Comparison of Cost Benefits of New Installation and Retrofitted Rainwater Harvesting Systems for Commercial Buildings

Abstract

This paper aims to evaluate cost benefits of new installation and retrofitted rainwater harvesting system (RWHS) for commercial building. The selected commercial building is AEON Taman Universiti, Johor, Malaysia. Daily rainfall data were obtained from the Senai International Airport station. The mass balance model was adopted for the simulation approach. Several economic parameters, namely, net present value (NPV), return on investment (ROI), and benefit-cost ratio (BCR) are used for the evaluation. Maximum NPV, BCR, and ROI of the new installation RWHS are 1.9, 1.5, and 5.5 times higher, respectively, than those of the retrofitted RWHS. It is concluded that new installation RWHS provides more economic benefits compared to the retrofitted RWHS.