How Many Turbine Roof Vents Do I Need

As a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space.

How many turbine roof vents do i need.

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. 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. Of vented area for every 300 sq. How many turbine vents you will need depends on a number of factors including the size and type of building.

You will need to have 1 square foot of vent area for every 150 square feet of attic space. Always have a balanced ventilation system. How much air must be moved. Thus if your attic is 450 square feet you need roof vents equaling 3 square feet.

Rounding up you would need ten 10 750 vents. All things being equal wind driven turbine vents also known as a whirlybird roof vent do move more air than flat vents but only when the wind blows. Most policies in place require about one foot of vent area for every one hundred fifty feet of attic space. I d put three or four on a roof to really have a good chance at cooling an attic on a hot summer day.

In no case should the amount of exhaust ventilation exceed the amount of intake ventilation. Near ridge of the roof. If not there should be one vent for every 150 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.

Furthermore this will ensure that a continuous supply of air moves through the desired space. So if your attic is 450 square feet you will need 3 square feet of vent space evened out throughout the entire space and divided equally between inlet and outlet vents. In contrast an active ventilation device might be an electric powered whole house fan or a powered roof ventilator. 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.

If you install a vent that isn t up to code you could end up having to take it down wasting money and time. Passive vents work for free and in almost all instances are silent. Also this will give you general guidelines to follow as you complete your project. To calculate the number of 750 vents needed divide 480 by 50 to get 9 6 vents.

This is one of the most important steps. Based on your 1100 sq.