We heat our '''“all-electric”''' eastern Washington home with multiple oil filled radiators in the winter months because it is more efficient than our Trane Variable Speed R-410A heat-pump system, which we leave programmed to assist during cold spikes. During the winter, heat pumps operate like an air conditioner in reverse. The refrigerant absorbs heat from the air outside and uses it to warm your home. But the heat pump system has mechanical parts and uses a squirrel cage fan to force air through the ducting whereas the oil filled radiator converts electricity directly into heat and uses convection. Note: We have low-cost renewable hydro-power nearby.