A strategy for effectively utilizing occupants’ adaptive behaviors (OABs) to achieve thermal acceptability while maintaining low energy consumption is necessary. This study aims to clarify the relationship between OABs and thermal acceptability over various climate zones, as well as the change in OABs due to air conditioner (AC) ownership in Indonesian residences. An online questionnaire consisting of perceived OABs’ time intensity, thermal acceptability, and personal attributes from 3000 respondents across Indonesia was analyzed using logistic regression. The results suggested that NV occupants engage in more fan usage and window opening to enhance ventilative cooling, while AC occupants are more likely to adjust clothing and use portable fans to create cooler environments. Moreover, the effects of OABs on NV residences varied depending on the local climate conditions. In hot local climates, averages of 90% fan usage intensity and 92% window opening intensity, complemented with active clothing adjustment, were unable to effectively provide thermal acceptability. These findings imply that there is a range of indoor environmental conditions in which conventional OABs work well. This study highlights the need to promote behavioral adaptations, especially in AC mixed-mode buildings, and to consider behavioral adaptations in NV buildings based on local climates.

Occupants’ adaptive behaviors (OABs) can boost thermal acceptability. This study aims to identify the OAB pattern in the hot-humid region of Indonesia and compare the thermal acceptability percentage of the groups with the identified patterns. Data from an online questionnaire with 3000 respondents were adopted for the analysis of air conditioning (AC), fan, and portable fan usage intensities, along with AC set-point temperature, clo-value, clothing adjustment, and window opening intensity. Hierarchical cluster analysis and logistic regressions were used to distinguish and evaluate OAB patterns. Five groups with various patterns for each AC and naturally ventilated (NV) residence were identified, and similar pattern groups with high clo-values and low thermal acceptability percentages appeared in both residences. The highest window opening intensity for the most active patterns in both AC and NV residences was perceived to be 87% and 91% as time intensity averages. These findings imply a great influence of NV lifestyles with active behavior patterns on improving thermal acceptability for both residences. This study suggests an appropriate OAB strategy to promote a better trade-off between energy consumption and thermal acceptability, such as patterns with a ±25 °C set-point temperature and various OABs in AC residences. Additionally, further investigation into the socio-cultural effect of OABs is necessary.

Good sleep is essential for a healthy life. While airflow improves sleep in a hot environment, it may cause an excessive drop in body temperature because thermal-adaptive behavior is inactive during sleep. This study aims to propose an airflow control theory that prevents the excessive drop in body temperature while maintaining good sleep. The theory changes the heat transfer coefficient between the skin and the environment by the intensity of the fan operation to maintain a heat loss of 30 W/m² from a body with a skin temperature of 34.5 °C in a temperature-changing environment. We fabricated a ventilated sleep capsule in which this theory was embedded. Thermal manikin experiments were conducted to obtain the relationship between sensible heat transfer coefficients and the fan operating signal to establish control equations. We conducted a case study to evaluate whether the theory provided better sleep than sleeping with a regular fan running freely in homes in Ueda City, Japan, in one summer. Although the data used in the analysis were from only three subjects, the statistical analysis showed that sleeping in the ventilated sleep capsule provided better sleep, with a mean of 6% better sleep efficiency.