In the short term, purchasing an electric furnace is cheaper than purchasing a gas furnace. In the long term, gas furnaces are cheaper to operate than electric, according to Bryant Air.
Electric furnaces generally last longer than gas, meaning they do not require replacement as soon as a gas furnace. Most electric furnaces last 20 to 30 years, according to Bryant Air. Gas systems generally last about half this amount of time. Nonetheless, gas costs are lower than electricity costs for comparable units. The bottom line is that electric furnaces are cheaper to install and last longer, while gas furnaces are cheaper to run, but generally do not last as long.