AFUE is the acronym for Annual Fuel Utilization Efficiency. AFUE is a rating that reflects how efficiently a gas furnace converts fuel to energy. The higher the AFUE, the more efficient the unit is at heating your home. That’s good for your wallet.

AFUE = (Total annual heat output in BTUs / Total annual energy input in BTUs) x 100

An AFUE rating of 90 means that the furnace utilizes approximately 90% of the fuel to provide warmth to your home, while the remaining 10% escapes as exhaust. 

A standard efficiency furnace has an AFUE of around 80%. A high-efficiency furnace has an AFUE of 90% or higher. Higher-efficiency furnaces will cost more upfront, but the increased efficiency may result in lower utility bills.

Browse furnaces.

We’re here to help

Connect with our Customer Care team about your products, warranties, and dealer concerns.

Available Monday – Friday from 7am to 5pm CST


A phone

Contact a local dealer

Dealers can answer questions, help you find the right products for your home, and repair your system.

By pressing “submit,” I consent to be contacted about products and services from a local American Standard dealer at the information provided. See our Privacy Policy for more information.