Very Good Gas Furnaces 80% AFUE Single Stage What does having an 80% Furnace mean? Furnaces are measured using AFUE (Annual Fuel Utilization Efficiency). The higher the AFUE rating the more energy efficient your system is and the lower your energy costs will be. For example. The Frigidaire 80% line of furnaces will deliver a minimum of 80% efficient heat. Compare this to an older furnace that may only deliver 60% efficiency. The Frigidaire 80% technology is all about saving you money for years to come.  | *Dollar amounts computed at $.092 ccf, for 2,500 full-load heating hours and a system rated at 60,000 BTUh. Actual savings vary depending on climate conditions, fuel rates, and patterns of usage according to individual lifestyle. | |