June 2005
Leaky Ductwork Raises Your Energy Bill

High energy bill? Your ductwork could have leaks. Check your home's ductwork for leaks.

Leaky ducts can waste up to one-third or more of the heating your system produces. You could be paying one-third more to heat your home than you would pay if your ducts were properly sealed.

The duct system distributes heated and cooled air throughout your home. But leaks allow air into unwanted places. Air can escape from the ductwork into attics or crawl spaces, so you end up paying more to heat or cool those unintended areas.

Sealed ducts promote better air quality for your home. Ducts are generally placed in crawl spaces, attics or basements. If the return ducts leak, air can be sucked in from these areas and distributed throughout the living space of your home. This allows dust, mold and other undesirable particles to pass through the ductwork.

If the ductwork's joints are installed according to energy codes, the chances of leaks are minimal. Insulated ducts do not prevent leaks. Ducts can be adequately insulated, but if they're not sealed properly, air can still escape.

R-6 duct insulation is the recommended R-value for insulating ducts. If possible, ductwork should be installed in conditioned areas of your home, the crawlspace or basement. Attics are less desirable areas because of the excess heat during the summertime.

Some homes' ductwork isn't sealed at all. When poor quality materials are used to seal ductwork, the likelihood of leaks increases. Common duct tape doesn't sufficiently protect against leaks.

How can you tell if your ductwork has leaks? Not all leaks are visible. New or existing homes can have leaks.

Several signs indicate leakage. Look for dirt streaks along parts of the insulation. Also, some rooms may be too cold or too hot due to inadequate air distribution. You should be able to feel a difference in room temperature of rooms not properly ventilated.

Place your hand close to the ductwork to feel for air blowing out or being pulled into the ductwork. Be careful not to rub your hand against the metal to prevent cuts.

A certified heating and air contractor can test your system for leaks. A contractor can conduct a pressure test using a blower door. Using a special fan, the contractor blows air into the ducts to define the amount of leakage and the location of leaks.

Contractors can also use an infrared thermometer to test the temperature of areas throughout the ductwork.

Sealing ductwork doesn't have to cost a fortune. To permanently seal duct materials, combine a fiberglass mesh and mastic to permanently seal all duct materials. Mastic is an inexpensive paste sold in tubes or gallon tubs at home improvement stores.

Improve your ducts' efficiency at low costs. To learn more about ductwork systems, log on to the U.S. Department of Energy's consumer information website and search "ductwork."

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This month's recipe features Karl's Killer Brownies.