How much attic ventilation does Air Vent recommend for a typical attic? How do I calculate proper attic ventilation?
A. Research has shown that the best way to ventilate an attic is with a system that provides continuous airflow along the entire underside of the roof sheathing. Achieving this desired airflow requires a balanced system of intake ventilation low at the roof’s edge or in the soffit/eaves and exhaust ventilation at the ridge. For optimum attic ventilation for today’s tighter built, tighter remodeled homes that have more efficient building materials, Air Vent recommends exceeding minimum building codes. Air Vent recommends 1 square foot of ventilation for every 150 square feet of attic floor space with half the ventilation represented by intake vents and half by exhaust vents such as ridge vents. For minimum building code requirements use the 1/300 ratio instead of the 1/150 ratio.
