The annual fuel utilization efficiency is a thermal efficiency measure of space-heating furnaces and boilers.

What is a good AFUE rating?

WHAT IS A GOOD AFUE? A higher AFUE rating means greater energy efficiency. The minimum standard AFUE for new furnaces is 78 percent. A mid-efficiency furnace usually has an AFUE rating between 80 and 85 percent, while a high-efficiency unit has a rating between 90 and 97 percent.

Is 80 AFUE good?

High-efficiency furnaces offer 90% AFUE and higher, with 95% AFUE a common percentage for a new gas-powered furnace. An 80% AFUE is considered a standard efficiency.