What does an AFUE rating indicate for furnaces?

An AFUE (Annual Fuel Utilization Efficiency) rating indicates how efficiently a furnace converts fuel into heat over a typical year. This rating is expressed as a percentage, showing the ratio of heat output from the furnace compared to the total energy input in the form of fuel. For example, a furnace with an AFUE rating of 90% means that 90% of the energy in the fuel is turned into heat for your home, while 10% is lost in the combustion process and venting.

This metric is crucial for consumers because it helps them compare the energy efficiency of different furnace models, enabling informed decisions based on operating costs and environmental impact. An efficient furnace can lead to significant savings on energy bills and reduced greenhouse gas emissions, making AFUE a vital factor in evaluating heating options.