Your electricity likely comes from burning coal. Coal pollutes quite badly.
Other ways to heat a dwelling are more efficient. For example natural gas heaters burn cleaner and energy losses are much smaller compared to all the conversion losses (by the time you produce a BTU of heat from electricity, several BTUs of energy have been lost due to conversion losses, while burning gas is much closer to perfect efficiency though obviously not perfectly efficient). Or if you can use co-generation, you essentially produce no noticeable environmental impact at all. Or you could go the other route and invest in insulation or a molten salt wall for passive heating.
But electricity isn't inherently dirty, right? It's probably better to have the network shift to greener sources than have every consumer do that individually.
Right. If you use solar panels you are definitely better off. The question is whether you are or not and for the time being most places still don’t use renewable energy sources.
Other ways to heat a dwelling are more efficient. For example natural gas heaters burn cleaner and energy losses are much smaller compared to all the conversion losses (by the time you produce a BTU of heat from electricity, several BTUs of energy have been lost due to conversion losses, while burning gas is much closer to perfect efficiency though obviously not perfectly efficient). Or if you can use co-generation, you essentially produce no noticeable environmental impact at all. Or you could go the other route and invest in insulation or a molten salt wall for passive heating.