How to Insulate Heat Ducts
Heat ducts transfer warm, heated air from the furnace to the HVAC grilles. The air then disperses into the space the heat ducts are intended to heat. Metal is a conductor of heat and the main material of heat ducts. If the duct work is not insulated, the warm, heated air will get significantly cooler before it reaches the HVAC grilles. This is especially true if the duct work passes through unconditioned spaces like crawlspaces or attics. When you insulate heat ducts, the heated air makes it to the HVAC grilles without a significant loss of temperature. Does this Spark an idea?
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Things You'll Need
- Tape measure
- Calculator
- Utility knife
- Duct wrap
- 3-inch foil aluminum tape
- Stapler
- Staples
- Dust mask
- Safety glasses
Instructions
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1
Measure the perimeter of the duct work if it is square or the circumference of the duct work if it is round. Calculate the perimeter by adding all the sides of the duct, and calculate the circumference by multiplying the diameter of the round duct by pi (3.14). For example, a 12x10 duct would have a perimeter of 44 inches, and a 10-inch round duct would have a circumference of 31.4 inches.
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2
Take the measurement from step 1, and add 6 inches to it to account for the thickness of the insulation and overlap allowance. If you had a perimeter of 44 inches, your new measurement will be 50 inches. If you had a circumference of 31.4 inches, your new measurement will be 37.4 inches.
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3
Roll out your duct wrap insulation on the floor. Cut off a piece at the above measurement with a utility knife.
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4
Wrap the insulation around the duct with the foil, face-side up. Pull it tight, and tape the seam together with 3-inch foil aluminum tape.
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5
Continue cutting pieces of insulation and installing them on the heat duct. Tape all seams with 3-inch foil aluminum tape.
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1
Tips & Warnings
For a more secure hold, staple the seams together before taping them. This will provide a little extra strength in case the tape begins to degrade over time.
Wear a dust mask and safety glasses when working with fiberglass duct insulation. Inhaling insulation particles or getting them in your eyes can be harmful to your health.
