Energy Savings

AFUE (gas heating)

The efficiency of a furnace is measured in a rating known as AFUE (Annual Fuel Utilization Efficiency). A lot like your car’s miles per gallon rating, AFUE tells you how efficiently the furnace converts fuel (gas or oil) into heat. An AFUE of 80% means that 80% of the fuel is used to heat your home, while the other 20% basically goes up the chimney.

The government has mandated a minimum 78% AFUE rating for furnaces installed in new homes. (In contrast, many furnaces manufactured before 1992 had AFUE ratings as low as 60% — so nearly half the fuel was being wasted.) If you have an older furnace (with an AFUE of about 60%), you could save up to 40% on your heating bills by replacing it with a new high-efficiency furnace.