Attic Fan Intake Air

Not having enough intake air could lead to negative pressure.

Attic fan intake air.

Similar to the static method adequate amounts of intake air into the attic space should be provided. Hot air exhaust vents located at the peak of the roof allow hot air to escape. 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. A minimum of 70 linear feet or 700 sq in.

Intake vents located at the lowest part of the roof under the eaves allow cool air to enter the attic. See figure 2. Since attic breeze solar powered fans are variable speed in terms of airflow the calculation for required air intake ventilation must be made at the fan s highest rating to ensure adequate ventilation under the full range of operation. 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.

If two different types of exhaust vents are combined for example a ridge vent and a gable louver the primary path of air becomes the distance between the two types of exhaust vents.