Air Changes Calculator
Calculate air changes per hour (ACH) for a room based on airflow and room volume.
How to Use the Air Changes Calculator
- Enter the ventilation airflow in CFM.
- Enter the room volume in cubic feet.
- Click Calculate for ACH and code compliance result.
使用场景
- •Residential ventilation system design.
- •Commercial building IAQ assessment.
- •HVAC commissioning checks.
- •Building code compliance verification.
公式
ACH = (Airflow CFM × 60) / Room volume (ft³). Minimum residential: 0.35 ACH.
常见问题
What is ACH?
Air Changes per Hour — how many times the entire air volume in a room is replaced each hour.
What ACH is required by code?
ASHRAE 62.2 requires a minimum of 0.35 ACH for residential spaces.
What is a typical ACH for different spaces?
Bedroom: 1–6. Office: 4–10. Hospital OR: 20–25. Cleanroom: 100+.