Is an Electric Space Heater More Efficient Than Your Gas Furnace?

The short answer is probably not. All of these devices turn electricity into heat, gas indoor heater which can be done at an efficiency of 100%. (This is true when we consider site energy only, not all the losses that occur between the power plant and your home. If we include those, the efficiency is closer to 30%.) If you have a natural gas furnace, portable gas room heater its efficiency is probably in the 80% to 95% range