How Many Turbine Roof Vents Do I Need

One static vent style is the turbine vent which uses wind to power its enclosed fan all it takes is a light breeze to rotate the blades and suck heat out of the attic view example on the home.

How many turbine roof vents do i need.

Attic must have 5 sq. 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. Roofing resources during covid 19 for contractors for homeowners. Most policies in place require about one foot of vent area for every one hundred fifty feet of attic space.

Having the correct number of turbine vents will provide an effective and balanced system. A single 14 inch diameter turbine vent that is subjected to 15 mph winds can expel up to 1 342 cfm of air. Good attic ventilation is important for preventing ice dams in the winter. As a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space.

A small 12 inch diameter turbine vent with a constant wind speed of 5 miles per hour mph can remove 347 cubic feet of air per minute cfm from the attic space. These can be ridge vents wind turbines or the flat vents your roofer wants to install. Ft of vent space half dedicated for air intake in the soffits and the other half for exhaust on the roof. 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.

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. Also this will give you general guidelines to follow as you complete your project. Rounding up you would need ten 10 750 vents. Thus if your attic is 450 square feet you need roof vents equaling 3 square feet.

Because you always want your intake nfa to meet or exceed the amount of exhaust nfa we will take the amount of exhaust provided and divide by the nfa rating of the deck air. 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. To calculate the number of 750 vents needed divide 480 by 50 to get 9 6 vents. How to determine how many vents you need the rule of thumb used to determine the number of roof vents to install is one for every 300 square feet of attic area if your attic has a vapour barrier and one for every 150 square feet of attic area if the attic does not have a vapour barrier.

If you install a vent that isn t up to code you could end up having to take it down wasting money and time.