Annual Fuel Utilization Efficiency AFUE
AFUE, or Annual Fuel Utilization Efficiency, is a measure used in the United States to show how efficiently furnaces, boilers, and space heaters convert fuel into usable heat. Set by the U.S. Department of Energy, the rating works on a simple rule: the higher the percentage, the more efficient the appliance. Heating products sold in the U.S. must meet a minimum AFUE of 78%. Each appliance displays its AFUE on a yellow Energy Guide label for customers to compare.
AFUE is calculated by dividing a boiler’s total annual heat output (in BTUs) by its total annual energy input (also in BTUs) and multiplying by 100. In practice, measuring AFUE is quite technical because it requires sensors and equipment to track heat output over time. Once the total yearly heat output is known, it is compared to a standard figure of 100 million BTUs, which represents the typical fuel needed for a heating season.
[edit] Related articles on Designing Buildings
Featured articles
Check out some of the best features and news from Designing Buildings as well as key stories from around the web.
Guidance for conversion of traditional pre-1919 stone buildings.
Industrial heritage in the Ruhr
A marked difference to the fate of industrial landscapes in the UK.
Communities will be able to build their own clean energy.
Why diversity and inclusion matters for SMEs
CIOB’s D&I Charter shows how practical changes can support long-term growth.
Cut electricity bills to power growth
Coalition sends joint letter to the Chancellor.
Gasholders: a history in pictures. Book review.
Recognition, influence and growth
SocEnv identifies three strategic pillars in new strategy to 2045.
Discover the future of roofing, cladding and insulation.
New guidance for professional practice, cultural change and regulation in social housing.
The heritage of nuclear and conventional power stations.
New measures to stop people being ripped off
Government to protect families from cowboy builders and aggressive bailiffs.
New Futurebuild showcase brings an innovation-first approach.