The efficiency rating of a gas furnace is measured by what rating?

The efficiency rating of a gas furnace is measured by the Annual Fuel Utilization Efficiency (AFUE). The AFUE percentage indicates how much of the fuel consumed by the furnace is converted into useful heat for the home, providing a clear metric of how efficiently the furnace operates over the course of a year. For example, an AFUE rating of 90% means that 90% of the fuel is used effectively for heating, while the remaining 10% is lost in exhaust or other inefficiencies.

In contrast, SEER (Seasonal Energy Efficiency Ratio) is specific to air conditioning systems. It measures cooling efficiency over a typical cooling season, not applicable to gas furnaces. ENERGY STAR is a certification program that recognizes energy-efficient products and practices but does not assign a specific measurement rating like AFUE does. EER (Energy Efficiency Ratio) relates to the efficiency of cooling equipment, similar to SEER but measured at specific conditions rather than over a season.

Understanding AFUE is essential for evaluating the heating performance of gas furnaces and comparing different models to ensure energy efficiency and cost-effectiveness in home heating.