The heaters them themselves are cheap, but running them is not. I've done the calculation for my situation last year in Germany, and using the gas heating came

The heaters them themselves are cheap, but running them is not. I've done the calculation for my situation last year in Germany, and using the gas heating came out much cheaper (at least with gas prices last year). I think that's because most portable electric room heaters are not as efficient as the built in gas-based heaters. Does anyone know more about this topic?