Exploring Floor-Sitting as Adaptive Behavior in Tropical Apartment Residents: Regional and Indoor Climatic Influences in Indonesia

In the tropical climates of Southeast Asia, the growing reliance on air conditioning (AC) for space cooling not only increases household energy consumption but may also diminish the role of culturally rooted adaptive behaviors such as floor-sitting. This study aims to explore the interaction between climatic factors, including regional and indoor climates, and thermally adaptive behaviors in Indonesian apartments, with a focus on floor-sitting. First, a large-scale questionnaire was conducted to analyze these interactions among different regional climates. Second, in-depth indoor climate measurements and a point-in-time questionnaire were conducted among the residents in the hotter regions. In the hotter regions like Jabodetabek (Jakarta metropolitan area) and Surabaya, floor-sitting was primarily conducted without using AC, often alongside fans in low-rise housing. In the cooler region of Bandung, floor-sitting was a common adaptive behavior with window openings in both high-rise and low-rise buildings. The in-depth measurement showed that low-rise buildings using higher thermal mass materials maintained stable indoor conditions for both air and floor temperatures even in the hotter region. The respondents could obtain coolness and remain thermally comfortable through a floor-sitting posture without using AC, especially when air and floor temperatures were both less than 31 °C. These results demonstrated that floor-sitting is a vital behavior that adapts to regional and indoor climatic conditions in the tropics while achieving thermal comfort and relying less on AC devices.