Calculating Attic Ventilation Needs

Enter your square footage.

Calculating attic ventilation needs.

Next multiply the 4 square feet into cubic inches. Nfa is the unobstructed area through which air can pass through a vent usually measured in square inches. Divide the square inches by 2. Of vent for every 300 sq.

Attic square footage 2 square inches of exhaust and square inches of intake net free area nfa needed. Calculate the area of your attic and the proper number of vents. No vapor barrier and for some municipalities in hot climates. Result of item 3 2.

For pitched roofs with vapor barriers. Divide the total vent area by two to. How to calculate attic vent area needed when adding soffit vents. The home ventilating institute hvi recommends that powered attic ventilators provide at least 10 air changes per hour to equalize attic temperature.

Calculate the soffit vent area needed. If your roof is 1200 sq ft soffit floor space you will need 4 sq feet of roof ventilation. Result of item 1 300. Attic ventilation calculator effective attic ventilation requires air to exit at or near the peak of the roof and replacement air to be drawn in under the eaves of the house via soffit venting.

1 square foot of ventilation for every 150 square feet of space. Building codes vary. Divide the square footage item 1 by 300. Measure the length and width of the attic floor space to be ventilated.

Calculate or enter the square footage of the attic or area to be vented. Ventilation manufacturers assign an nfa value to the non motorized vents they make. Change the square feet to square inches. Calculate the square footage of the attic space.

Result of item 2 x 144. Determine the amount of ventilation needed for your home with this formula. In order to find the right calculator divide the attic floor space by 300 sq feet. 1 square foot of ventilation for every 300 square feet of space.

In order to facilitate this exchange of warm and cool air the general rule of thumb suggests installing at least 1 sq. Calculate the total vent area needed. Calculate the square footage of your attic and provide proper attic ventilation with the right number of roof vents ridge vents or soffit vents.