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What is AFUE - Annual Fuel Utilization Efficiency
- AFUE, DEFINITION - CONTENTS: Definition of AFUE - Annual Fuel Utilization Efficiency rating of heating equipment such as boilers, furnaces, and water heaters. Determining heating boiler or furnace capacity & energy efficiency; how is heater efficiency measured, what is the AFUE rating?
- POST a QUESTION or READ FAQs about AFUE and heating system efficiency ratings, measurement, and improvement
This article gives a definition of AFUE and explains AFUE (Annual Fuel Utilization Efficiency) or heating system efficiency ratings and numbers.
The articles at this website describe the basic components of a home heating system,
how to find the rated heating capacity of an heating system by examining various data tags and components, how to recognize common heating system operating or safety defects, and how to save money on home heating costs.
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How is heating boiler efficiency or economy measured? What does boiler AFUE mean?
How is heating boiler efficiency or economy measured? What does boiler AFUE mean?
In short, the AFUE (Annual Fuel Utilization Efficiency) tells you,
for each dollar you spend on energy for heating by gas, oil, or another fuel, just how much of your dollar shows up inside the occupied space of your building as heat.
Here's a very rough example: if the AFUE number for your heater is 80%, that means that for every dollar you spend on heat, twenty cents "goes up the chimney" or is lost in various other ways, and eighty cents of each heating dollar shows up in your occupied space as heat.
[Click to enlarge any image]
Each model of heating boiler or furnace is assigned an AFUE number. Our page top sketch of a high efficiency furnace is provided courtesy of Carson Dunlop Associates.
At left we illustrate a high efficiency gas furnace - expected to have a high AFUE number. Sketch courtesy of Carson Dunlop Associates.
Also see this sketch of a high efficiency condensing furnace and this high efficiency pulse combustion heating system.
AFUE is an abbreviation for Annual Fuel Utilization Efficiency. In short, the AFUE tells you, for each dollar you spend on energy for heating by gas, oil, or another fuel, just how much of your dollar shows up inside the occupied space of your building as heat. Higher AFUE is better.
If your boiler or furnace or steam boiler has an AFUE rating of 90, that means that for every dollar you spend on fuel, 90 cents worth of heat is delivered into your building. The remaining 10 cents is lost in inefficiency such as heat that escapes up the chimney along with the products of combustion.
What is the Reliability & Accuracy of Heating System Efficiency Ratings - AFUE?
AFUE is not the whole story of heating cost efficiency. A high-efficiency heating system that has not been cleaned and serviced may be running poorly and wasting money.
In fact, an 85% AFUE heating boiler that has not been cleaned might be running at an efficiency much lower, perhaps 65%.
Furthermore, if your building is drafty or poorly insulated, you may be delivering heat at high efficiency but losing it from the building much faster than necessary.
These articles can help with a more complete approach to saving money on heat:
What are the Current AFUE Requirements for Heating Equipment?
- In the United States, the U.S. Department of Energy has specified that currently all heating furnaces sold in the U.S. must have an AFUE of 78% or better.
- In Canada, National Resources Canada (NRC) as of 2009 specifies that gas furnaces manufactured after 31 Decemb23 2009 must have an AFUE of 90%. Kudos to the Canadian NRC.
Other Heating System Performance Measurements & Standards
Also see our definition of HSPF, SEER, and other measurements found at SEER RATINGS & OTHER DEFINITIONS [live linke just below] or select a topic from the More Reading links shown below.
Continue reading at APPLIANCE EFFICIENCY RATINGS or select a topic from the More Reading links shown below.
Or see DEFINITION of HEATING & COOLING TERMS
Or see SEER RATINGS & OTHER DEFINITIONS
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AFUE DEFINITION, RATINGS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.
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- Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 email@example.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides:
- Commercial Building Inspection Courses - protocol ASTM Standard E 2018-08 for Property Condition Assessments
- Home Inspection Education Courses including home study & live classes at eleven colleges & universities.
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Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
- The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
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