Sizing Attic Ventilation Fans

Attic fan size chart for quick reference.

Sizing attic ventilation fans.

Example 20 wide by 50 long attic. See the benefits of attic ventilation a new roof is more than just shingles. 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. This attic ventilation calculator computes the size and number of solar powered attic fans to achieve the proper ventilation for your attic.

Well managed indoor air quality is crucial to code compliance. Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge. How to size a whole house attic fan. A whole house attic fan is installed in the ceiling between the top floor and the attic as a supplement to air conditioning.

Our installer friendly energy star ventilation solutions help you design beyond code without compromising interior aesthetics. A whole house fan sucks warm house. Next multiply the square feet of attic space by 0 7 to get the minimum number of cubic feet of air per minute that the fan should be rated to move. Intake air vent size.

If your attic requires a 1500 cfm fan then it should also have a 1500 300 5 sq ft air vent. They are typically easier to install and won t detract from the appearance of your roof. Minimum intake air vent size cfm 300 sq ft. So here the cfm of the fan cfm x 1 15.

For the exhaust to work properly the attic should have enough intake air vents. Effective attic ventilation systems reduce damaging heat and moisture in your attic promote energy efficiency by helping to reduce the load on your air conditioner in the summer and also reduce the risk of ice dam formation on your roof. The result is a cooler attic space with plenty of air exchange. 20 x 50 1 000 sq.