How to Install a Whole-House Fan

When the air inside your house is too warm but the outside air is comfortable, you can use a whole-house fan to bring some of that cooler air into your living space. The fan is installed in the ceiling just below your attic, and it’s hidden by louvers so that it won’t look out of place. Here’s how to install one yourself:

Whole-house fans are typically controlled by thermostats, wall switches or pull cords. They can usually be wired to work in conjunction with a power ventilator on the roof.

Before you set out to buy your fan, make sure you know the square footage of your home. This will help you determine the correct fan to use.

Here’s how to install a whole-house fan:

Materials and Tools:

whole-house fan
drill, with drill bits and driver bits
wrenches
hammer
framing nails
2-by-4-inch studs
drywall saw
handsaw
measuring tape
framing square
wire stripper
wire nuts
safety glasses
work gloves
long-sleeve shirt
dust mask

Steps:

1. Remove the blades from the whole-house fan before you begin installing it. This reduces the weight and makes the fan less cumbersome.

2. On the uppermost ceiling in the living area of your home, locate a central point where the ceiling is directly below the attic. Measure the area to be sure your fan will fit.

3. From the attic, go to the general location where you plan to install the fan. Make sure the area is free of obstructions such as ductwork and plumbing. Move the insulation, electrical wiring, and other obstacles away from the area. (Be sure to wear long sleeves, work gloves, and a dust mask if you'll be working with fiberglass insulation.)

4. Measure the installation space from inside the attic. If your fan will span two ceiling joists, make reference marks on either side of the center joist and drill holes through the ceiling so you can make your final cuts from below.

5. From the floor below, use the hole(s) you just drilled as a reference to measure and mark cutting lines on the ceiling. The lines should be based on the inside dimensions of the louver flange. Double-check the lines to make sure they’re square, and cut them with a drywall saw or a reciprocating saw. Be careful not to damage the rest of the ceiling. You may need an assistant to help you hold the ceiling material in place so that it doesn’t fall prematurely.

6. Remove fasteners such as drywall nails or screws from any exposed joists.

7. Create a frame to support the fan using 2-by-4-inch blocking between the joists around the cut area of the ceiling. This will serve the dual purpose of supporting the weight of the fan and providing support for the ceiling material.

8. Install brackets in the pre-drilled holes in the frame of your fan. Fasten the brackets tightly.

9. Set the fan in place and mark the bracket holes. Remove the fan and drill pilot holes. Then set the fan back in place and secure it with bolts.

10. When the fan is secure, reattach the fan blades. Spin the fan to make sure the blades turn freely.

11. Make the electrical connections for the fan based on the manufacturer's instructions. You may wish to hire a licensed electrician to make these connections.

12. Secure the louver to the ceiling.