Variation in thermal, visual and overall comfort evaluation under coloured glazing at different temperature levels

Within the scope of a broader research project about daylight and temperature interaction effects on human responses, this paper investigates how daylight transmitted through spectrally selective glazing (blue, orange and a reference neutral) affects thermal comfort of occupants (cross-modal effect of daylight colour), besides the more conventional visual comfort. Similarly, the effect of indoor thermal conditions on the visual comfort evaluation of the transmitted daylight is investigated (cross-modal effect of temperature), as well as that of the combined effect of daylight and temperature on overall comfort. To this end, different analyses are conducted on the dataset collected through experimental investigations in an office-like test room involving a total of 75 participants. Three main conclusions can be drawn from the results of this work: (i) Symmetrical cross-modal effects occur between daylight colour (i.e., daylight transmitted through spectrally selective glazing) and temperature. (ii) Differences in overall comfort evaluations under both blue and orange glazing in comparison with those under the reference glazing are larger in a thermally uncomfortable environment compared to other more comfortable thermal conditions. (iii) Results of spearman correlations show that overall comfort is positively and equally correlated with both visual and thermal comfort evaluations. Based on these results, it can be stated that in the presence of glazing with a colour tint, thermal perception evaluations should be investigated together with the most common visual ones. Moreover, thermal conditions should be considered in parallel with visual ones as visual and overall comfort might be affected by their combined presence.