Sizing Attic Ventilation Fans

See the benefits of attic ventilation a new roof is more than just shingles.

Sizing attic ventilation fans.

A whole house attic fan is installed in the ceiling between the top floor and the attic as a supplement to air conditioning. How to size a whole house attic fan. They can quickly remove a larger volume of hot and or humid air from your attic compared to static ventilation which helps save money on your heating and cooling. So here the cfm of the fan cfm x 1 15.

A whole house fan sucks warm house. 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. Example 20 wide by 50 long attic. 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.

20 x 50 1 000 sq. Master flow egv5 gable mount attic ventilators are master flow egv5 gable mount attic ventilators are a great choice for exhaust ventilation. This attic ventilation calculator computes the size and number of solar powered attic fans to achieve the proper ventilation for your attic. Minimum intake air vent size cfm 300 sq ft.

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. Intake air vent size. 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.

Attic fan size chart for quick reference. Well managed indoor air quality is crucial to code compliance. The result is a cooler attic space with plenty of air exchange. They are typically easier to install and won t detract from the appearance of your roof.