Department of housing and urban development statutes typically require one sq foot of net free vent area per 150 square feet of attic area to be vented (1/150 rule).
Attic ventilation calculator.
If local code requires the 1/150 rule, please double the requirements.
Attic ventilation calculator the attic ventilation calculator will help you calculate the net free area for your project and the necessary vent width for your ridge vents or vented fascia products.
When a vent line is selected and area entered, select the specific vent diameter to highlight the number of vents of that size which would ventilate the specified area with both 1/300 and 1/150 rule.
The 10 square feet x 144 square inches per square foot =.
Numbers are expressed as linear feet.
Most vent manufacturers supply the nfa for their.
Calculate enter the length and width or the total square footage of the attic floor space to be ventilated.
If you are trying to determine the area in square inches, you can convert it by multiplying 144.
Enter the square footage of the attic or enter the dimensions.
Measure measure the length and width of the attic floor space to be ventilated.
Be sure to factor the amount of soffit overhang into your calculation.
To achieve a balanced system, half that amount is intake and the other half is exhaust, so each should be 3.3 square feet or 475 square inches.
Please enter either the square feet of attic space or the nfa that your project requires and the vented eave and ridge length.
This allows the attic insulation to perform at peak efficiency, helping to maintain constant temperatures in your home.
Attic ventilation calculator how to calculate 1.
To calculate proper intake ventilation for the power vent, divide the cfm capacity of the power fan by a factor of 300 and then convert to square inches.
So for an attic that’s 1,000 square feet, you would divide 1,000 by 150 to calculate that 6.6 square feet nfa of ventilation would be required.
Example attic ventilation calculation required: