With worldwide energy cost rising significantly, there has been a pressing need to reduce the burning of fossil fuels and subsequently energy consumption. This, coupled with the prospect of global warming threatening human habitation, has made countries including Singapore more conscious and aware of the energy problem at hand. This paper deals with smart window, a double glazing unit where one pane consists of a high-performance heat reflective glass and the other coated with low-emissivity (low-e) coating. This combination of glazing provides optimum energy efficiency and a high level of daylight transmission with minimal reflectance. A study is made on the benefits derived from smart window done on a hypothetical 20-storey building. This encompasses a description of its quantitative impact on cooling load, energy consumption and energy savings achieved as compared with other forms of glazing. Following this, a detailed life cycle costing is done to determine the economic benefits attained from this type of glazing. The reduction of atmospheric pollutants as a result of using smart window is also analysed, and the future application of the glazing in hot and humid climates is discussed. In conclusion, it is observed that the smart window meets the technical and economic targets set, thus making it a viable long-term investment for high-rise commercial buildings.