People's behaviour in choosing optimal thermal places for sustainable lifestyle: Reducing air-conditioning use in tropical climates

In humid tropical climates, the passive behaviour of residents contributes to the reduction in energy consumption in the same way as passive designs contribute to energy saving. We measured the thermal environment in Surabaya, Indonesia, and conducted interviews with its residents to determine which rooms and terraces they freely select as their ideal environment. The results showed that the residents change locations on the basis of what they think are comfortable environments in the house at different times of the day; for example, they stay on the 1st-floor northern terrace in the morning and the 2nd-floor southern terrace in the evening. On the 1st-floor northern terrace, the temperature does not increase in the morning because of the shade and large thermal mass of its concrete floors and increases at noon because of the reflection of solar radiation. In the evening, the temperature of the 2nd-floor southern terrace drops more quickly and below that of the 1st-floor northern terrace because of higher winds. Thus, the thermal environments in selected locations in the house are more comfortable than in other locations. Choosing a comfortable location in the house reduces residents' use of air conditioning and contributes to energy saving.