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Don't Let Unsealed Ducts Waste Your Energy and Money


Your ductwork does an important job of distributing your heated and cooled air throughout your home. Over time, ducts are subject to wear and tear as they expand and contract under the pressure of the heated and cooled air that travels through them.

As they age, the metal wears down and segments come unsealed. Ducts may also be damaged when construction or maintenance work occurs in the space where they are located, or from insects or rodents.

Whenever the integrity of the ducts is compromised, you lose energy and waste money. Eventually, you will need to know how to perform duct sealing or hire someone to do it.


Your HVAC ducts are generally located in unconditioned spaces such as the garage, attic, basement or crawl space. When they develop cracks or tears, or segments come apart, your conditioned air leaks out and unconditioned air can get into your supply air. This not only compromises your heating and cooling efforts, but also introduces humidity and pollutants into your home. When you keep your ducts properly sealed, you eliminate problems associated with the following:

Indoor air quality— Duct sealing keeps pollutants and humidity out of your supply air.

Comfort— Uneven cooling and heating can occur when ducts are not sealed.

Safety— Back drafting from the ventilation systems of gas appliances such as furnaces, water heaters and clothes dryers can occur when ducts are unsealed.

Higher utility bills— Leaking ducts may reduce cooling and heating efficiency by as much as 20 percent.

Environmental concerns— The more energy we use, the more carbon emissions are produced at power plants. Efficient practices such as duct sealing help lower your carbon footprint.


Sealing ducts is a fairly straightforward do-it-yourself project. Reconnect loose segments by using metal tape, mastic sealant and metal screws. You can also repair holes and cracks with these materials. Never use duct tape, as it deteriorates quickly.

Would you like more information on duct sealing? Visit the Valley Heating, Cooling, Electrical website for in-depth information on most HVAC topics or give us a call at (408) 868-5500.

Our goal is to help educate our customers in the South Bay Peninsula and Santa Cruz areas of California about energy and home comfort issues (specific to HVAC systems).

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