Watch the video on Preventing Ductwork Condensation.
Everyone's familiar with the scenario—it's Monday morning, and you're running late for work. You hastily jump in your car, and glance through your rear view mirror only to find that your window is glazed over with condensation, blocking your rear view. While this moisture doesn't cost you more than a couple minutes of wiping off your window, condensation that forms on ducts in the attic can create severe problems in a home.
Any time warm air meets a cold surface you can expect condensation. When attics heat up like ovens in the summertime, condensation can form on the cold air conditioning ducts. Once this condensation collects, it can drip onto ceiling drywall, attic insulation, lights, registers and grilles in the home and can lead to staining, rusting, and even mold growth.
To prevent problems caused by condensation building up on ductwork, the best practice is to locate ducts and HVAC systems in conditioned spaces, like the basement. But if you have no choice but to install ducts in the attic, insulating the duct system is the preferred solution. Insulating ducts early in the construction process saves homeowners from costly upgrades and repairs later on.
To insulate ducts, you'll want to use one of the following insulating strategies:
Enclose sheet metal ducts in duct wrap: Composed of fiberglass and a vapor retarder, duct wrap covers the exterior of the duct to warm its surface and prevent condensation. The vapor retarder limits the amount of moisture passing through the insulation to the duct. Duct wrap is available in R-values of 4, 6, and 8.
Before you insulate ducts with duct wrap, be sure to seal the joints with mastic to eliminate air leaks; sealing joints ensures that air will flow through the ducts at maximum speed without leaking and maintain a consistent temperature, saving energy and preserving the insulation.
Use a system of fiberglass duct board and flex duct: This duct system, which is superior to sheet metal ducts, includes built-in insulation. Duct board and flex duct create an airtight, durable, quiet duct system when installed properly. Be sure to follow best practices for connecting duct board and flex duct to ensure energy efficiency. Review the Sheet Metal and Air Conditioning Contractors' National Association's (SMACNA) Fibrous Glass Duct Construction Standards, available at www.smacna.org.
Preventing moisture isn't the only advantage to installing insulated duct systems. Insulated ducts also improve the energy efficiency of the home, reducing the burden on the home's HVAC system and on homeowners' wallets.
To learn more about insulating ducts, visit:
www.owenscorning.com
www.ibacos.com
Related:
Central Return Duct System
How to Steal Ductwork
Ducts in Conditioned Space
Preventing Condensation on Ductwork
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