Attic Ventilation Calculator

Effective attic ventilation requires air to exit at or near the peak of the roof and replacement air to be drawn in under the eaves of the house, via soffit venting. The Home Ventilating Institute (HVI) recommends that powered attic ventilators provide at least 10 air changes per hour to equalize attic temperature.

To estimate the ventilation needs for your attic, please select your roof type and input your attic dimensions:

1. Select your roof type

2. Enter your attic dimensions


Recommended ventilation CFM for your attic : 1,029 CFM

Replacement air is drawn through vents in your soffit. To provide adequate intake air for the CFM recommended above, at least 494 Square Inches of soffit vent area are recommended.


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