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Furnaces

 

Function

  • A gas furnace passes cold air from a home over a burner to heat it. A blower then pushes the warm air into the ductwork of the house. The heated air comes out of vents inside the house, while cold air moves back to the furnace to be heated.

Efficiency

  • Modern gas furnaces can be up to 97 percent efficient. The average one is in the 80 to 90 percent range.

 

Furnace Efficiency Ratings

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Efficiency ratings indicate how much energy is used and how much is wasted. If a furnace is 80 percent efficient, for every $1.00 you pay in gas, you are getting only $.80 worth of energy. A 95-percent-efficient gas furnace can reduce your gas bills up to 20 percent in any given year. Tax credits are available (2009, 2010) for installing a 95-percent-efficient furnace.

 

Furnace Brands

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Some examples of brands of furnaces available include, Carrier, Bryant, and Payne. The heat exchanger is one of the primary components of a gas furnace and can be quite costly to repair or replace. If a heat exchanger goes bad and is out of warranty, it is recommended to replace the entire furnace because of the cost of repairing the heat exchanger. Selecting a furnace brand based on a good heat exchanger warranty is recommended.

Furnace Size

  • With furnaces, bigger is not better. If a furnace is too big for a house, the higher energy output of the oversized furnace will produce whistling noises in the vents. This in turn will result in higher utility bills, and the extra energy output will be wasted.
Important aspects of sizing a furnace for a house include the layout and design of the vents, square footage of the house, and how many floors, windows, skylights and doors it has.

 

Earning the ENERGY STAR means products meet strict energy efficiency guidelines set by the US Environmental Protection Agency. By choosing ENERGY STAR qualified heating and cooling equipment and taking steps to optimize its performance, you can enhance the comfort of your home while saving energy.

ENERGY STAR qualified furnaces have the following features:

  • Different gas furnace efficiency requirements and labels are used for different regions of the country.

Qualified gas furnaces in the southern half of the U.S., where homes require less heat, will be labeled with a unique “U.S. South” ENERGY STAR logo. These furnaces will be up to 12 percent more efficient than standard models and can save an average of $36 in energy costs per year.

Qualified gas furnaces in the northern half of the U.S. will be labeled with the standard ENERGY STAR logo. These furnaces will be up to 16 percent more energy efficient than baseline models and can save an average of $94 in energy costs per year.

Qualified oil furnaces are up to 4 percent more energy efficient than baseline models and can save an average of $66 in energy costs per year.