I have heard from a trusted source that people in Russia are buying graphics cards by the truckload and building mining farms, and getting free electricity by bribing utilities / government officials. So keep in mind that you are likely competing with Chinese and Russian miners who don't have the same costs.
Its not cold in the summer, and it probably too cold in winter to not have any interior climate control. With much lower cost of living and cheap electricity, China seems like a much better option, the majority of mining is actually done there.
Mais, in the winter, the waste heat is free heat. Basically, if you deduct the money that you would have spent on heat, the electricity is very cheap.
Another way to think of it: The heat from a bitcoin rig is the same that you would get if you used an electric space heater or an electric baseboard heater. These cost about 2-3x as much to run as a gas or oil furnace. So, if you're able to turn off your heat and just heat with a bitcoin rig, your "cost" is less because you're not spending money on something else.