The importance of the air handling unit in the system is readily understood, as it modifies the air conditions of air conditioned environments. Both the construction layout and the physical location of the installed air handling unit are extremely difficult to adjust at a later date. For this reason, the equipment must be carefully and precisely selected and installed.

The type of fan and the motor can be selected on the basis of designed static pressure and efficiency requirements. The characteristics of the cooling and heating units can be defined on the basis of estimated cooling and/or heating load.

Energy saving devices such as Heat wheel, Heat pipe etc. can be selected as and where advantageous without wasting valuable costs. Suppliers of components are qualified only if they have proven track record of supplying and can supply spares even after many years of purchase.