How Many Roof Vents Does A House Need

For example a 6 by 12 inch soffit vent has 72 square inches which when divided by 144 results in a 0 5 square foot opening.

How many roof vents does a house need. You ll need the square footage of your attic to calculate the number of roof vents that you should need. 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. Proper attic ventilation offers numerous advantages to the homeowner. 6 measure the radius of round vents or take half the diameter of the.

Choose one of the following products to meet the recommended exhaust nfva of 528 square inches. Although there are many different types of roof vents to choose from ensuring you have the right number of both intake and exhaust vents is a central part of roof design. Use the calculator below to find out how many exhaust and intake vents you will need on your house. 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.

To calculate the amount of attic exhaust area you will need divide the fan s capacity in cfm by 750. Thus if your attic is 450 square feet you need roof vents equaling 3 square feet. For proper cooling and efficient operation any whole house comfort ventilator requires adequate unobstructed outlets in the attic through soffit vents grilles or louvers. Advantages of proper roofing ventilation.

As a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space. These specialty vents do not affect the. Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation for every 300 square feet of attic floor space evenly split between intake and exhaust.