1346 Recommended Amount of Attic Ventilation - Insulation Energy Efficiency -

Image Text: Cross section > the total vent area is often recommended to be 1/300 of the floor space of the attic > roof vent > roof rafter > air flow > insulation > ceiling joist > soffit vent > wall > 1 square foot of upper vent area required for 600 sq. ft. attic area > Note: the actual vent opening must be larger than 1 sq. ft. because of screen/louver > 1 square foot of lower vent area required for 600 sq. ft. attic area