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Homeowner's Best Choice
*See ltd. warranty (available from your
distributor) 



Proper attic ventilation is crucial for a longlasting roofing system! Poor Attic Ventilation Can Ruin Your
Insulation, Proper Attic Ventilation 

Calculating Your Ventilation Requirements

Example: Calculating the number of lineal feet of Cobra® Exhaust Vent needed for a 30’x 40’ attic: 

Step 1
Step 5

Calculate attic square footage 
Intake ventilation MUST be at least equal to exhaust ventilation. To determine the number of intake vents needed, select your vent on page 12, and install enough vents so that their combined NFA is at least 288 square inches. Remember: 
Franzoso
Contracting 914271 4572
Serving
Westchester and Putnam county since 1980