Set point temperature and adaptive principle

Various countries have introduced a higher indoor set point temperature for offices to conserve energy. The typical set point temperature in Japanese offices is 26°C, but that of offices in the USA is much lower. This study aimed to reveal the historical transition in office thermal environments in Japan and other countries. According to a literature review, the design temperature of Japanese offices has been kept almost constant since the 1950s, when air conditioning systems and the design conditions were introduced to Japan from the USA. However, in the USA, the design temperature was later lowered for the summer. According to a database of field measurements in Japan, the indoor temperature was slightly higher in the 2000s than in the 1980s. The socioeconomic context has a significant influence.