Analysis of determining factors in the thermal comfort of university students. A comparative study between Spain and Portugal

The quality of the indoor thermal environment is essential because of its impact on the energy efficiency of buildings and on the health and well-being of those who occupy them. This is particularly important in educational buildings because of the direct impact on student performance. Various factors, such as natural ventilation, have become particularly relevant since COVID-19. Although this measure is no longer mandatory, its usefulness has been proven, and it is therefore interesting to evaluate it to understand its impact on thermal comfort in classrooms. In addition to ventilation, other aspects such as clothing, gender and habits can also influence the thermal perception of the occupants. Therefore, this study investigates the impact of these factors on thermal comfort in university buildings in Spain and Portugal through a campaign of measurements and questionnaires. The results showed that, according to CO2 concentrations, natural ventilation strategies have been maintained more in Spain than in Portugal. Also, these protocols did not have a negative effect on the thermal comfort of the occupants. On the other hand, there were significant differences between the student's responses in the two countries. In fact, Portuguese students showed warmer preferences (Tn = 26.40 degrees C) than Spanish students (Tn = 24.70 degrees C). Finally, clothing habits were a crucial factor in the perception of thermal comfort, with differences by country and by gender.