That's fine, however, if you're using heat at all in your home, having a "mining laptop" and a few incandescent lights around to take the chill off is not going

That's fine, however, if you're using heat at all in your home, having a "mining laptop" and a few incandescent lights around to take the chill off is not going to increase your electricity bill, unless you're using gas for heat. I forget the ranking of efficiency, heat pumps are more efficient than resistive heating (to a point well below -15 for more expensive units); however i forget where gas fits in that spectrum. having a couple hundred watts of heat per person will lower your overall heating bill, all else being equal.