Investigating the effects of climate on thermal adaptation: A comparative field study in naturally ventilated university classrooms

•Adaptive strategies in relation to climate differences were quantified.•1377 questionnaires were collected during the heating season.•Neutral, comfort, and preferred temperatures varied in relation to the climate.•Climate-dependent adaptation is evident from the comparison with the PMV-PPD model.•Adaptation can be deployed during the winter period to reduce consumption. In educational buildings, adaptive strategies can be adopted for the achievement of thermal comfort and reduction of energy consumption. Since climate can largely affect thermal comfort, there is a need for understanding its role in the definition of different adaptive capacities, thermal neutrality, comfort, and preference. To this end, 17 naturally ventilated university classrooms from 10 different buildings located in two sub-climates of Italy (Mediterranean climate) and France (Continental climate) were analysed. In total, 1377 questionnaires associated with environmental parameters were collected. The same educational stage (i.e. university classrooms) and operation mode (i.e. naturally ventilated during the heating period) were investigated to remove possible biases related to their influence on thermal comfort perception. Field studies show that despite French students performing less adaptive actions, their neutral temperature (TN) was 3.1 °C lower than the Italian ones (TN,ITALY = 23.6 °C and TN,FRANCE = 20.5 °C) and this difference was statistically significant. Adaptation as a function of the sub-climate was evident from the comparison with the PMV-PPD model. Neutral temperatures calculated with PMV were higher than those obtained from TSV, and the difference increased for the French colder climate. Practically, students’ adaptation to colder environments can be deployed to ensure comfort while reducing the heating demand.