What is AFUE?AFUE stands for Annual Fuel Utilization Efficiency, which is a means of measuring the efficiency of a furnace or heater.
It is measured in percentages (i.e. 80% AFUE, 96% AFUE), where the percentage represents the amount of fuel directly translated into heating your home. For instance, an 80% AFUE furnace would transfer 80% of the fuel burned into heating your home, and the additional 20% would be lost as thermal-waste through the exhaust stack on your roof.
For more on AFUE, try:
What is AFUE and How is it Used?