Step 1

Determine the length and width of the space you desire to ventilate.

Be sure to factor the amount of soffit overhang into your calculation.

Step 2

Choose a roof ventilation product. Determine the products square inches of net free area and enter it in the below box.

or select a product Select a productSHEDLIGHT ROOF VENT 50 SQ. IN. TRANSLUCENTSHEDLIGHT ROOF VENT 75 SQ. IN. TRANSLUCENTSQUARE TOP ROOF VENT 50 SQ. IN. BLACKSQUARE TOP ROOF VENT 50 SQ. IN. BROWNSQUARE TOP ROOF VENT 50 SQ. IN. GRAYTALL ROOF VENT 50 SQ. IN.BLACKTALL ROOF VENT 50 SQ. IN.BROWNTALL ROOF VENT 50 SQ. IN.GRAYTALL ROOF VENT 50 SQ. IN.WWSQUARE TOP ROOF VENT 50 SQ. IN. WWSLANTBACK ROOF VENT 61 SQ. IN. BLACKSLANTBACK ROOF VENT 61 SQ. IN. BROWNSLANTBACK ROOF VENT 61 SQ. IN. GRAYSLANTBACK ROOF VENT 61 SQ. IN. WWSQUARE TOP ROOF VENT 75 SQ. IN. BLACKSQUARE TOP ROOF VENT 75 SQ. IN. BROWNSQUARE TOP ROOF VENT 75 SQ. IN. GRAYSQUARE TOP ROOF VENT 75 SQ. IN. WWBREEZELINE SQUARE TOP ROOF VENT 50 SQ. IN.BREEZELINE SQUARE TOP ROOF VENT 50 SQ. IN.BREEZELINE SQUARE TOP ROOF VENT 50 SQ. IN. WWWEATHERPRO TURBO 117 SQ. IN. BLACKWEATHERPRO TURBO 117 SQ. IN. BROWNWEATHERPRO TURBO 117 SQ. IN. GRAYWEATHERPRO TURBO 117 SQ. IN. WWWEATHERPRO VENTILATOR 48 SQ. IN. BLACKWEATHERPRO VENTILATOR 48 SQ. IN. BROWNWEATHERPRO VENTILATOR 48 SQ. IN. GRAYWEATHERPRO VENTILATOR 48 SQ. IN. WWWEATHERPRO VENTILATOR 95 SQ. IN. BLACKWEATHERPRO VENTILATOR 95 SQ. IN. BROWNWEATHERPRO VENTILATOR 95 SQ. IN. GRAYWEATHERPRO VENTILATOR 95 SQ. IN. WWWEATHERPRO VENTILATOR 130SQ. IN. BLACKWEATHERPRO VENTILATOR 130SQ. IN. BROWNWEATHERPRO VENTILATOR 130SQ. IN. GRAYWEATHERPRO VENTILATOR 130SQ. IN. WWWEATHERPRO PRO50 ROOF VENT 50 SQ. IN. BLACKWEATHERPRO PRO50 ROOF VENT 50 SQ. IN. BROWNWEATHERPRO PRO50 ROOF VENT 50 SQ. IN. GRAYWEATHERPRO SLANTBACK ROOFVENT 50 SQ. IN. BLACKWEATHERPRO SLANTBACK ROOFVENT 50 SQ. IN. BROWNWEATHERPRO SLANTBACK ROOFVENT 50 SQ. IN. GRAYWEATHERPRO SLANTBACK ROOFVENT 50 SQ. IN. WWWEATHERPRO PRO50 ROOF VENT 50 SQ. IN. WHWEATHERPRO PRO50 ROOF VENT 50 SQ. IN. WWWEATHERPRO PRO75 ROOF VENT 75 SQ. IN. BLACKWEATHERPRO PRO75 ROOF VENT 75 SQ. IN. BROWNWEATHERPRO PRO75 ROOF VENT 75 SQ. IN. GRAYWEATHERPRO ROOF VENT 75 SQ IN WHITEWEATHERPRO PRO75 ROOF VENT 75 SQ. IN. WW12″ X 12″ SQUARE GABLE VENT WH18″ X 18″ SQUARE GABLE VENT WH18″ ROUND GABLE VENT WH22″ ROUND GABLE VENT WH18″ OCTAGON GABLE VENT WH22″ OCTAGON GABLE VENT WH12″ X 18″ SMALL RECT. GABLE VENT WH18″ X 24″ LARGE RECT. GABLE VENT WH18″ HALF MOON GABLE VENT WH22″ HALF MOON GABLE VENT WH22″ CATHEDRAL GABLE VENT WH22″ X 28″ LARGE RECT. GABLE VENT WHPLASTIC RIDGE ROLL BLACKPLASTIC RIDGE ROLL BLACK WITH FILTERWEATHERPRO RIDGE VENT METRIC BLACKWEATHERPRO RIDGE VENT METRIC BROWNWEATHERPRO RIDGE VENT METRIC WWWEATHERPRO RIDGE VENT IMPERIAL BLACKWEATHERPRO RIDGE VENT IMPERIAL BROWNWEATHERPRO RIDGE VENT IMPERIAL WWWEATHERPRO SOLID RIDGE VENT 12″ BLACKRIDGE ROLL 20’L X 8″W BLACK FILTERRIDGE ROLL 20’L X 11.5″W BLACK FILTERRIDGE ROLL 20’L X 10.5″W BLACK FILTER

Step 3

Based on your calculations, and product choice, you require the below

number of ventilation units for your project:

Now you can select the appropriate Duraflo ventilators by referring to the NET SQUARE INCHES ratings for different models within our catalogue.

For proper ventilation balance:

• 50% of your total NET FREE AREA should be vented from the soffit area and
• 50% should be vented from the roof area.

Example:

The horizontal roof area of your home (including overhang) is 36 feet by 28 feet. In this example the Duraflo NFA Calculator will provide your NET FREE AREA as 483.

You require 483 square inches of ventilation, ideally:

• 241.5 square inches spread out in the soffit areas and
• 241.5 square inches located in the roof area.

Note: In this example, rounding off your “roof area” requirements to 250 sq. in. you would need 5 duraflo 6050-50 sq. in. roof vents.