On the Interaction between Lighting and Thermal Comfort: an Integrated Approach to IEQ

A sustainable building design should be compliant with the even more pressing energy saving requirements - as in NZEB - and high levels of Indoor Environmental Quality. Despite it is accepted that different facets of IEQ could have antagonistic effects on building energy demand, relatively few studies are aimed at investigating the mutual interaction among its four components. From this point of view, the hue-heat hypothesis is based on the idea that light and colors can affect the thermal perception. Particularly, spectral power distributions of light shifted to short wavelengths seem to promote a cooler thermal perception and vice-versa. To verify this still debated hypothesis, this paper is focused on a subjective investigation carried out in a special mechanically conditioned test room provided with white-tuning LED sources. 163 volunteers have been exposed to two different lighting scenarios characterized by warm (3000 K) and cool lights (6000 K) at a fixed work-plane illuminance value (300 lx) at two different operative temperature values (20 °C and 25 °C). Obtained results seem to confirm that warm light results in a warmer thermal sensation. Probably due to thermohygrometric conditions relatively close to comfort, no effects on thermal evaluation, and thermal preference were found under both microclimatic scenarios. This was also about the effects of CCT on humidity perception and game performances