Air Changes per Hour Calculator

Inputs

View results
Served room or zone floor area.
m²
Average clear height used to calculate room volume.
m
Target air changes per hour for the room or process.
ACH
Airflow supplied to, exhausted from or recirculated through the room.
m³/h

Results

Default result
Edit inputs
Required airflow (Q_req)
324 m³/h
Pass

airflow for 6.00 ACH

Also computed

Actual air changes (ACH) Pass 6.667 ACH

meets or exceeds the target air-change rate

Room volume (V) 54 m³

Minutes per change (t) 0.15 min

Method notes 3 notes
  • Room volume is floor area times average ceiling height.
  • ACH = airflow × 3600 / room volume. Required airflow = room volume × target ACH / 3600.
  • ACH is a room air-change screen, not a complete outdoor-air code calculation. For occupied-building ventilation, check the applicable ASHRAE 62.1/62.2 or local-code method.

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