Residential Building Envelope Science
Solar Attic Fan & Net Free Vent Area (NFVA) Sizer
Calculate attic ventilation requirements per IRC Section R806 (1/150 vs 1/300 ventilation rule), solar attic fan airflow capacity (CFM), and soffit intake vent balance.
Attic Footprint & Roof Geometry
Ventilation Takeoff & Solar Fan Sizing
Solar Attic Fan Airflow Rating (CFM)
Sized at 0.7 CFM per sq ft + pitch/dark factor
Net Free Vent Area (NFVA) Required
IRC 1/150 rule (total intake + exhaust)
Recommended Solar Fan Setup
Brushless DC solar-powered unit
Always verify adequate intake ventilation (soffit vents). Without equal intake area, an attic fan creates negative pressure that can pull conditioned AC air out of the home.