Blow-through (BT) and draw-through (DT) modes are the two common types of air handling unit (AHU) configurations that are prevalent in heating ventilation and air conditioning (HVAC) systems in existence. The arrangements of a supply fan and a cooling coil in these systems have advantages on each other in terms of cooling coil loads, moisture removal and noise levels. In the present work, a simple equipment load formulations for the two modes are shown, which may be used by designers for early diagnosis and decision making. From the comparison of derived loads for a cooling-dehumidifying chilled water coil, it is proved that DT type AHU shows higher cooling load than BT type, when supply air temperature from both these types of AHU is same. It is also seen that the difference between these coil-loads are actually affected by the AHU inlet condition and fan heat addition. An early choice between a DT and a BT system based on usage and requirement saves a lot of future hassles and untimely retrofits. (C) 2013 Elsevier B.V. All rights reserved.