If an attic has a gable (a vertical end wall often pointed at the top), it is usually easy to install a fan there. A gable fan is easier to install than roof-mounted fans or vents, which leak if not sealed correctly.
If your gable does not have a vent, install one. Plastic louvers are less attractive than fixed wooden units, but they seal out wind and rain more effectively.
Calculate the square footage of your attic and total the square footage of your eaves vents. These two figures help you buy a gable fan the correct size.
Gable fans have thermostats to turn on automatically when the attic gets too hot and turn off when it cools.
About 4 hours to run cable inside an attic and install a gable fan (not counting additional framing or cutting for gable vent)
Voltage tester, drill, drywall saw, jigsaw or circular saw, hammer, screwdriver, strippers, long-nose pliers, lineman's pliers
Stripping, splicing, connecting wires to terminals; installing rough wood framing
Find power source and make sure the fan does not overload the circuit. Lay sheets of plywood on the attic floor if the joists are exposed. Wear long clothes, protective goggles, and a dust mask.
Gable fan, cable, wood screws, wire nuts, cable clamps, electrician's tape
Wiring a gable fan is simply a matter of connecting it to power. Because it has a built-in thermostat, wiring for a switch is not needed.