ACH Calculator
Enter the floor area of the room.
Set the height of the room’s ceiling in feet (ft).
Input the airflow rate of the air purifier.
Air changes per hour (ACH): 0 ACH
Air Changes Per Hour (ACH) is a measurement used in indoor air quality management to indicate how many times the air within a defined space is changed/moved through the filter media (usually an air purifier's filter).
Formula: ACH = (Airflow in CFM x 60) / (Room Area x Ceiling Height)
| Condition | Required minimum Air Changes per Hour (ACH) |
|---|---|
| Normal conditions | 2 |
| AHAM standard (recommended for many conditions) | 4.8 |
| Smoke or VOCs | 8 |