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Sealing & Insulating Ducts - Alternative to Zoning (Part 1)
In a previous post, we talked about zoning: creating separate thermostatically-controlled areas within your home to help even out the hot and cold spots. Although zoning can save you up to 30% in energy costs, it is not without cost itself. Suppose you don’t want the expense of replacing your current system with a new multi-zoned HVAC unit, or re-working your current ductwork layout to accommodate a retrofit. Never fear! There are lots of things you can do to address and possibly alleviate the uneven temperatures in your home. In this post (the first of a 3-part series), we'll focus on how sealing and insulating ducts may help.
Step 1: Seal the ducts
Ductwork is used to distribute the heated or cooled air throughout your home. In a typical home, 20-30% of the air in the ductwork is lost due to leaks, holes, and poor insulation. The result is difficulty keeping the house comfortable no matter how the thermostat is set. Check the ducts in your attic, crawl space, and basement, and look for holes or gaps, areas where the ductwork has been crushed or kinked, or has become disconnected. Repair and seal the holes using mastic sealant or metal-backed (foil) tape – NOT the typical grey fabric duct tape! Contrary to its name, “duct tape” is not the best solution for sealing ducts. Cloth-backed utility tapes are not recommended because they will fall off easily, degrade with extreme heating and cooling, and do not reflect heat. Look for aluminum-backed tape with the Underwriters Laboratories (UL) logo. Duct mastic is the preferred material for sealing ductwork seams and joints, especially irregular or jagged edges.
Step 2: Seal Registers & Vents
Check all the air register vents in each room, and the return air grill, to ensure there is a tight seal between the duct opening and the grill, that there are no tears in the ductwork from debris falling inside the register, and that the duct has not torn away from the opening.
Step 3: Insulate the ducts
Insulate the ducts, especially in the attic where the temperatures soar in the summer, and in the crawl space and basement where the temperatures are coldest in the winter. Wrap all ducts with foil-faced fiberglass insulation having an R-6 value or greater and seal the joints with foil-faced duct tape.
Prefer a hands-off approach to your ductwork? If you live in the Nashville and surrounding area, call on Interstate AC Service at 615-832-8500 to help with ductwork repair, or whatever heating and cooling issues you may have. We’re here for you!