Air Changes per Hour (ACH) Calculator
Parameter in HVAC System Design
Air Changes per Hour (ACH) Calculator
ACH: -
Air Changes per Hour or ACH is an important parameter used in HVAC System design.
Formula Used
ACH = Q/V
Where:
- Q = airflow rate (m³/h)
- V = room volume (m³)
Typical ACH Values (Design Reference)
- Residential: 0.5 – 2 ACH
- Office: 2 – 6 ACH
- Laboratory: 6 – 12 ACH
- Hospital (isolation): 12+ ACH
For more advanced ventilation analysis, simple ACH calculations may not fully represent real airflow distribution within a space. In practice, factors such as diffuser layout, recirculation zones, and complex room geometries can lead to uneven air exchange effectiveness. By using tensorHVAC-Pro, you can simulate detailed airflow patterns and ventilation performance within actual 3D environments, allowing you to evaluate not only overall ACH but also how effectively fresh air reaches occupied zones. This enables more accurate design decisions and ensures optimal indoor air quality and occupant comfort.