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Air Changes per Hour Calculator

Estimate air changes per hour from room volume and supply flow in litres per second.

 

 

ACH

About this calculator

Use this calculator to check ventilation of a room. Enter the room volume in cubic metres and the supply flow in litres per second.

ACH = (flow in m³/s × 3600) ÷ volume, with flow converted as L/s ÷ 1000. Volume stays in m³; flow stays in L/s. There is no m³ or L/s unit picker in this calculator.

This is a well-mixed-room estimate. It does not model short-circuiting, occupancy, or a filter.

Volume (m³): Room volume in cubic metres.

Flow (L/s): Supply airflow in litres per second.

ACH: Air changes per hour.