What Are Furnace Ratings?

What are furnace ratings? Every year, the Annual Fuel Utilization Efficiency (AFUE) rates furnaces: the percent of heat produced for every dollar of fuel consumed. Like the miles per gallon on your car, the higher the AFUE rating, the lower your fuel costs. All furnaces manufactured must now meet at least 78% AFUE. If your furnace is 10 to 15 years old, it probably falls well below the current furnace minimum and wastes energy.

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Isolated Combustion System (ICS): A New Rating

In 1989, the U.S. Department of Energy (DOE) adopted a new, fair way to rate furnaces for AFUE efficiency. The Isolated Combustion System (ICS), the updated industry standard, reflects the efficiency of a furnace installed in a home setting.

  • What does the AFUE rating mean?: The AFUE rating shows the efficiency of a particular furnace. Your contractor can determine the potential cost savings of your fuel costs, annual usage, and efficiency. The AFUE rating provides consumers with one consistent number for comparison. Essentially, the ICS test compares “apples to apples.” That is, all furnaces are tested equally. Manufacturers determine AFUE ratings by testing furnaces under set conditions for various lengths of time. The conditions were determined by the DOE to simulate an average home setting. So even though your furnace may not be installed in your home exactly like it is installed in the test lab, since all manufacturers must comply with the same testing procedures, the ICS rating is still the best way to compare furnace efficiencies.
  • Can I just look for a furnace with a high AFUE rating?: Not exactly. The efficiency rating is just one factor to consider when looking at new fans and motors. The amount of electricity used varies greatly, depending on the type of furnace. Be sure to check electricity usage before making a purchase decision. In addition, you will need to consider many other factors like the following:
    • How long do you plan to live in your home
    • Special comfort needs
    • Fuel availability
    • Fuel cost
    • Geographic area and climate

Adding up all these factors, along with your lifestyle and family needs, will show you which system is best for you. To find the best furnace for your home, contact Long Heating and Cooling today.