How to Install Insulation Around Vent Returns

Although you do not usually insulate the ductwork that returns to your furnace from your vents, a few cases might arise where insulation proves beneficial. For example, if your return air ductwork runs through an unheated space like a crawlspace or attic, you need to insulate it. Otherwise, the air will cool significantly as it travels back to the furnace and your heating bills will rise. Depending on your climate, you might recoup the cost of insulating the ductwork within just a few months.

Tape measure
Dust mask
Safety glasses
Duct insulation
Utility knife
Foil tape
Plastic squeegee (optional)

Instructions

- 1
  Measure all four sides of the ductwork. Add these measurements together to find the perimeter.
- 2
  Put on a dust mask and safety glasses.
- 3
  Unroll the duct insulation on the ground. Add approximately 6 inches to the perimeter measurement; this provides an allowance for the thickness of the insulation. Cut the duct insulation at this measurement with a utility knife.
- 4
  Fit the duct insulation around the ductwork. Ensure the insulation faces toward the ductwork and the foil faces away. Tape one end of the insulation to the ductwork with foil tape.
- 5
  Pull the other end of the duct insulation tight until it slightly overlaps the place where you taped the first end to the ductwork. Secure this end with foil tape. You should see only the foil facing of the duct insulation at this point.
- 6
  Cut successive pieces of duct insulation and secure them in the same manner as above. Tape all seams with foil tape. This includes the seams where each section of duct insulation meets the next.

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