How to Install A Gable & Attic Exhaust Fan
Attic exhaust fans are available in two types: gable-end and roof-mounted. A gable-end fan is installed inside the attic, with a louvered opening to the outside. A roof-mounted attic fan is positioned near the top of the roof, under an aluminum mushroom cap that protects the fan from the elements. Adjustable thermostats on the fans control both kinds. The temperature in the attic causes the thermostat to turn the fan on and off to remove hot air from the attic. Does this Spark an idea?
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Things You'll Need
- Gable-end or roof-mounted attic exhaust assembly
- Measuring tape
- Circuit breaker
- Electrical wiring
- Support clamps
- Wire nuts
- Electrical tape
- Power saw
- Reciprocating saw
- Roofing nails
- Roofing tar
- Decorative louver vent
Instructions
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Roof-Mounted Exhaust Fan
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1
Select a roof-mounted exhaust fan recommended for the cubic footage of the attic. The fan should be adequate to efficiently pull out hot air. It may be necessary to install two or three roof-mounted exhaust fans. Two fans running intermittently is more energy efficient than one fan running nonstop.
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2
Determine where on the roof the fan will be installed. Hot air rises to the peak of the attic ceiling. The higher on the roof and the closer to the ridge, the better.
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3
Verify that the manufacturer's specifications for the circuit breaker size are met; a 20-amp breaker and No. 12 wire is standard. Run power from the home's electric service panel to the location where the roof-mounted exhaust fan will be installed. The fan installation will include a hot wire, a ground wire and a neutral wire, connected to the service panel and circuit breaker and to the fan.
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4
Using a reciprocating saw or a power saw, cut a vent hole in the roof where the exhaust fan will be located. A hole measuring 12 inches square is standard.
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5
Nail the mushroom cap with roofing nails, tucking the cap under the head shingles. Follow any diagram accompanying the exhaust fan assembly for flashing specifications. Apply roofing tar to seal the mushroom cap valance.
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6
Mount the exhaust fan assembly, working from inside the attic, using the brackets and screws provided by the manufacturer.
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7
Turn off the electricity to the exhaust fan at the circuit breaker. Wire electrical connections to the thermostat; twist the wires to connect neutral to neutral, hot to hot and ground to ground wires. Screw on wire nuts and wrap with electric tape. Do not allow the electric feed to hang; apply supports following local building codes.
Gable Exhaust Fan
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8
On one vertical side of the attic, saw a hole and install a decorative louver cover, if there is not an existing louver vent.
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9
Working inside the attic at the louver, follow the manufacturer's specifications for mounting the exhaust fan motor, fan blade and thermostat control. Secure with the brackets and screws included with the assembly.
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10
Turn off electricity at the circuit breaker. Wire the connections to the thermostat by twisting the wires together: neutral to neutral, hot to hot and ground to ground. Support all electrical lines to the attic wall and ceilings using clips or other hardware in compliance with local building codes.
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Tips & Warnings
The thermostat will turn the exhaust fan on and off, depending on temperature in the attic. It is not necessary to manually turn off the exhaust fan during the winter.
Never use extension cords in an attic exhaust fan installation. Always turn electric power off at the circuit breaker when undertaking a wiring project.
