Saving energy with light? Experimental studies assessing the impact of colour temperature on thermal comfort

Testing took place in a climate chamber. In Study 1, comfort ratings were collected using thermal comfort surveys (N = 32). In Study 2, an observational design was used, where changes in clothing level, interpreted as thermal discomfort responses, were observed (N = 32). We compared comfort ratings and changes in clothing level under light with a colour temperature of 2700 K vs. 6500 K. Results partly confirmed the hypotheses: both self-report and observation indicated higher comfort under the low colour temperature. Further research will need to replicate findings in a real-world setting to see if light might indeed be a tool to modulate thermal comfort, and hence reduce usage of heating and cooling.