Sensory influence and overall comfort: Combined effects of thermal, acoustic, and visual stimulus intensity in office environments

Most published research has studied the effects of poor indoor environmental quality (IEQ) conditions – such as elevated temperatures, excessive noise, visual glare, and poor air quality, in isolation, failing to account for the inherently multisensory nature of human perception. This study aimed to evaluate the independent, cross-modal, combined, and hierarchical effects of concurrent thermal, acoustic, and visual stimuli on subjective IEQ assessments. A simulated office (field-lab) experiment was conducted with 29 participants exposed to controlled variations in temperature (23 °C vs. 28 °C), noise (quiet vs. noisy), and lighting (glare absent vs. present) for a duration of 70 min. Data were analyzed using Cumulative Link Mixed Models (CLMM). Results showed that while fundamental sensory ratings remained largely independent, significant cross-modal interactions emerged during higher-order comfort evaluations. Stimulus potency analysis revealed that temperature exerted the strongest per-unit influence on overall comfort. While modeling overall comfort based strictly on physical parameters yielded only simple additive effects, modeling it based on subjective domain-specific comfort votes revealed significant interactions, including ceiling effects under multi-domain discomfort. These findings caution against simplistic linear IEQ models, emphasizing that future building design and assessment tools must account for non-linear integration mechanisms and context-dependent sensory dominance.