- Ideas & How-Tos
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Exhaust heat and humidity from your home's attic, even on calm days with no wind, simply by installing a gable-mounted power vent.
Use this checklist when you go to the store and purchase your items.
Power ventilators for gable-mounted vents come in a number of sizes and are rated by cubic feet of air moved per minute (CFM).
Example: An attic with 1,500 square feet x .7 = 1,050 CFM
Make sure you also have adequate air intake. A rule of thumb: 1 square foot of intake for every 300 CFM of ventilator.
Example: 1,170 CFM ventilator / 300 = 3.9 square feet of intake ventilation
This is the minimum intake required.
Make sure all factory-installed bolts are securely tightened. There are many louver styles available. These instructions will apply to all types of gable louvers commonly used. These instructions assume a rectangular louver with a stationary vane.
Measure the dimensions of the existing louvers from inside the attic.
Cut a piece of plywood the right size to seal off this area. You want to block all airflow except for the vent you'll be installing.
Place the fan on the board in the center and trace around it.
Cut out the area for the fan using a jigsaw or coping saw.
Attach the fan over the hole on the board, and secure the brackets with screws.
Mount this entire assembly over the existing louvers.
Attach the thermostat close to the airflow drawn by the fan or let it hang free.
Set the thermostat at 90ºF degrees. The power ventilator will automatically start at approximately 102ºF degrees. When the temperature drops to 90ºF degrees, the fan will automatically shut off. You can test this with a work light or hair dryer.