Learn how to seal exposed ductwork in your furnace and air conditioner with these tips.
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Ductwork is the system in which conditioned air is transported to heat or cool your house. In an average home, up to 20 percent of that air is lost due to leaks, holes and faulty connections. Look for tiny holes in the tubing, gaps and branching lines of dust and dirt at duct connections. Most problems are found at the duct joints, duct connections and where ducts meet an air vent or floor register.
Below are signs your ductwork may need attention:
Ductwork can be hard to access. If you don't feel comfortable making repairs, contact a professional.
Wear eye protection when sealing ductwork. You’ll be working in dusty conditions and, in the case of sealant, brushing on liquids overhead. Wear disposable latex or nitrile gloves when using liquid sealant.
Vacuum ductwork where possible and wipe it clean with soapy water. Check for any loose fittings that can be tightened.
Apply the foil HVAC tape centered on the exposed seams in the ductwork. Use pieces long enough to wrap around the duct at each joint.
Press the tape in place using a plastic putty knife.
Use a foil-backed, UL-listed, tape with adhesive that resists heat damage and aging. Never use duct tape, it's not long lasting.
Vacuum ductwork where possible and wipe it clean with soapy water. If you find any gaps greater than 1/4 inch, fasten the pieces together again before applying sealant, or cover the gap with flexible mesh tape.
Beginning from the top or upper sides, brush sealant onto the ductwork over the joints. Coat the ductwork with bands about 2 inches wide and centered on the seams. Using the brush, work the sealant into the seam. Allow at least one day for the sealant to dry.
Make sure there's plenty of ventilation where you work. You can find solvent-based duct sealants, but a water-based product will give your nose and your house a break.
Ensuring your ductwork is properly sealed can: