Furnace System GuideElectric furnaces heat air by passing current through resistance heating elements, with no combustion and no flue. That makes them simple and clean at the point of use, but the running cost is where they differ most from gas. This page explains how electric furnaces heat and why site efficiency and operating cost are two separate questions.
How an Electric Furnace Makes Heat
An electric furnace uses electric resistance heating elements instead of a gas burner. Current flows through the elements, they get hot, and a blower moves air across them and into the ducts. There is no combustion, so there is no flue, no gas line, and no exhaust venting to manage.
Because all of the electricity consumed is converted directly into heat, electric resistance heating is often described as 100 percent efficient at the point of use. There is no exhaust carrying away part of the energy the way a gas furnace's flue does, which is why electric furnaces do not carry an AFUE flue-loss penalty.
That point-of-use efficiency is only half the story, though. It measures what happens inside the house, not how much energy or money it took to deliver that electricity or to run the system over a season.
Why 100 Percent Efficient Does Not Mean Cheap
Site efficiency and operating cost are different measures. An electric furnace can be 100 percent efficient at the point of use and still cost more to run than a gas furnace, because the price per unit of delivered heat depends on fuel price, not just efficiency.
Electric resistance heating is also far less efficient than a heat pump, which moves heat rather than making it. The Department of Energy states that most homes heating with electricity today use older, less-efficient electric resistance technology, which requires at least twice as much energy as a heat pump to keep a house warm. That is a large gap in energy use for the same comfort.
So the operating-cost comparison usually runs against a home electric furnace in two ways at once. Electricity often costs more per unit of heat than natural gas, and a heat pump can deliver the same heat using a fraction of the electricity an electric furnace needs.
Where Electric Furnaces Fit
Electric furnaces make the most sense where there is no gas service, where heating loads are small, or where the upfront simplicity and low install cost outweigh the running cost. With no combustion, they avoid the venting and combustion-safety requirements of gas equipment.
Heating is not a minor part of a home's energy use, which is what makes the operating-cost question matter. The U.S. Energy Information Administration reports that space heating and air conditioning together made up 52 percent of a household's annual energy consumption in 2020, so the efficiency of the heating system has a large effect on the total bill.
Regional climate shapes the decision as well. The EIA notes that households in the Northeast and Midwest consume more energy on average than those in the South and West because of higher space-heating demand, so an electric furnace's higher running cost bites harder in cold-winter regions with long heating seasons.