Temperature-colour interaction: is colour affecting people’s thermal perception?

Over the last century, a large number of studies has tried to answer to the question whether coloured stimuli could have an effect on human thermal perceptual evaluation (i.e., temperature-colour interaction). In the building research area, this effect is referred to as the “hue-heat-hypothesis” (HHH) and has gained attention due to the fascinating idea of heating and cooling with colours. After a brief digression on previous studies on HHH, this presentation focuses on two experimental studies carried out recently at LIPID, EPFL. In both studies, temperature and colour are manipulated to assess the thermal evaluation of people taking part in the experiment. In the first study, colour is changed thanks to coloured filters applied on the windows of a test room, resulting in transmitted “coloured” daylight. In the second study, projected HDR photographs of the same room are displayed in the Virtual Reality headset, to control for the variability of daylight through time of the day and weather experienced in the first study. Results of both experiments confirm that colours have an effect on thermal perceptual evaluation of people, with blue leading to a “cooler” sensation and orange to a “warmer” one.