Installing a Solar Attic Fan Installing a Solar Attic Fan

What You'll Need
Solar powered attic fan
Tape measure
Drill and 1/4-inch bit
Flat pry bar
Utility knife
Reciprocating saw
Clear silicone caulk and caulk gun

With the advent of the solar attic fan, the ease of installation allows the homeowner to save hundreds of dollars. Solar fans are completely self-contained and require no electrical skills. The typical solar fan will recirculate about 800 cubic feet of air per minute. The fan draws outside air through existing roof vents and can cool the attic by 30 degrees to 40 degrees F. Requiring sunlight to operate, the fan operates most efficiently during the hottest part of the day and will effectively reduce air conditioning costs. Regardless of how well insulated your ceiling may be, the oppressive heat will eventually permeate living quarters.

Step 1 - Mark Location Inside

Placing the solar attic fan near the roof peak on the sunny side of the house, in the middle of the roof is an ideal spot. From inside, mark the center between the rafters at 18 inches from the peak. With a drill and 1/4-inch bit, drill a hole from the attic through to the roof, marking the exact location above. Leave the drill bit in place—detached from drill—to make it easier to locate it on the roof.

Step 2 - Mark Opening

From the roof outside, locate the drill bit from Step 1. Attach a piece of string to the drill bit and cut to the radius of the solar attic fan box. For example, if the diameter of the opening is 12 inches, cut a piece of string to 6 inches. With a piece of chalk, draw a circle using the string as a guide. In essence, you are forming a compass with the drill bit and string.

Step 3 - Cut Opening

First, drill a hole large enough for your reciprocating bade to fit, just inside the drawn chalk line. With the reciprocating saw, cut an opening around the perimeter of the drawn in Step 2. Do not let the "plug" fall into the attic. You can keep the original drill bit in place as a handle.

Step 4 - Prepare Roof Opening

With a utility knife, cut away 2 inches of roofing shingle around the top half of the opening cut for the solar attic fan in Step 3. This arc is required to slide the fan skirt under the shingles. From the center of the hole, you can determine the x and y-axis of the arc.

Step 5 - Finish Roof Opening

Try sliding the solar attic fan box under the shingles cut in Step 4. The fan should slip easily under two or three rows of shingles. Chances are, you will encounter either nails from the shingles or staples from the felt underlayment. With a flat pry bar, remove any nails that interfere. With a slotted screwdriver, remove any staples that prohibit proper placement of the fan.

Step 6 - Set Fan

With the fan sitting directly over the hole cut in Step 3, lift the bottom edge of the skirt. With clear silicone caulk, seal the base perimeter underneath with the caulking gun, from the bottom edge to a few inches under the top as set in Step 5. Using gasket roof screws, attach the base to the roof, passing through the caulked perimeter. To prevent leaks, caulk over the screw heads. Your solar attic fan will start working on its own and begin cooling your attic.

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