What Does AFUE Stand For?

AFUE is the acronym for Annual Fuel Utilization Efficiency. This number calculates a heater’s output versus the ratio of its total energy consumption. The higher the percentage of AFUE, the greater the efficiency. Every U.S. furnace is at least 78 percent AFUE because of government regulations. A boiler or furnace with 90 percent AFUE means that 90 percent transforms into heat energy while the other 10 percent of the fuel travels via vents and the chimney, never turning into energy.

Hoffmann Brothers, heating and air conditioning contractor, says: “Never purchase any heating system that does not illustrate its AFUE. The Federal Trade Commission (FTC) mandates that any new boiler, heat pump or furnace feature an AFUE, enabling homeowners to assess models based on heating efficiency.”

Pay Attention to These AFUE Factors When Making a Purchase

  • When shopping for a furnace or boiler, always check the minimum AFUE requirements
  • The Department of Energy and the Environmental Protection Agency regulates minimum AFUE standards for all types of heating systems. For instance, a gas-fueled steam boiler is required to have a 75 percent AFUE and a fossil fueled boiler must have a minimum of 80 percent AFUE.
  • As for heating systems, without flue loss an all electric boiler and furnace generates an AFUE rating ranging from 95% to 100%.
  • Older heating systems have a very low AFUE ratio, between 68 to 72 percent.
  • However, AFUE is not the only determinant, which represents a heating system’s efficiency. Sealed combustion, flue pipe diameter, as well as an electronic igniter are three other features, which influence a heating system’s efficiency.

The Real Value of AFUE Rating

AFUE directly correlates to how much money you spend when heating your home in the winter. When you have a furnace with 90% AFUE, you spend $1 on natural gas but only 90 cents of that dollar heat your home (the rest escapes as exhaust). The higher the AFUE, the less fuel used and the less money you spend on heating. If you’re considering installing a new furnace, factor in AFUE. If you buy a high AFUE furnace, you will save more money over the lifetime of the HVAC unit.

Contact the St. Louis HVAC contractors at Hoffmann Brothers to get all of your important AFUE questions answered.