An exhaust fan in the attic can be a vital addition to your home. Although your house may have vents, they are usually located below the gable, so heat will gather above them. Depending on where you live, the summer temperature in your attic can reach 150 degrees Fahrenheit. By installing an exhaust fan in the attic, you’ll lower that temperature, which will help keep the entire house cooler and more comfortable.
Step 1 - Removing the Vent
Since the exhaust fan draws air in and pushes it across the attic, you will need to install it where one of the vents currently sits. The vent should already be screwed into place. Take out the screws and remove the vent.
Step 2 - Making the Frame
Before you construct the frame, you will need to enlarge the vent opening for the exhaust fan. Center the fan cover on the vent hole and mark around it in pencil. Cut the larger opening with the saber saw, making sure you wear safety glasses. Screw the cover into place, using caulk to make a watertight seal.
Cut two pieces of 2 by 4 wood to fit between the studs above and below the vent cover. Use a level to ensure they’re straight and nail them into place. Next, cut a section plywood to fit onto the two pieces of 2 by 4 wood to create a frame around the vent opening. This will provide a fixing point for your exhaust fan.
Place the fan or the template in the center of the plywood and trace the exhaust fan shape. Cut the shape with the saber saw and screw the plywood to the frame. Screw the fan housing to the plywood and attach to the outer vent housing.
Step 3 - Thermostat
The thermostat is a vital part of the attic exhaust fan. When the attic temperature reaches 95 degrees Fahrenheit, it will cause the fan to automatically switch on, thus cooling the attic. The thermostat will be part of the exhaust fan kit. Screw it in place on the plywood in close proximity to the fan. Connect the wires from the thermostat to the fan following the manufacturer’s instructions, which will come supplied on schematics within the kit.
Step 4 - Wiring
To connect the wiring, you’ll need to turn off the electricity supply to the attic. You will need a powerful flashlight in order to work with the wiring. Turn off the electricity to the attic light at the breaker box. If you prefer, you can turn off the house electricity at the mains as a further safety precaution.
Open the junction box by the attic light. Strip some red, back, and green wiring (red will be live, green is earth, and black is neutral). Unscrew the terminals on the junction box and you will find that the wires for the attic light are already attached. Add the new wires to the correct terminals and screw the terminals back into place.
Run the wire to the thermostat. To keep it secure, staple the wire to every stud using suitably sized cable clips. At the thermostat, you will have two wires. One will be red and the other will be black. The ends of these two wires should be stripped of their insulation covering.
Next, strip the ends of the wires you’ve run from the junction box. Use wire nuts to connect the red wire to the red wire, and black to black. The green wire will attach to the grounding screw inside the thermometer. Turn the electricity back on and your attic exhaust fan is now ready to run.