket will produce heat at exactly 100%. So the real choice here is either monetize what you are doing with electricity or using a heat pump

my friends have been heating their apartments in the winter mining cryptocurrencies. they're not into crypto, in that they don't do it in the summer, it just helps offset the cost in rentals without heat pumps -- gamers who've already purchased the gpus