How to Insulate Louvers for Whole House Ventilation Fans

How to Insulate a Whole House Fan from the House Side

• 1

  Cut a piece of 1-inch or thicker insulation board (EPS or similar material with smooth, flat faces) to match the perimeter of the fan unit, using a sharp utility knife and straightedge.

• 2

  Cover the front (bottom) face of the insulation board with contact paper in a color and style that blends with your ceiling. If desired, run the paper long so it covers the edges of the board.

• 3

  Apply a square of Velcro tape at each corner on the back (top) face of the insulation board, then apply the mating sides of the tape to the corners of the fan unit. Apply soft foam weatherstripping along the perimeter of the board, between the Velcro pieces. Stick the board into place, making sure the weatherstripping creates a complete seal with the fan unit (or ceiling surface, as applicable).

• 4

  Label the wall switch controlling the fan with a warning: “Remove cover before running fan.”

How to Insulate a Whole House Fan from the Attic Side

• 5

  Cut pieces of 1-inch or thicker insulation board (EPS or similar material with smooth, flat faces) to create a box that fits over the top side of the fan unit, using a sharp utility knife and a straightedge. The sides of the box should fit flush to the unit itself or to the wood framing surrounding the unit, as applicable.

• 6

  Assemble the box with construction adhesive. Apply the adhesive in continuous beads to create a complete air seal at all joints. Let the adhesive dry.

• 7

  Fit the box over the fan unit. If necessary, you can add foam weatherstripping along the perimeter of the fan (or framing) to improve contact with the box for a better air seal. Label the wall switch controlling the fan with a warning: “Remove cover before running fan.”