How to Use a Box Fan in the Attic

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Things You'll Need

  • Utility knife

  • Ruler

  • Wire strippers

  • Phillips screwdriver

  • Wood handsaw

  • Plastic tarp strips

  • Duct tape

  • Caulking gun

  • Caulk

A box fan sucks air from its back and propels it forward. This makes it well suited to substitute for an attic fan, and you can install it yourself. Supplies from a hardware store will be needed, as will some tools that are commonly found in households. No extensive remodeling of the attic must be done, since you will be able to use an existing attic vent.


Step 1

Place the box fan face down on a work surface. Cut off the end of the power cord, using the blade of a utility knife. Slit 3 inches in on the cord's outer insulation from the cut end, using a utility knife. Pull the insulation back from the two wires inside the cord. Strip 1/2 inch of insulation from the ends of both wires, using wire strippers


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Step 2

Turn the fan over. Remove the screws surrounding the grille on the fan, using a Phillips screwdriver. Pull the grille off and place it aside.

Step 3

Place a stepladder beneath a vent grille in the wall of the attic. Remove the screws surrounding the vent's grille, using a Phillips screwdriver. Pull out the screws, using pliers if they have been glued into the grill's frame. Discard the screws.


Step 4

Place the box fan, open side facing away from you, into the opening where the attic grille was. Use a wood handsaw to enlarge the opening if necessary before putting the fan in.

Step 5

Tape strips of plastic tarp, using duct tape, to the sides, top and bottom of the fan to cover the seam between it and the attic wall. Apply caulk from a caulking gun around the fan, where it meets the wall. Let the caulk set for the amount of time specified in the instructions that accompany it. Apply the caulk again.


Step 6

Trip the circuit breaker at the fuse box that supplies electricity to the attic. Find the electrical junction box in the attic. Typically the box is either at the baseboard of a wall or on a beam near the ceiling of the attic.

Step 7

Remove the screws from the cover plate on the electrical junction box, using a Phillips screwdriver. If the box is exposed, ignore this step.


Step 8

Loosen the screw on the box that has a black wire wrapped around it, using the Phillips screwdriver. Loosen the screw on the box that has a white wire wrapped around it in the same manner.

Step 9

Wind the exposed end of the black wire from the box fan a half turn around the screw that has the black wire wound around it. Tighten the screw. Wind the exposed end of the other wire from the fan around the screw that has the white wire wrapped around it in the same fashion. Tighten the screw.

Step 10

Remove the stepladder and restore electric power. Turn the box fan's power switch on to test it.


A ceiling attic vent will require cutting through parts of the wood beams that would otherwise block the box fan from being placed into the opening where the grille was.


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