How Does the AFUE Rating Affect My New Heater?

If you’re in the market for a new heating system, now is the time to consider it. September and October are still fairly warm months here in Brea, CA, giving you an excellent window to select a new system and have it installed before you have need of it. Among the factors you need to look for is overall efficiency, which is measured with a percentage known as AFUE. The term stands for Annual Fuel Utilization Efficiency, and after the overall power levels of the furnace, it’s the most important element in choosing a new furnace.

How It’s Derived

The formula for deriving the AFUE rating is fairly easy: it measures the amount of energy put into the system (measured in British Thermal Units or BTUs) against the heating power it puts out. So a system with an 80% AFUE rating would generate 80% of the heating power that it consumes in energy, while one with a 90% AFUE generates 90% of the heating power that it consumes. (The rest is lost to waste and general inefficiency.) The efficiency is measured over time (annually) to account for variations from day to day, creating a more accurate estimation of how well the furnace functions.

Balanced Against Power Levels

Obviously, you want a high AFUE for your new furnace, but it needs to be balanced against the overall power levels of the system. If, for example, you bought an under-powered furnace with a higher AFUE rating than one properly sized for your home, you will lose the benefits of the added efficiency since the furnace must work harder to adequately heat your home. Let the installation technician measure your home to determine the proper power levels (using your old furnace as a starting point, ten factoring in specifics to your home such as insulation and sunlight exposure), then select the unit in your size with the highest AFUE you can afford.

Call JC Mechanical Inc. to learn more!

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