Enhancing Thermal Environment Quality with Voids and Indoor Gardens as a Passive Design Strategy towards Sustainable and Healthy Living

Subjective evaluation plays an important role in assessing indoor thermal quality (ASHRAE-55). This study assesses the physical and pyschological aspects of thermal comfort in two modified rooms, namely the Department of Architecture Universitas Muhammadiyah Jakarta (UMJ) Building Technology Laboratory (Room A) and the Architecture Student Community “Fathirista” Room (Room B). Both rooms have similar microclimate factors (humidity, temperature, radiation and air velocity) were distinguished as one of the room was modified with an additional void and indoor garden space, while another room would be only added indoor garden space. In the experimental process, four types of modification were applied to both rooms. 26 students, who were familiar with the indoor climate environment of the modified rooms, were then asked to experience the four thermal condition modifications and to describe them by completing a Likert scale questionaire as a subjective evaluation step. Through this semi-experimental research, the aim was to discover different levels of thermal comfort experience through a perceptional study as an interpretation of subjective evaluation. The second purpose was to establish whether voids and indoor gardens could significantly affect thermal comfort. The data were analysed with SPSS software, with the results showing that the modified rooms with a void and additional indoor plants (Room A) was the most comfortable room according to the respondents’ subjective evaluation. Even though the respondents had experienced the same thermal environment for years, they had different subjective evaluations towards the four modified conditions.