Before You Begin
Attics can quickly heat up to 150 degrees in the summer heat. Without proper ventilation the heat can cause damage to your roof. Installing an attic fan can alleviate the heat and give your attic a breath of fresh air. It can also increase the savings on your cooling bill.
Gable fans are not hard to install, but there are a few things to consider before you begin. First, check the vents that are currently in the attic. There should be equal vents in the soffit to vents located higher up the roof such as ridge vents. The vents should also be checked to make sure they are not clogged by any debris. Because there are many types of attic fans, you will want to choose the one that is best for you. A thermostat-controlled gable attic fan with an automatic shutter will work great in most cases. This type of fan only comes on when needed and the shutter only opens when the fan is in use, thus keeping out the cold air of the winter and not allowing driving rain to come though the fan during a storm.
Installing the Shutter
The shutter will take the place of an existing gable vent. If the vent is smaller than the shutter the hole will have to be made larger for the shutter. This can be accomplished by removing the vent and tracing the outside of the shutter on the outside of the house. Measure 5/8-inch in from the trace mark and cut out the new opening with a sabre saw. The siding, if it's not flat, will have to be cut away to allow the shutter flange to lay flat over the opening. The shutter can then be screwed over the opening and any blocking you removed to install the shutter can be nailed back on.
Installing the Fan
The fans are mounted to a piece of plywood before they are installed in the gable. The fans normally come with a template to use to trace the outline of the fan onto the plywood. The circle should be centered on the plywood and then is cut out with a sabre saw. The fan is then centered over the hole and the mounting bracket is screwed into the plywood. The entire assembly can then be nailed to the gable framing with the fan centered over the shutter.
To install the electric you will need to check on your local building codes. You may be able to use an attic circuit that has enough reserve capacity to handle the fan. If not, a new 15 amp circuit will need to be installed into your breaker box. This will need to be inspected by an electrical inspector for you local code office. If you do not know how to install electric, this is not an area where you should try to do it yourself. Installed wrong can have serious consequences. Hire an electrician to do the job for you. The extra cost will soon be absorbed by the savings on your electric bill and roof repairs.