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Common Questions About Heating, Ventilation and Cooling
What is an AFUE rating for a furnace?
The AFUE rating system was designed with efficiency in mind. AFUE is the acronym for Annual Fuel Utilization Efficiency. An AFUE rating is a very telling piece of information on gas furnace labels. It tells us the relationship between the heat output of a furnace to the entire energy consumed by that furnace.
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As mandated by the U.S. Federal Trade Commission, all new gas furnaces must have an AFUE rating somewhere in a visible spot so that consumers can compare ratings among different models. The AFUE rating is based upon how energy efficient a furnace is over a time period of one year.
A higher AFUE rating for a furnace indicates that less fuel will be needed to heat a building. These gas furnaces are pricier, but worth the extra cost in the long run. Over time, a furnace with a higher AFUE rating saves money by having a lower operating cost than a model with a lower AFUE rating.
When you go to the store to purchase a gas furnace, you’ll see AFUE ratings of varying percentages. These percentages indicate how energy efficient the furnace is. For example, if a furnace has an AFUE rating of 85%, then that means 85% of the fuel in the furnace will effectively become energy that heats a building. The other 15% of the fuel doesn’t go toward heating the building; instead, it escapes through another avenue, like the chimney.
The AFUE rating doesn’t give us the complete picture, though. The rating does not factor in the percentage of heat that may escape due to a faulty duct system or piping problem. When looking for an energy efficient furnace, check for a model that has an AFUE rating of at least 90%, a sealed combustion, and a condensing system. The sealed combustion keeps gas from the furnace from being blown inside the building. A furnace with a condensing system costs more to purchase, but needs less fuel to operate, therefore saving you money in the long run.