How To Install A Whole House Fan

If you want an alternative to central air, consider installing a whole house fan. A whole house fan circulates hot air outside to the attic, while keeping cool air inside. 

A whole house fan commonly runs on two speeds, which only opens the louvers while the fan is operating. Preventing the warm air from getting back into the house. It is possible to install the fan yourself by following these tips.

Prepare to Work

 For this project, you need:

  • work gloves
  • multimeter
  • tape measure
  • 16d nails
  • hammer
  • staple gun and staples
  • 1 by 4 plywood
  • 2 by 10 plywood
  • spray foam
  • screwdriver
  • caulk
  • hand saw

Find  the square footage of the living area, excluding the garage and the attic, then multiply this figure times three. Choose the cubic feet per minute of the fan based on this number. If your living area is 1500 sq feet, the CFM is 4500.

You also need proper attic space space for venting. To get this number, divide the fan's CFM by 750. In the above example, divide 4500 by 750, which gives six feet of attic space. 

Shut off the main power to the house from the breaker. Try to turn on a switch to very power is off, and run a multimeter over an outlet.

Make the Support

Choose a location for the fan. An ideal place is in the center of the house. In an unobstructed hallway or room. Find the attic joists near the center of this location. 

Press four nails through the joist on each side of the drywall in the desired location. Ensure the shutters have enough space to open. 

Set the template from the fan kit over the location between nails, and staple in place. Trace the shape of the template, and use the saw to cut out the shape that includes a setback of one and a half-inches.

Nail two 2 by 10 pieces of plywood together, setting them in place on the joists, slightly wider than the fan, then secure the block to the joists for the support.

Install the Fan

The instructions should indicate frame measurements. Mark, and trim four pieces of the one by four wood to fit the measurements. 

Set the fan on the support. Attach the frame pieces with hammer and nails. Caulk around the opening, and press the frame in the caulk, adding brackets.

Secure the fan motor to the struts by tightening the bolts with a wrench. Slide the belt in place, adjusting the motor as needed for proper tension, and secure the speed switch in place; following instructions for wiring. Seal the gaps with spray foam.

Restore power, and test the fan. If the fan doesn't work, or if you still you lack ventilation, contact a home air conditioning installation service.