what a perfectly reasonable approach
Surely there are some combined solutions where the house boiler can heat up from electricity (like a boiler) and gas. Its clear that its cheaper to warm up with gas, but if electricity, in addition to heating, carries out some other useful activity (even not necessarily mining), then it may come out cheaper, and maybe it will also bring profit
but if electricity besides heating will carry out some more useful activity (not even necessarily mining), it may come out cheaper, or maybe itll bring profit