Every home needs a good ventilation system. To make sure, no air is trapped and no excessive moisture is built, we can install turbine vents on our roof.

A turbine vent is a must for your roof. You may ask yourself, how many roof turbines do I need? Well, allow us to give you the answer.

Keep reading the article to know more.  

What Is Turbine Vents

Turbine vents are wind-powered. It rotates and sucks out hot air from inside the house to the outside. It helps to keep a cool temperature inside your house. Free and pure airflow inside your house will extend and strengthen your roof’s lifespan.

How Many Roof Turbines Do I Need

Depending on whether you have a vapor barrier in your attic or not, how many roof turbines you need can change. Here are steps you can take to find out the number of turbine vents you will need.

If you have a vapor barrier, there should be at least one vent per 300 square feet of space. And if you don’t have one, one vent per 150 square feet of space.

For example, a vent space of 4 square feet is needed for an attic area of 600 square feet. Note that roofs that have more slop than 6:12 have more volume. So, you should add even more turbine vents.

These 4 square feet of vent space required is known as NFA as in Net Free Area. They should be split up equally as exhaust and intake vents. In this example that would amount to 2 square feet of vent space.

Next, convert the square feet to square inches by multiplying it with 144. Here, 2*144=288 square inches for the inlet and another 288 square inches for the outlet.

Now, you have to divide this NFA (288 square inches) by the vent’s NFA ratings.

As an example, the Deck-Air DA-4 has an NFA rating of 36 square inches. If we divide 288 by 36, we get 8. That means the number of roof turbines we will need is 8.

So, we need 8 roof turbines as an outlet vent.

Roof Vents Installation

Even if you find out how many roof turbines you need, we recommend, you rather call a professional roofer to install the turbine vents.


So, by following our detailed guidelines, we hope that you were able to find out the answer to how many roof turbines do I need?

Please stay with us for more informative articles. Thank you.


As a civil engineer and roofer, I love to share the experience that I have gained through the last couple of years. In the roofing industry, practical experience is a very crucial fact that can help you a lot. Hence, I want to help you with my blog.

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