Estimate the air flow needed to ventilate a factory, warehouse or workshop using the air-changes-per-hour method, and the number of roof ventilators required.
Estimate only. Results are indicative, based on the values you enter and simple standard methods. Always confirm with the product datasheet, applicable codes and a qualified engineer before design or purchase.
How the calculation works
Required air flow (m³/h) = building volume (length × width × average height) × air changes per hour. Dividing by the rated capacity of one ventilator gives an indicative number of units.
Choosing air changes per hour
The ranges shown in the calculator are typical guideline values. Heat load, occupancy, process fumes, local climate and regulations all affect the right figure, so confirm with a ventilation engineer. Ventilator capacity also depends on wind speed or motor rating — use the value from the manufacturer’s datasheet for your conditions.
