What does the Annual Fuel Utilization Efficiency Rating measure in a gas-fired furnace?

The Annual Fuel Utilization Efficiency (AFUE) rating measures the efficiency of a gas-fired furnace in converting fuel to heat over the course of a year. It is expressed as a percentage, indicating how much of the fuel energy is effectively used for heating compared to how much is wasted. A higher AFUE rating means that a furnace is more efficient, resulting in lower fuel costs and less environmental impact due to reduced emissions. This efficiency measurement is crucial for homeowners and HVAC professionals alike, as it helps assess the furnace's performance and informs choices related to energy savings and operating costs.

Other aspects, such as safety standards, maintenance frequency, and installation quality, do not directly pertain to the specific measurement of energy efficiency that AFUE represents.