Environmental quality of university classrooms: Subjective and objective evaluation of the thermal, acoustic, and lighting comfort conditions

Questionnaires are an important tool for analyzing the thermo-hygrometric, acoustic, and lighting conditions of indoor environments. In the present work thermal, acoustical, and visual conditions were investigated through both subjective and objective measurements carried out in 7 classrooms at the University of Pavia, Italy. Measurements of the main descriptors of thermal, acoustical, and visual comfort were carried out and new specific questionnaires were purposely developed, in order to investigate the students' perception on acoustic and lighting comfort and to analyze which are the subjective parameters most correlated with the experimental results. Both 7-value and 13-value scales were provided to the occupants for the thermal comfort evaluation and no significant differences in the results were found. Among all the acoustic comfort questions, the ones related to background noise present the highest correlation. Other questions were selected considering the intelligibility comprehension and the overall assessment of the auditory environment in the classrooms. Classroom 5 is the worst in terms of acoustic conditions and it is confirmed by the correspondent indexes named IBN and ISQ. The analysis of the lighting questionnaire showed that the average measured illuminance value has a high correlation with the perceived visual comfort. The classrooms annoying glares have a strong relationship to the classroom excessive light contrasts and a good correlation with the measured illuminance values. Among the acoustic and lighting questionnaires, ten questions with the best correlation with the experimental results were chosen and ten indexes were proposed, in order to describe the comfort conditions.