Fundamental Research on Sustainable Building Design for the Rural Elderly: A Field Study of Various Subjective Responses to Thermal Environments and Comfort Demands during Summer in Xi’an, China

Well-designed residential thermal environments that meet the comfort and health needs of elderly individuals can enhance their well-being and decrease associated health risks, which is one of the foundations of sustainable building development. However, limited evidence on thermal response patterns and thermal comfort needs of rural elderly leads to insufficient support for improving thermal environments. This study was conducted in seven villages in Xi’an, a cold region of China, and both subjective questionnaires of thermal comfort and objective physical environment tests were adopted. Correlations between nine kinds of human subjective responses and thermal environmental parameters were examined. The neutral values of operative temperature, relative humidity, and air velocity were calculated to be 23.9 °C, 63.3%, and 0.28 m/s, respectively. Comfort ranges for temperature, humidity, and air velocity were determined to be ≤29.3 °C (80% acceptability), 43.3–81.0% (80% acceptability), and 0.16–0.41 m/s (90% acceptability). Clothing insulation of rural elderly in summer was relatively higher and less sensitive to temperature shifts. The slope value of the thermal adaptative model was larger, with higher comfort temperatures in warmer environments. These results are the outcome of the prolonged adaptability to the regional climate and the poor indoor thermal environment, as evidenced by lower psychological expectations, higher behavior adjustment, and environmental decisions influenced by household low income. The findings in this study can be used as a basis for the design or improvement of residential thermal environments for rural older adults.