How to Install an Attic Fan
There are two main options when installing an attic fan. The first, and easiest option, is to install a fan in front of an existing gable vent to suck out warm air. However, newer homes often do not have gable vents. Instead, an attic fan must be installed by cutting a hole in the roof. If you must cut a hole in your roof, make sure you have an asphalt roof. Any other roofing material will require a professional to cut and seal the hole to prevent leaks.
To install a roof mounted attic fan, begin by cutting a hole using a reciprocating saw in the roof between the roof joists. Make sure to cut it to the size recommended by your attic fan’s manufacturer. Next, you must get on your roof and install the attic fan flange to prevent leaks in your roof. Lift up the layer of asphalt shingles directly above the hole you cut for your attic fan. It is important that you slide the flange underneath these shingles, otherwise leaks will occur.
If you cannot get the flange underneath the lip, you must remove the shingles around the area of the hole, install the flange, and then reshingle the area. For tips on how to do complete the repair look at “How to Replace Damaged Asphalt Roofing Shingles“.
Assuming you can insert the flange underneath the top row of shingles, coat the underneath of the flange with roofing cement. Slide the flange underneath the shingles and push it into place. Nail the corners into place with one roofing nail in each corner. Put a little roofing cement underneath the head of each nail to stop any leaks from occurring. You should also place a small amount of roofing cement over each nail head to protect it.
Screw the attic fan cover to the flange. The attic fan cover should prevent any water from draining off the roof and into your attic. Of course, you should check the attic fan for leaks after the first major rain storm and repair any leaks you see promptly. It is unusual for such leaks to occur, however, if the flange and attic fan cover are installed correctly.
With the cover installed, you can install the attic fan itself. Most attic fans clip into the flange. For an attic fan that is attached in front of a gable vent, it should have clips that allow it to be installed into nearby studs with a few screws.
The final step is to install the regulator. This device turns the fan on and off. Attach the regulator to a nearby stud or joist and screw it into place. You should tap into the nearest electrical power supply wires and join them with the regulator wires. If you are unsure on how to complete this step, call an electrician to do the job for you.
With the regulator installed, set the desired temperature. Most manufacturers recommend setting the attic fan regulator at 95 degrees to get the most energy efficient fan possible.
Installing an attic fan is easily accomplished if you have some experience roofing and know how to use basic hand tools. It is best to call an electrician to connect the regulator if you are not experienced working with electricity in your home, but even with this expense adding an attic fan could save you hundreds of dollars in cooling costs the first summer you have one.
