The P. Gagnon & Son Blog

What Is the Efficiency Rating for Furnaces and Boilers?

Learn more about AFUE

afue rating maineWith the cost of everything so high lately, your purchase of a new furnace or boiler for your Seacoast Region home takes on added importance.

This is a major investment in your home’s comfort and value. Fortunately, you have the heating system experts at P. Gagnon & Son ready to help! We sell, install, and service both oil-fired and gas-fired heating systems.

Once we install your new heating system, P. Gagnon & Son’s trained, experienced service technicians will help keep it running at peak efficiency with annual tune-ups, which are included in our affordable service plans.

What is the AFUE?

It’s the is Annual Fuel Utilization Efficiency, a statistic that measures how efficient your heating system is. Consider it like your car’s MPG rating. The AFUE indicates the average amount of fuel consumed by your heating system when compared to how much heat it creates throughout a heating season. The AFUE is usually located on the faceplate of a boiler or furnace.

You can use the AFUE to comparison shop when purchasing a new furnace or boiler for your home.

This is how AFUE works: Let’s say you’re shopping for a propane furnace. You see one with an AFUE rating of 80. That means that an average of 80% of the propane it uses is converted into heat for your home. The other 20% is lost in the combustion and conversion process. Thus, 80 cents of every dollar you spend on propane goes toward heating.

Here is a guide from the United States Department of Energy on common AFUE ratings for furnaces. The current minimum AFUE standard for new heating systems is 80.

Low efficiency: This is mostly seen in older, outdated, and poorly maintained heating systems. The AFUE ratings fall between 56 and 70.

Medium efficiency: AFUE ratings are between 80 and 85. These are either new systems, or older systems less than 20 years old. Features include an exhaust fan controlling the flow of combustion air and combustion gases more precisely than older, low-efficiency systems, electronic ignition and not a pilot light, smaller size and weight that reduces cycling losses, and a small-diameter flue pipe.

High efficiency: This is most commonly seen in furnaces and boilers that are new or less than 10 years old. AFUE ratings are between 90 and 98.5. Their features include condensing flue gases in a second heat exchanger for added efficiency and sealed combustion.

Need a new heating system for your home? Contact P. Gagnon & Son for a FREE estimate!