An experimental investigation on the effect of lighting colour of localized radiant panel thermal comfort system

This study investigated the effect of different correlated colour temperature (CCT) lighting on perceived thermal comfort in a simulated domestic environment with radiant heating. A prototype with adjustable CCT lighting (4000K neutral, 1800K warm, 6500K cold) alongside electric radiant panels was installed in an environmental chamber set to 18 °C. The investigation involved sixty participants who each underwent 30-min exposure sessions to one of the lighting scenarios in a blinded setup, during which they filled out thermal comfort questionnaires at predetermined intervals. Overall, the findings revealed satisfactory comfort levels, with average global comfort votes of “good” and 82.32 % thermal acceptability, across scenarios. The radiant heating prototype successfully maintained thermal comfort in the less-conditioned space. Looking at the different lighting scenarios, the “warm” lighting initially provided the highest thermal comfort, aligning with the hue-heat hypothesis, with global comfort votes of 1.13, compared to 0.96 for “neutral” and 0.78 for “cold” after the first 10 min. However, differences became less pronounced over time. Contrary to hypotheses, the “cold” lighting scenario did not reduce comfort compared to “neutral”. Moreover, Participants indicated greater thermal satisfaction under “warm” lighting. Although changes in lighting CCT did not drastically alter thermal perceptions, they did have a subtle influence on comfort, particularly during the initial stages of the experiment. This finding suggests the need for further research into how visual and thermal comfort interactions can be optimized.