O’Hagin Vent Calculator

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Questions? Call us at (877) 324-0444
Step 1: DETERMINE SQUARE FEET OF CODE-REQUIRED VENTILATION
÷ Compliance Method
Step 2: CONVERT SQUARE FEET OF CODE-REQUIRED VENTILATION TO SQUARE INCHES
x 144 = Total Square inches of Code-Required Ventilation
Step 3: DETERMINE THE ADEQUATE NUMBER OF O’HAGIN VENTS REQUIRED
Total O’Hagin Vents Required for sq. inches:
O’Hagin Tapered Low-Profile
72.0 sq. in NFVA

Vents High:
Vents Low:
O’Hagin High-Profile Model S
97.5 sq. in NFVA

Vents High:
Vents Low:
O’Hagin Low/Medium Profile Model M
86.25 sq. in NFVA

Vents High:
Vents Low:
O’Hagin Low-Profile Model Flat
98.75 sq. in NFVA

Vents High:
Vents Low:
MANUFACTURER’S RECOMMENDATIONS
The patented O’Hagin Balanced Ventilation System utilizes O’Hagin vents placed strategically within the field of roofing material both high (near the ridge for exhaust) and low (near the eave for intake). This strategic high and low placement of O’Hagin vents allows the balanced system to fully optimize both wind and thermal effects to provide superior passive ventilation throughout the attic. Additionally, placement of O’Hagin vents both high and low should provide an equal, balanced rate of ventilation performance in each area. The calculations above do not include any potential Net Free Ventilation Area (NFVA) values provided by alternative ventilation methods that may be present in any specific structural design.
Code Required Attic Ventilation Calculations
÷ = x 144 = Total Square inches of Code-Required Ventilation
6″ Extended Flange 72.00 sq. in NFVA |
4″ Standard Flange 72.00 sq. in NFVA |
Tapered, Low-Profile Vents For: Slate, Shake and Shingle Roofs
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Exhaust/High Vents: Intake/Low Vents: Total Square Inches Provided: |
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Profile Specific Attic Vents For: Clay and Concrete Tile Roofs
Low-ProfileFlat | High-Profile‘S’ | Medium-Profile‘M’ |
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98.75 sq. in NFVA | 97.50 sq. in NFVA | 86.25 sq. in NFVA | 86.25 sq. in NFVA |
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Exhaust/High Vents: Intake/Low Vents: |
Exhaust/High Vents: Intake/Low Vents: |
Exhaust/High Vents: Intake/Low Vents: |
Exhaust/High Vents: Intake/Low Vents: |
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Total Square Inches Provided: | Total Square Inches Provided: | Total Square Inches Provided: |
MANUFACTURER’S RECOMMENDATIONS
The patented O’Hagin Balanced Ventilation System utilizes O’Hagin vents placed strategically with in the field of roofing material both high (near the ridge for exhaust) and low (near the eave for in take).This strategic high and low placement of O’Hagin vents allows the balanced system to fully optimize both wind and thermal effects to provide superior passive ventilation throughout the attic. Additionally, placement of O’Hagin vents both high and low should provide an equal, balanced rate of ventilation performance in each area. The calculations above do not include any potential Net Free Ventilation Area (NFVA) values provided by alternative ventilation methods that may be present in any specific structural design.
Visit us on line at Ohagin.com for more info. or call us at: (877)324-0444