Proper Attic Ventilation

Today’s homes are built tightly, which helps make them more energy-efficient. However, without an appropriately designed, installed, and maintained ventilation system, they can suffer a multitude of negative consequences.

In order to meet building requirements, according to the International Building Code: a specific amount of NFA* must be provided.

• 1 sq.ft. NFA per 300 sq.ft. of attic space
• Must be balanced, high and low
• Requirement changes to 1 sq.ft. NFA per 150 sq.ft. without a vapor retarder

*Net Free Area = The total amount of unobstructed area through which air can pass through a vent. Not to be confused with airflow.

Building codes are based on NFA, but NFA does not indicate AIRFLOW performance. Vents with identical NFA perform differently. Tamlyn's continuous vents move more air than siding vents, even if NFA is identical. Siding manufacturers sell “ventilated soffit.�? This does not mean it is a vent !