How to Install a Roof Power Vent

Preparing the Area

• 1

  Put the power vent fan together. Place the vent on the roof so that the top of the fan is level with the roof ridge where you are doing your placement. Measure the distance from the roof’s ridge to the fan’s center using a measuring tape. Go into the attic and find the center part of the roof. Measure down the backside of the roof until you can match the location of the fan.

• 2

  Put a couple nails through the roof to use as a guideline on the rooftop. Find the marker nails on the rooftop. Sketch a circle using a piece of chalk about 4 inches larger than stated in the instructions. Remove the roof shingles and the underlayment using a utility knife until you can see the wood sheathing.

• 3

  Draw a second circle the exact size specified in the instruction package. Cut the sheathing with a saber saw and if the hole is larger than the rafter distance, cut along the inner edges of the roof rafters, but don’t cut into the rafters.

Install Roof Power Vent

• 4

  Measure 6 inches above and below where the attic fan will need to cover the roofing and mark the area by hammering in about four nails. Pull up any obstacles that may stop the fan flashing from fitting underneath the shingles. Apply roofing cement underneath the fan flashing and roof sheathing to prevent leaks.

• 5

  Insert the fan housing under the shingles and align the fan housing with the hole in the roof. Hammer galvanized nails every 4 to 6 inches in the top and sides of the flashing. Attach the fan’s thermostat to the closest rafter that will not only allow easy access but also allow the sensing element to be exposed to air. Place the sensor away from the fan.

• 6

  Feed a 12-gauge copper cable through the wall to a junction box. Turn the power off at the main breaker. Drill a ¾-inch hole over the receptacle junction. Remove the junction box. Feed the cable through the hole and into the receptacle. Attach the cable to the electrical receptacle and connect to the thermostat. Secure the cable with staples.

• 7

  Connect the wire leads to the wires of the thermostat’s wiring box, being sure to match wire colors and place wire nuts on the ends. Connect the ground wire cable to the ground screw. Wire in a humidistat for automatic operation or bypass the thermostat and humidistat to turn the fan on or off manually.