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AHU Selection

AHU selection and configuration

AHU configuration

Our AHU selection guide enables you to rapidly select the appropriate unit size for a specific project requirement.  

Simply, select the velocity and volume (or next highest value) required from the table. Then, locate the unit size, external width and external height from the left hand column. Finally, add the base height to the external unit height and 50mm for a pitched roof if the unit will be sited in an external location.

Please note that dimensional restrictions may dictate a higher velocity of around 3m³/s. This, however, is likely to mean that the AHU specific fan power will exceed Building Regulations requirements. Subject to external static pressure and internal components, Building Regulations requirements may be met at an AHU velocity of 2m³/s.

If the image doesn't display correctly or you wish to download the guide as a PDF please use the link below:

AHU sizing calculation guide (matrix below as a .pdf file)

Our AHU sizing guide enables you to rapidly select the appropriate unit size for a specific project requirement


Approximate Length of Air Handling Unit Components for Unit Size (.pdf)

Approximate Weight of Air Handling Unit Components for Unit Size (.pdf)



Contact our AHU sales engineers for further assistance