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Why You Should Seal Your Ducts Before Winter

Why You Should Seal Your Ducts Before WinterDuct sealing in winter is critical to ensure your furnace heats your home’s living spaces — and not some other part of the structure. Ductwork leakage is one of the top three causes of reduced HVAC efficiency. Here’s why it’s a major problem:

  • Air leaking out of supply ductwork is wasted energy, as the warmth escapes into the attic, crawl space, or inside walls, where it contributes nothing to indoor comfort. This means chronic cold spots inside the house.
  • Leaky ducts cause your furnace to run longer cycles to compensate for the lost heat, boosting monthly heating bills.
  • Leakage in return ducts sucks unfiltered air into the system from internal areas of the house structure, which may be contaminated by dust, insulation fibers, mold spores, and other airborne particulates.

Nationwide, leakage from residential ductwork averages about 30%, but in some homes, it may be as high as 75%. For existing houses, most experts recommend sealing ducts to keep leakage from going above 10%. This minimizes heat loss as well as compromised indoor air quality. Here are some specifics about duct sealing in winter to help you achieve that goal:

  • How much heat is leaking? A duct-pressure test performed by a qualified HVAC contractor can be utilized to calculate the exact amount of air loss in order to estimate the extent of leaks in the system.
  • Where are leaks located? Because most of the total span of ductwork inside a home is routed through inaccessible areas, a contractor uses special devices and techniques to look inside ducts for deterioration, as well as for issues such as loose joints between duct spans.
  • How are leaks sealed? If joints are leaky, they are sealed with mastic to prevent leakage, taped, and secured with screws. The interior surfaces of the ducts may also be coated with an aerosol sealant injected into the ductwork to eliminate pinhole leaks throughout the system. Where severe corrosion or deterioration is encountered, that span of ductwork may be cut out and replaced.

For more information about the comfort and efficiency benefits of duct sealing in winter, contact the professionals at Beyer Boys.