Glossary term
AFUE (Annual Fuel Utilization Efficiency)
The percentage of fuel a furnace converts into usable heat over a typical year. An 80% AFUE furnace turns 80 cents of every $1 of gas into heat; the other 20 cents leaves through the flue.
What this means in Kansas City
Federal minimum for new gas furnaces sold in the U.S. is 80% AFUE for non-weatherized residential units in the southern region and 95% AFUE in the northern region. Most KC-metro replacements land at 95–97% AFUE for a meaningful gas-bill drop on a 15+ year-old furnace.
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