Net Free Ventilation Area Calculator

Understanding Attic Ventilation

Proper attic ventilation is crucial for maintaining building integrity and energy efficiency.

  • Moisture Control Prevents condensation and mold growth.
  • Temperature Regulation Reduces cooling costs and prevents ice dams.
  • Building Protection Extends roof life and protects materials.
  • Energy Efficiency Improves overall building performance.

Code Requirements

Basic Ratio

1:150 without vapor barrier

With Barrier

1:300 with vapor barrier

Distribution

50/50 high/low vents

Minimum

Net free area calculation

Ventilation Types

  • Soffit Vents Low intake ventilation.
  • Ridge Vents Continuous exhaust at peak.
  • Gable Vents End wall ventilation.
  • Roof Vents Spot ventilation options.

Installation Best Practices

  • Proper Balance Match intake and exhaust.
  • Clear Path Maintain airflow path.
  • Insulation Don't block soffit vents.
  • Maintenance Regular inspection needed.