An Energy Performance Evaluation of Commercially Available Window Glazing in Darwin’s Tropical Climate

A total of 40% of the world’s energy produced is utilized to maintain thermal comfort for the occupants of the building. Governments are taking measures collectively to regulate energy efficient buildings to reduce carbon emissions globally. Windows account for more than half of total energy losses in the buildings. The employment of energy efficient glazing in the construction in-dustry is not common in Australia. This paper investigates several types of commercially available windows and their effectiveness in the hot and humid climate of Darwin. Although extensive liter-ature is available for cold regions, these windows have not been studied in hot and humid climates such as the climate in Darwin. Building cooling loads of an academic building were calculated using Autodesk Revit Architecture and Carrier HAP. Double glazed variants offered approximately a 5% reduction in cooling loads and had a payback period of nearly 7 to 9 years, depending on the type of gas used to fill the pane cavity. The results indicate that triple glazed, or aerogel-based windows will provide about 11–12 % of energy saving in cooling loads. These can be a viable alternative and have a payback period of 11 years, while their average service life expectancy is 30 years. It was found that the feasibility of efficient glazing depends on market price, building usage, and energy efficiency of an overall building envelope.