How Many Attic Vents Do I Need

You need 6 66 square feet of attic ventilation.

How many attic vents do i need. The downside of attic ventilation fans. Based on your 1100 sq. Hvi recommends a ratio of 60 to 40 for soffit ventilation to gable or ridge ventilation. If your attic floor has a vapor barrier you will need one square foot of nfa per every 300 square feet of attic floor area half of that will be intake half for exhaust.

In no case should the amount of exhaust ventilation exceed the amount of intake ventilation. The federal housing administration recommends 1 square foot of attic ventilation for every 150 square feet of attic space. Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation for every 300 square feet of attic floor space evenly split between intake and exhaust. This helps make it easy to calculate how many vents you need for your attic once you ve determined your requirements.

To determine the total vent area measure the length and width of your attic in feet then multiply the two measurements to get the attic area then divide the number by 150 to get the vent space in square feet length x width 150. Always have a balanced ventilation system. In order to facilitate this exchange of warm and cool air the general rule of thumb suggests installing at least 1 sq. Attic ventilation fans whether hard wired or powered by their own solar panels seem like a low cost and effective way to help keep your house cool.

Since you want a balanced system you divide by 2 so that half of the ventilation is intake and half is exhaust. They should be divided equally between inlet and outlet vents and they can be used in any combination that will work with your roof s design. Near ridge of the roof. For a home with 2000 square feet of attic floor space you ll first divide 2000 by 300 2000 300 6 66.

And this guideline you ll need a minimum of. Of vent for every 300 sq. Thus if your attic is 450 square feet you need roof vents equaling 3 square feet. 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 general rule is that you must have one square foot of vent space for every 150 square feet of attic area.