Dehumidifying load remains the largest contributing load to total cooling load in hot humid tropical climate. Minimizing dehumidifying load at a low cost in a new building design and existing building in developing country comes with design challenges. This paper uses ESDL TAS building simulation software to perform dynamic simulation of whole office building envelope using weather sensitive variables for parametric study. Significant findings are: a. The total dehumidifying load of the base case was reduced by 55% with a corresponding reduction of 45 % of the total cooling load by the following significant strategies: i. Changing the thermostat temperature and relative humidity setting to 26°C and 60% respectively. ii. Reducing infiltration arising from all leakages to a practically feasible minimum of 0.20 ACH as well as ventilation gain of 1 ACH. b Vapour diffusion property of building materials had insignificant effect on minimizing the dehumidifying load. The following were concluded: 1. There is no single approach in minimizing dehumidifying load and maintaining indoor environmental building performance. 2. ESDL Tas, is inadequate software package for predicting vapour diffusion. Finally, dehumidifying load of air-conditioned buildings in hot humid climate in developing country can be minimized at cost effective approach by changing the weather dependent variables (ventilation gain, thermostat setting and infiltration gain).