Envelope retrofits for enhancing thermal comfort in detached houses in hot semi-arid climatic conditions: A year-long monitoring and simulation study

Abstract

Retrofitting residential buildings could substantially reduce the sector's energy and carbon footprint and provide significant economic benefits in the long run. Building retrofits must be urgently developed and promoted in India, where most residences are constructed without any consideration of energy efficiency due to the lack of a mandatory residential energy code. However, building retrofits must be devised considering the local construction practices and climatic conditions since an improper retrofit can deteriorate the indoor environment and even increase the building's energy consumption. Therefore, through year-long monitoring and simulations of the comfort conditions of a room inside a detached single-story house, this investigation evaluated different envelope retrofit options for improving it in India's hot semi-arid climate.The results showed that the room's indoor environment (without the retrofit) was comfortable for only 26–43 % of the year, depending on the room's configuration, with the roof being the major contributor to the heat gain and the floor and external walls largely contributing to heat losses. The comfort duration increased by 6–21 percentage points annually by applying cool/super-cool roof paints since they significantly reduce the roof's heat gain. Similar comfort enhancements could also be obtained by insulating the roof or the entire envelope, mainly due to reduced roof heat gains. However, insulating the walls alone deteriorated the comfort conditions since it became difficult for the heat to escape the room. Overall, applying cool/super-cool roof paints was recommended over other studied options since they provide substantial comfort benefits with low cost and easy implementation.