WHAT DOES AFUE STAND FOR?
Annual Fuel Utilization Efficiency
HOW IS AFUE MEASURED?
AFUE measures a gas furnace's efficiency in converting fuel to energy. A furnace that has an 80 percent AFUE rating can turn 80 percent of the energy it consumes into heat. The other 20 percent is used during the heating process.
WHAT IS A GOOD AFUE?
A higher AFUE rating means greater energy efficiency. The minimum standard AFUE for new furnaces is 78 percent. A mid-efficiency furnace usually has an AFUE rating between 80 and 85 percent, while a high-efficiency unit has a rating between 90 and 97 percent.