Nothing really new here. Folks have been using them so replace/supplement cold weather heating needs for years. I have 5kw of miners running at home keeping the basement at 85F even in winter. The heat comes through floor taking care of the rest of the house. Only when it gets to below 10F outside do I need the furnace to run so in winter now the miners not only earn enough to more than pay for their feeding but in fact earn even more because rarely does the furnace run. As reference, pre-mining days it typically cost me around $400/mo for the heating bill.