The effects of night ventilation technique on indoor thermal environment for residential buildings in hot-humid climate of Malaysia

This study investigates the effectiveness of night ventilation technique for residential buildings in hot-humid climate of Malaysia. This paper firstly presents the results of a survey on usage patterns of windows and air-conditioners in typical Malaysian residential areas. Secondly, the effects of different natural ventilation strategies on indoor thermal environment for Malaysian terraced houses are evaluated based on the results of a full-scale field experiment. The results show that the majority of occupants tend to apply not night ventilation but daytime ventilation in Malaysian residential areas. It can be seen from the field experiment that night ventilation would provide better thermal comfort for occupants in Malaysian terraced houses compared with the other ventilation strategies in terms of operative temperature. However, when the evaporative heat loss of occupants is taken into account by using SET*, the night ventilation would not be the superior technique to the others in providing daytime thermal comfort mainly due to the high humidity conditions. Therefore, the indoor humidity control during the daytime such as by dehumidification would be needed when the night ventilation technique is applied to Malaysian terraced houses. Otherwise, full-day ventilation would be a better option compared with night ventilation.