This Old House general contractor Tom Silva shows how to install a whole house fan.
Steps for Installing a Whole House Fan
- From inside the attic, take up any plywood floor covering the desired fan location.
- Lift out the insulation from between the ceiling joists.
- Cut two pieces of 2x10 to fit snugly between the ceiling joists. Set the blocks slightly farther apart than the length of the whole-house fan. Nail the blocking in place with 16d nails.
- Replace the plywood floor, fastening it to the joists with 1 5/8-inch drywall screws.
- Use a plunge router fitted with flush-cutting bit and guide bushing to cut out the plywood floor.
- Cut through the ceiling with a reciprocating saw, making sure someone stands below with a wet/dry vacuum to catch the dust.
- Fill the gap between the ceiling hole and attic insulation with spray-foam insulation. After the foam hardens, trim away the excess with a utility knife.
- Apply self-stick weatherstripping around the underside of the flange on the whole-house fan.
- Set the fan down into the hole, pressing it tight against the plywood attic floor.
- Secure the fan by driving 1 5/8-inch screws through its flange and into plywood floor.
- Attach the fan's grille from below.
- Plug the fan into a nearby outlet; if necessary, hire a licensed electrician to install an outlet close to the fan.
- Open the downstairs windows and any attic windows.
- Use the remote control to turn on the fan.