How Much Attic Ventilation

Generally speaking you need a ratio of 1 300 where for every 300 square feet of ceiling space you need 1 square foot of attic ventilation.

How much attic ventilation.

You can also contact your local municipality to check on building code in your area. Of vent for every 300 sq. We show you how to install soffit vents step by step to improve your attic ventilation. Soffit vents help increase the airflow are easy to install and only cost about 3 per 8 ft.

Always have a balanced ventilation system. Attic ventilation keeps the air moving and stops mold from growing but too much ventilation can be just as bad as having none. The following product options will allow you to achieve an intake nfva of 528 square inches. Choose one of the following products to meet the recommended intake nfva of 528 square inches.

Here s how to install soffit vents step by step to improve the airflow in your attic. However if your attic has blocked soffit vents and is not well sealed from the rest of the house attic fans will suck cool conditioned air up out of the house and into the attic. 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. The basic formula for a typical residence is 1 foot of passive vent opening per every 150 square feet of attic size.

According to the national roofing contractors association nrca a power vent with an airflow rate of 1 0 cubic foot per minute per square foot of attic space measured at the attic floor is generally considered to be equivalent to a 1 150 ventilation ratio. Ventsure inflow intake vent. How much attic ventilation is enough. Attic fan ventilation attic fans are intended to cool hot attics by drawing in cooler outside air from attic vents soffit and gable and pushing hot air to the outside.

That said air resistance and interference such as vent grates reduces the area of true ventilation. Ideally the total vent space should be equally divided between lower soffit vents and upper vents at the roof peak. To keep air flowing your roof needs just the right amount of attic ventilation. Allows cool dry air to enter the attic.

In order to facilitate this exchange of warm and cool air the general rule of thumb suggests installing at least 1 sq. In no case should the amount of exhaust ventilation exceed the amount of intake ventilation. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca.