The ABCs of Home Heating – AFUE Ratings

When purchasing a new central furnace, it's essential to know how efficiently it can convert the energy from natural gas into heat. This is calculated by the annual fuel utilization efficiency or AFUE. All new furnaces sold in the U.S. are required to display an AFUE rating so consumers can compare how efficient different models are during a typical heating season.

AFUE is the ratio of the annual heat a furnace produces compared to its fuel consumption. So, an AFUE of 90% means that 90% of the energy in the fuel is converted to heat while the remaining 10% is dissipated through the exhaust and other inefficiencies.

It's important to understand that AFUE ratings do not account for all the heat lost through the home's air duct system and other inefficiencies, which can be as much as 35% of total energy loss. For this reason, when upgrading your heating and cooling system, you should have an HVAC technician check your home's ventilation system to ensure it is not reducing overall operating efficiency.

Have questions about furnace efficiency or other heating questions? Call ABC Plumbing. We're here to help.