Behavioural adaptation and the use of environmental controls in summer for thermal comfort in apartments in India

Building energy use in India is rising phenomenally. Indian codes prescribe a very narrow comfort temperature range (23-26 degrees C) for summer. Ventilation controls alone consume 47% of total energy in residences. Thermal comfort field studies in Indian residences were not attempted. The author conducted a field study in apartments in Hyderabad, in summer and monsoon seasons in 2008. This paper presents the occupants' methods of environmental and behavioural adaptation and impediments in using controls. Only about 40% of the occupants were comfortable in summer due to inadequate adaptive opportunities. The comfort range obtained in this study (26.0-32.5 degrees C), was way above the standard. Fanger's PMV always overestimated the actual sensation. The occupants used many adaptation methods: the environmental controls, clothing, metabolism and many behavioural actions. Use of fans, air coolers and A/cs increased with temperature, and was impeded by their poor efficacy and noise, occupant's attitudes and economic affordability. A/c and air cooler usage was higher in top floors. Behavioural adaptation was better in summer and was restricted in higher economic groups always. Thermal tolerance was limited in subjects using A/cs and resulted in "thermal indulgence". This study calls for special adaptation methods for top-floor flats. (C) 2010 Elsevier B.V. All rights reserved.