Attic Ventilation Calculator

Attic Ventilation

Attic Area (sq.ft.)
Ventilation Ratio
Vent Model
NFA / Vent (sq.ft.)
Custom Description
Custom Size

* 1/300 — standard ratio (vapor barrier + balanced ventilation). 1/150 — no vapor barrier.

Attic Area Description Model # Size Approx. NFA Qant. Total Free Calculations
Required NFA Quantity Needed Total NFA Provided Surplus / Deficit