Net Free Vent Area, often shortened to NFVA, is the actual open area in a vent that allows air to pass through.
Why It Matters
Vent covers, louvers, screens, and product design all affect how much air can move through a vent. NFVA helps compare ventilation products more accurately.
Common Problems
Common issues include not enough intake, too much exhaust, blocked soffits, undersized vents, and assuming all vents move the same amount of air.
Building Codes & Industry Standards
Attic ventilation should follow applicable building code requirements and ventilation product specifications for net free area.
Exterior Echelon Notes
Exterior Echelon looks at ventilation as a system. NFVA matters because the roof needs both enough vent area and the right balance between intake and exhaust.
