Combined effects of acoustic, thermal, and illumination conditions on the comfort of discrete senses and overall indoor environment

Humans perceive environments through the interaction and integration among various sensory stimuli. While research on multisensory interaction research has increased over the last few decades in the fields of cognitive neuroscience and neurophysiology, the effect of multisensory interaction on indoor environmental perception, including thermal comfort, acoustic comfort, visual comfort, and indoor environmental comfort, has not been comprehensively understood. This study investigated the influence of multisensory interaction on acoustic comfort, thermal comfort, visual comfort, and indoor environmental comfort with three physical indoor environmental factors, i.e., acoustic, thermal, and illumination conditions in an environmentally controlled laboratory. Three homogenous room temperatures (20, 25, and 30 degrees C) and illuminance levels were chosen (150, 500, and 1000 lx). For each of the nine configurations, four different types of sound (babble, fan, music, and water) with four sound levels (45, 55, 65, and 75 dBA) were presented for 25 s each. Sixty university students participated in all the test configurations and provided responses on their subjective comfort of discrete senses and the overall indoor environment. The results indicate that acoustic comfort increases at thermoneutrality, thermal comfort increases with a decrease in the noise level at 500 lx, and visual comfort increases with a decrease in the noise level at thermoneutrality. Indoor environmental comfort increases with a decrease in the noise level at thermoneutrality in brighter conditions. Although a specific physical indoor environmental factor has the greatest effect on the corresponding sensory comfort, other physical factors also affect the perception of subjective comfort. In steadystate thermal and illumination conditions with time-varying sound stimuli, the effect of acoustic factors was the greatest on indoor environmental comfort, followed by room temperature and illuminance. Thus, it can be concluded that the impact of acoustics on indoor environmental comfort was the greatest among the three environmental factors tested in this study.