Calculating Attic Ventilation Needs

Length x width of attic in feet 150 total sq.

Calculating attic ventilation needs.

The federal housing administration recommends 1 square foot of attic ventilation for every 150 square feet of attic space. Multiply the length of the attic times the width in feet to find the attic area then divide by 150 to find the total square feet of vent space needed. Standard attic vents like af 50 s ventilation fans or solar powered attic fans. Calculate the total vent area needed.

Ft divided by 150 equals 10 sq. Most attic ventilation manufacturers list the longer formula on their websites and inside key product brochures. For balanced ventilation an equal amount of intake vent area net free area should also be installed. Calculating attic ventilation requirements.

Let s use the following simple ranch house for an example. Let owens corning roofing help you calculate exactly how much ventilation you will need for a healthy and balanced attic with our 4 step ventilation calculator. But the shortcut is just as good and faster. Calculate or enter the square footage of the attic or area to be vented.

Divide the square footage item 1 by 300. Here are the answers to the five most frequent questions pertaining to calculating attic ventilation. Use avp s roof vent calculator to determine the number and size of exhaust vents you will need. Of total vent space needed.

Calculate the square footage of the attic space. Use our easy 3 step attic ventilation calculator to determine your attic square footage and ventilation needs. The two square feet is divided equally between the intake and the exhaust one square foot for each. Calculating ventilation area of attic kitchen ventilation text.

Calculation q a. Ok to determine how much ventilation area you need for your house all you need to know is the square foot area of the attic to be ventilated. The house measures 30 feet by 50 feet. Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge.

Hence you would need two square feet 600 300 of attic ventilation. A 50 x 30 attic would have a total area of 1 500 sq. If you are in the puget sound area of washington state and would like to have a free attic ventilation evaluation or roof estimate please contact us at 253 445 8950 or fill out our quick estimate form. Divide the attic s square footage by 150.

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.