Locating Air Leaks 8 - Attic Duct Sealing Locating Air Leaks 8 - Attic Duct Sealing

If Your Heating and Cooling Ducts Are in Your Attic, Seal Them While in the Attic.

Leaky and poorly insulated ducts (especially in attics) severely compromise the performance of your heating and cooling equipment. Sealing and insulating your ducts can increase the efficiency of your heating and cooling system by 20 percent and greatly increase air flow.

  • Check the duct connections for leaks by turning on your heating and cooling system fan and feeling for leaks - seal the joints with mastic or foil tape (household duct tape should not be used).
  • Pay special attention to all the duct penetrations going through the attic floor. Seal these with foam.
  • Ducts should also be insulated - If your ducts are uninsulated or poorly insulated (i.e. you see gaps or torn insulation) seal them first, then add insulation to keep the air in your ducts at its desired temperature as it moves through the system. Use duct insulation material rated at least R-6.

Material Checklist for Attic Duct Sealing

  • Mastic or foil tape
  • Duck insulation material rated at least R-6
  • Zip ties to hold duct insulation in place
  • Gloves, safety glasses, mask, flashlight

Caution: Check for Carbon Monoxide to keep your house safe. After making energy improvements that result in a tighter house, there can be an increased opportunity for CO to build up if your gas burning appliances are not venting properly. Have your heating and cooling technician check your combustion appliances (gas or oil-fired furnace, water heater, and dryer) for proper venting.

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