Indoor thermo-photometric occupant’s evaluation: what lies beneath perception, discomfort and preferences?

Modern building occupants are hedonistic individuals who tolerate little discomfort, leading to inappropriate use of HVAC systems. Re-examining occupants to understand how they form their opinions on their environment is crucial for identifying new pathways to frugality. Comfort is often categorized in literature, with current standards segmenting the evaluation of individuals based on their perception, discomfort, and preference. However, studies need to corroborate the necessity of this division or the relationships governing these aspects.

This article aims to inspire and motivate by exploring the link between these three aspects through a new experimental approach. This innovative approach is focused on evaluating the participants’ experimentation of thermo-photometric ambiance, a unique perspective that we believe will inspire further research in the field. It involves the simultaneous measurement of physical parameters related to thermal and photometric environments and the interaction between these two sensory modalities. These data are also associated with individual physiological parameters and psychological parameters obtained from synchronous questionnaires. The study involved 133 students in a learning situation, in a naturally ventilated classroom with high autonomy in natural lighting.

Our analysis utilizes factorial analysis tools (PCA, CA, and MFA) to process the extensive database. Our results corroborate the conclusions of the literature, notably the observation of the “one-vote veto” phenomenon, indicating general discomfort as soon as one of the sensory modalities is in discomfort. Additionally, our study advances knowledge in the field by statistically demonstrating the robust inverse correlation between thermal perception and thermal preference.