Unravelling Intraindividual Variability in Thermal Comfort: Daily, Monthly, and Seasonal Patterns – REPHEAT

Thermal comfort is one of the key determinants of Indoor Environmental Quality and a major contributor to building energy consumption and carbon emissions globally. As such, research on thermal comfort can significantly impact the sustainability of our built environment and the health and well-being of our society. While most thermal comfort studies have focused on understanding and modelling the processes governing average sensory responses, there are notable individual differences in how we, as humans, perceive our thermal environment. The REPHEAT project aims to bridge this gap by investigating patterns of intraindividual variability in human thermophysiology, thermal perception, and thermal behaviour over the day (circadian rhythm), the month (menstrual cycle in women), and the season (thermal acclimatisation) under warm conditions. To achieve these objectives, the project will adopt an interdisciplinary approach by bringing together experts from the fields of building physics, neurophysiology, and epidemiology. We will use an experimental methodology with a repeated-measures design, where participants will be exposed to repeated warm conditions at different times of the day, month, and season in a controlled "living lab". The lab will replicate a real office, equipped with high-quality instruments to conduct physical, physiological, and subjective measurements with high spatial and temporal resolution. The results will expand our fundamental understanding of the factors driving intraindividual variability in thermal comfort and enable improvements to existing thermoregulatory and thermal perception models. Insights into how time of day, month, and season influence thermal comfort and behaviour will help develop innovative, human-centred building control strategies, enhancing both comfort and energy efficiency in buildings.