Attic Fan Intake Air

Similar to the static method adequate amounts of intake air into the attic space should be provided.

Attic fan intake air.

That path is supposed to be from low in the attic intake vents to the highest possible exit point in the attic exhaust vents. A minimum of 70 linear feet or 700 sq in. 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. Not having enough intake air could lead to negative pressure.

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. 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. See figure 2. Intake vents located at the lowest part of the roof under the eaves allow cool air to enter the attic.

Hot air exhaust vents located at the peak of the roof allow hot air to escape.