Adaptive Thermal Comfort in the Naturally Ventilated Offices of Cold and Cloudy Climate of North-East India

Buildings consume 40% of generated energy and impact the occupants’ thermal comfort and energy efficiency. Adaptive thermal comfort studies provide in-depth insights into the adaptation characteristics of occupants, building operation, functionality, and sociocultural context, providing building designers and architects with greater flexibility to design energy-efficient and climate-responsive buildings that offer optimal thermal comfort. This study was done in Shillong by carrying out thermal comfort surveys from July 2016 to June 2017 of 65 naturally ventilated offices in Shillong. A total of 767 valid questionnaires (396 male and 371 female subjects) were collected following ASHRAE class II protocols. The analysis of the collected data shows that the estimated neutral temperature for Shillong offices is 23.4 ºC with a preferred temperature of 22 ºC and a preferred relative humidity (RH) of 62%. Notably, a 2.2 °C change in globe temperature alters the thermal sensation, indicating greater sensitivity to temperature change and requiring lower thermal stimuli in Shillong, reflecting low thermal inertia and rapid behavioural adaptation. Regardless of extensive indoor temperature variations (13.6 ºC–28 ºC), RH of (26%–81%), significant subjects reported a comfort temperature span of 20.5°C–25°C, emphasizing the distinct climate of Shillong.