Children's thermal comfort in school classrooms: Influence of contextual factors, thermal experience, and diurnal variations

In recent years, there has been growing interest in children's thermal comfort, which is partly attributed to research findings on children's lower comfort temperatures compared to adults and to the occurrence of more frequent and longer heatwaves. This paper explores the influence of contextual factors on children's thermal perception by comparing field survey results from Swedish grade school classrooms with findings from previous studies in the UK that followed the same study design. The Swedish dataset consists of 2116 questionnaires, collected from approximately 160 children aged 9–11, across 90 surveys conducted during both the heating and non-heating seasons. The results confirm the previously observed discrepancy between children's reported thermal sensation and both the Predicted Mean Vote (PMV) and the adaptive comfort models, with children's comfort temperature being lower than predicted. However, the children in this study were highly adaptive and more so than those in the UK study, with a unit change in thermal sensation vote in the non-heating season corresponding to 5 °C change in operative temperature. Regarding diurnal variation in thermal perception, children reported higher thermal sensation in the afternoon at the same operative temperature and preferred a cooler environment, with no change observed in clothing insulation. This research highlights the importance of contextual factors- such as school policies, culture and indoor climate experience- on shaping thermal comfort trends, and emphasises the need for further research on adaptive comfort of schoolchildren in different contexts.