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Kilowatt Heating, Air Conditioning and Electrical Blog

What Makes High-Efficiency Furnace So… High Efficiency?

IMG_8221Two weeks ago we posted about replacing old floor furnaces with safer and more energy-efficient units. In general, older natural gas furnaces—regardless of type—are wasteful of energy compared to newer ones. The AFUE ratings of furnaces from more than a decade ago range between 60% to 80%, which means they waste between 20% to 40% of their energy when generating heat. New, high-efficiency furnaces, however, can achieve remarkably high AFUE ratings. Some ENERGY STAR-certified furnaces have AFUE ratings of 97%, which means they waste only 3% of the energy they use. The rest go straight to generating heat.

How is the miracle possible? For one thing, newer furnaces are simply better constructed. But there are a number of specific technological advances in high-efficiency furnaces that makes them superior at using their energy supply:

  • Second heat exchanger: The new condensing furnaces use a second heat exchanger to squeeze as much thermal energy as possible from the combustion gases. The vapor left over in the first heat exchanger is sent to the second exchanger rather than being exhausted to the outside. The second exchanger condenses the vapor, releasing even more heat.
  • Variable-speed fans: A standard furnace has a fan that runs at a single speed. A variable-speed fan in a furnace allows the furnace to continue to keep working at distributing air, but at a less energy-consuming level. You don’t have to worry about setting the fan yourself; the furnace will automatically change the fan speed to match the house’s heating requirements.
  • No more standing pilot lights: A pilot light that burns throughout the summer will drain extra energy. Newer furnaces have exchanged these pilot lights for electronic ignition systems that turn on only when it’s necessary to light the burners. This mean less energy used throughout the season.

Interested in installing a new gas furnace in Valley Village, CA? Then call Kilowatt Heating, Air Conditioning and Electrical today.

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