A: Electric back-up heating is feasible, and many contractors push it as the source of back-up heat when heating with heat pumps. But they are not paying the bills. Using utility electricity at 23c/kWh of electricity to run an electric resistance heater means heat would cost me 23c/kWh of heat in the house (electric-resistance heating elements are 100% efficient at converting electricity to heat) but my oil furnace costs about 8c/kWh of heat in the house. Natural gas costs about half this.