LAUSR

This paper investigates the effect of an existing facade’s construction (viz. clear/grey/solar film, with and without external shade) and orientation on the performance of low-e (hard coat)-based retrofit double glazing in a tropical climate. The performance of double-glazed facades is characterized by the ability to reduce solar heat gain and the consequent reduction in power consumption of air-conditioning systems. This study involves a real-life test-bedding of a low-e (hard coat)-based retrofit double-glazing facade for a few specific cases—clear glass southeast facade without shade, clear glass southwest facade with external shade, and northwest facade with solar film and external shade. Subsequently, energy modelling simulations were done to analyze other scenarios involving various combinations of facade orientation (north, south, west, and east) and facade material (clear glass, tinted grey glass, clear glass with solar film) with and without external sunshades. The east/west-facing facades had a higher impact on the retrofit solution, and more so when the existing facade was of tinted glass or with solar film. For the case analyzed, with a window-to-wall ratio of 8% (based on overall building envelope), a grey tinted east-facing facade could benefit from annual average HVAC energy savings of up to 5.9%.