Ventilation Calculator

Calculate required ventilation rate from CO₂ criteria, room area, and statutory air change rates — free building services tool

Related Categories:Building Services

Calculation Method

Room Dimensions

Width (m)

Depth (m)

Height (m)

Room Volume: 54.0 m³ | Floor Area: 20.0 m²

Room Volume Method

Air Changes per Hour (ACH)

Reference Presets

Q = n × V (air changes × room volume)

Required Ventilation Rate

27.0 m³/h

= 7.5 L/s

Equivalent Air Changes

0.50 ACH

Japanese Building Code

COMPLIANT

Residential 24h ventilation: minimum 0.5 ACH required (Building Standards Act)

Current ACH: 0.50 ACH

Suggested Fan Capacity

1.2x required (with margin)32 m³/h

1.5x required (generous margin)41 m³/h

Formula

Q = n × V = 0.5 × 54.0 = 27.0 m³/h

Air Changes Reference