Which rating is used to determine the efficiency of gas-burning appliances?

The Annual Fuel Utilization Efficiency (AFUE) rating is specifically designed to measure the efficiency of gas-burning appliances, particularly furnaces and boilers. AFUE indicates the percentage of fuel that is converted into usable heating energy over the course of a year, taking into account factors like heating output versus energy input. A higher AFUE percentage signifies a more efficient appliance, meaning it can produce more heat for the same amount of fuel consumed.

For example, an AFUE rating of 90% means that 90% of the energy from the fuel is utilized for heating, while the remaining 10% is lost, typically through exhaust or other inefficiencies. This metric helps consumers assess the long-term operational costs and environmental impacts of gas appliances, making it a critical standard in selecting efficient heating systems.

Other ratings, like the Seasonal Energy Efficiency Ratio (SEER) and the Energy Efficiency Ratio (EER), are tailored for cooling equipment, not heating appliances, and the Coefficient of Performance (COP) is used primarily in heat pumps. Thus, AFUE is the correct rating for evaluating the efficiency of gas-burning heating appliances.