Thermal expectation: Influencing factors and its effect on thermal perception

Abstract Thermal expectation is mentioned as one aspect of psychological adaptation to indoor thermal conditions. However, there is a lack of studies in the built environment assessing expectations directly and the relationship between expectations and thermal perception. Therefore, this paper studies potential influences on occupants’ expectations of indoor thermal conditions and the implications of their expectations on thermal perception. A combination of data from laboratory and field studies was analysed, where the same 47 participants participated in both of them. Subjects experienced different temperature conditions and were asked directly about the congruence between their thermal expectations and actual experience together with their actual thermal perception. The question regarding participants expectations applied in this study can be considered as the most straightforward way to ask for their expectations. The data was analysed by ordinal mixed effect regression analysis. Results show that there is a significant influence of the level of expectation on thermal sensation and comfort votes for the field and laboratory study. Indoor temperature, the day of experiment (first, second, or third) and the location (laboratory vs. field) show significant influences on thermal expectation. However, participants state their expectation of the indoor environment independent of the outdoor conditions or indoor-outdoor temperature difference. The discussion of implications of these results for adaptive approaches of room conditioning, which relay on the acceptance of higher fluctuations of indoor thermal conditions, suggests to carefully address expectations in future studies.