How to Size an Attic Fan
An attic fan is an alternative method to cool your home when the air outside is cooler than the air in your home, such as during the night. When the attic fan is turned on, the warmer air is cycled out of the home and is replaced by cooler air from outside. The size of your attic fan depends on the size of the home or rooms that it is intended to cool. For example, in some homes an attic fan cools the whole house while other homes use a combination of attic fans and window fans for cooling. Does this Spark an idea?
Instructions
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Determine which rooms will be cooled by the attic fan. This can be the entire house or only a few rooms.
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Measure the cubic footage of the rooms that you want the attic fan to cool and then take the total by adding them together. You can find the number of cubic feet of each room by multiplying the length times the width times the height. For example, a room that is 13 feet long, 10 feet wide and 8 feet high would be 1,040 cubic feet.
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Select a fan with an exhaust rating of at least as many cubic feet per minute as the fan will be responsible for cooling. For example, if your home is 8,000 cubic feet and you want your attack fan to cool all of it, your attic fan should have a rating of at least 8,000 cubic feet per minute (CFM).
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Tips & Warnings
Install the attic fan above a hallway so the fan can cycle air out of all rooms equally.
If your home is in a mild climate you may not need as large an attic fan as you would in a hot and humid climate.
