An energy-efficient furnace can provide healthier air, limit the release of harmful pollutants into the environment and significantly reduce energy costs. But how do you know if your furnace operates efficiently? The Federal Trade Commission (FTC) uses a measurement called annual fuel utilization efficiency (AFUE) and requires the measurement to be disclosed on all new furnaces.AFUE is a ratio that measures how much of the fossil fuel energy consumed by the furnace is actually used to generate hot air. For example, a furnace with an AFUE of 85 means that 85 percent of the fuel used by the furnace turns into heat inside the home. The remaining 15 percent escapes through the home’s chimney, ducts or other vents.

The current minimum efficiency rating for furnaces in the U.S. is 78. However, starting on January 1, 2015, most new furnaces will be required to operate at 80 percent efficiency, and new furnaces installed in homes in the northern United States will be required to have a 90 percent efficiency rating.

If you have an older furnace in your home, you may not be able to find its efficiency rating. However, some of the furnace’s features could give you a clue. If your furnace is older and uses a continuous pilot light and a heavy heat exchanger, then it may be a low-efficiency unit with a rating between 56 and 70 percent. If your furnace is newer and has a second heat exchanger and no pilot light, then it could be a high-efficiency unit with a rating between 90 and 98 percent.

Generally speaking, high AFUE furnaces reduce energy costs. How much the costs drop depends on how big your home is, how well air circulates in your house and what temperature you set on the thermostat. It’s a certainty, though, that a furnace with a high AFUE will require less fuel to produce the same amount of heat as a low efficiency unit.

For more information about AFUE ratings or other home comfort concerns, contact the pros at Rheem Pro Partner.

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