What is the purpose of the AFUE rating?

The AFUE rating, which stands for Annual Fuel Utilization Efficiency, specifically measures how efficiently a furnace converts the energy it consumes into usable heat for a home or building over the course of a year. It is expressed as a percentage, indicating the ratio of the heat output as compared to the energy input. For instance, an AFUE of 90% means that 90% of the energy consumed by the furnace is converted into heat, while the remaining 10% is lost, often through flue gases.

This rating is closely associated with the evaluation of heating system performance and plays a crucial role in aiding consumers in selecting the most energy-efficient furnace for their needs. A higher AFUE indicates more efficient operation, which translates to potential energy cost savings and better environmental performance.

In contrast, measuring noise levels pertains to other metrics not related to AFUE, energy consumption of electrical appliances falls under different assessments, and calculating overall building insulation performance involves methods distinct from those used to evaluate furnace efficiency. Thus, the AFUE rating is specifically focused on heating performance rather than these other aspects.