Press "Enter" to skip to content

How to install an attic ventilation fan

Signs that an attic does not have adequate ventilation include roof tiles with curled edges or protuberances. Attic air extractors remedy this situation and also help the hot penthouses cool in the summer. The installation of an attic air extractor will improve the project that normally only occur between the soffit and the ceiling ventilation flange. In, the total size of the general attic of ventilation, including the fan, should be equal to 1/300 of the attic floor size. The installation of an outdoor vent in the opposite gable as the exhaust-fan attic will increase the efficiency of the fan.


  1. Multiply the width and length of the attic floor to obtain the floor area of ​​the attic. Multiply the floor area of ​​the attic by 0.7 to determine how many cubic feet per minute, or cubic feet per minute, of air should drive the fan. Buy a fan that exceeds the total of 15 to 20 percent.
  2. Multiply the p.m. rating of the fan by 144 and then divide the result by 300 to find the attic air intake grid size. Most houses have soffit and singing vents that exceed this amount. If not, then the installation of an air intake duct in the opposite fronton, which is the outer wall part that is located in the attic just below the roof, will increase the efficiency of the fan.
  3. Measure the inside of the fan mounting flange with a tape measure. The mounting flange will surround the fan sleeve, the metal box that the fan resides in, and will be connected to the gable frame. Some fans do not use a manga; they use transverse element bars that are screwed to the gable frame. The air flow direction arrow, stamped on the fan motor or sleeve, will point towards the mounting flange.
  4. Establish a ladder against the house in order to reach the pediment.
  5. Draw a fan opening layout, using measurements on the sleeve or fan rails, on the outside of the gable with a tape measure and a pencil. Installers often use the cardboard box the fan enters as a template. Transfer the opening measurements of the fan to the box and cut the box with scissors. Place the cardboard figure against the pediment and trace the cut with a pencil.
  6. Cut the design lines of the fan opening on the gable with a reciprocating saw. Remove the trimmed section.
  7. Measure the distance between the studs of the gable wall, which is located inside the attic, with a tape measure. Cut a 2-inch by 4-inch wooden board these same measurements with the jigsaw. Toenails, which means to nail at an angle, the wooden boards cut to studs of the gable wall. When completed, the aperture will have framing above and below the aperture.
  8. Measure the distance between the upper and lower frame on the sides of the fan opening. Cut a 2-inch by 4-inch board to these ends. Toe nail of the boards to the upper and lower structure. When completed, the entire opening of the fan will have a wooden board frame.
  9. Nail the pediment of the wooden structure from the outside with 1-inch nails. Drive at least three nails on each side.
  10. Mount the fan following the manufacturer’s instructions. Most screw or nail models through the pre-drilled mounting holes inside the frame from inside the attic. Some models slide into the frame from the outside and join the frame from outside the house through holes inside the fan sleeve. Use a drill and 1-inch screws or 1-inch nails to secure the fan.
  11. Screw fan grille for the pediment from outside the house. The grid will have pre-drilled installation holes. Use the supplied screws or the same 1-inch nails or screws used to hold the fan in place.
  12. Mount the fan controller, basically a thermostat, to a gable support. Follow the manufacturer’s instructions. Usually, the controller is connected to a wall post within 1 foot of the bottom of the fan with screws through the pre-drilled holes, located on each side of the controller.
  13. Open the controller access cover with a flat-head screwdriver or spanner, depending on what the manufacturer is using.
  14. Run a length of 14-2 wire from the fan control box to an attic light. A 14-2 wire has two strings of 14 gauge wire insulation and a bare copper ground wire wrapped in a plastic layer. Use an attic light with a modifier of the traction chain. A light with an electric traction chain switch will have constant supply to it.
  15. Remove 6 inches of the plastic layer from each end of the 14-2 wire with a razor.
  16. Strip half an inch of insulation from each strand at both ends of the cable 14-2.
  17. Push the 14-2 cable into the fan control box through the wire access hole, which is normally located on the side of the control box.
  18. Connect the cables 14-2 to the cables of the control box with cable nuts. Connect the black wires together, the white wires together and the green wire to the copper wire. Close the control box.
  19. Turn on the light of the traction chain on.
  20. Turn on the electricity in the light of the drive chain in the breaker box. When the correct circuit breaker has been turned off, the light of the drive chain will no longer shine.
  21. Open the light chain pull cover. Usually, two flat head screws keep it in place.
  22. Pass the cable 14-2 into the electrical box of the light of the traction chain. Use the same hole as the cable that feeds the light uses of the drive chain.
  23. Connect the 14-2 cable to the light cables of the traction chain with cable nuts. Remove the existing cable nuts, one at a time. Connect the black wires together, the white wires together and the bare copper wires together.
  24. Replace the light cover of the drive chain. Turn on the circuit breaker. The light should shine and the fan will turn on if the attic has a high enough temperature.

Be First to Comment

Leave a Reply

Your email address will not be published. Required fields are marked *