Gas furnaces use the Annual Fuel Utilization Efficiency or AFUE. The higher the AFUE, the greater the efficiency and the greater your energy savings potential.
Because some of the heating potential of fuel is lost during furnace operation, no furnace is considered 100% energy efficient. THE AFUE percentage tells you the amount of fuel burned that actually goes toward heating your home on an annual basis.

Prior to the 1992 Federal Government regulations, most gas furnaces were manufactured with standard efficiencies ranging from 60 – 78% AFUE. If you have one of these older units and replace it with a new Comfortmaker 90%+ AFUE, you can save as much as 40% on your utility bills!

• DOE Minimum : 78% AFUE
• Energy Star Minimum: 90% AFUE