The most commonly used building materials were reviewed concerning their impact on cooling load and architectural interventions. The continuing increase of energy consumption of air conditioning systems suggests a more profound examination of their tropical climatic environment and the impact on the building and an application of passive cooling systems. Furthermore, in this study, mathematical expressions were developed to support decision-makers to select their optimal envelope enhancement strategies for buildings under tropical climatic conditions. Moreover, an economic analysis was also carried out to help prospective users with their energy-saving ideas. Out of selected materials, glass was found to be the most influential material, followed by timber and wall. The results obtained in this study reveals that improvement of material and their impact on energy conservation, especially double glass window over the plain glass window per 100 m2 area, contributes to reducing the overall 22% monthly electricity bill and their AC capacity. Moreover, this study further reveals that improvement of the wall conserves a significant amount of energy; Improved wall over one layer brick wall per 100 m2 area contributes to reducing overall energy by 12 % of their AC capacity and monthly electricity bill. The primary object of this research is to study the impact of internal & external factors in building energy consumption under tropical climatic conditions. There are few specific objectives identified to fulfil the main objective. Firstly, the study tries to identify the impact of building cooling load for different building orientations with the most commonly used building materials and their optimisation. Then develop a mathematical equation and graphs for cooling load and their impact of most common use building materials under tropical climatic conditions. Furthermore, this research identifies the direct impact of the capacity of the air conditioning unit and their electricity consumption for RSCL. Finally, find out the payback period for different improvements of exterior walls through economic analysis.