There have been a number of startups selling crypto-mining electric heaters, but they've all faced the same problems:

- They're much more expensive than normal heaters, and the returns on mining don't make it cost effective.

- If you've spent that much money on heaters/miners, you're going to want to max them out 24/7 before they become obsolete rather than just switch them on when its cold, which defeats the point.

- They'll also need to be upgraded every 6-12 months to keep up with the mining arms race, and no-one wants to have to replace their super-expensive heating system that often.