How Much Attic Fan Do I Need

Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split between intake and exhaust for every 300 square feet of attic floor space.

How much attic fan do i need. How an attic fan works. Powered exhaust vents feature an electric or solar powered fan to create an effect similar to that of a turbine view example on amazon. Attic fans are cheap compared to whole house fans. Attic vent fans are commonly rated from 800 to 1 600 cfm making one fans suitable for attics of up to around 2 200 square feet.

According to the home ventilating institute hvi powered attic ventilators need to move a minimum of 700 cubic feet per minute cfm for 1 000 sq. All of that is in place. You need a minimum of 1 square foot of attic air venting for each 750 cfm of air flow. Ft of attic space for example 20 x 50 to be effective.

An attic fan is installed on the slanted side of your roof or on one of the gable sides of your attic. All you need to know about attic ventilation. If you need 6 000 cfm of air flow through your house divide 6 000 by 750 to get a minimum 8 square feet of. Yet i still see the attic temperature reach 145 degrees.

Ideally there should also be plenty of soffit intake space their calculations recommend 336 net square inches of open soffit ventilation to supply 700 cfm. The moving air tries to cool down all the wood attic framing as without the fan the temperature. Attic x 0 7 700 cfm minimum fan rating add an additional 20 cfm x 1 20 if you have a steep roof and 15 cfm x 1 15 for a dark roof. When i last had a new roof installed a few years ago i calculated the soffit intake area i d need for the ridge vent specs.

Professional help labor of 40 then the total would be 125. It might cost you approximately 300 600 for purchase and up to 550 when you include labor. Attic fans exhaust hot air from your attic to the outside. I had my attic floor sealed and a good amount of blown in insulation.

If you want your home air conditioner to cool you better then you might want one or two attic fans. A 1500 square feet attic would cost 70 with additional humidistat costing 15.