Indoor environmental quality (IEQ), encompassing thermal comfort and indoor air quality (IAQ), plays a crucial role in occupant well-being and operational performance. Although widely studied individually, integrating thermal comfort and IAQ assessments remains limited, particularly in large-scale tropical commercial settings. Hypermarkets, characterised by spatial heterogeneity and fluctuating occupancy, present challenges that conventional HVAC systems often fail to manage effectively. This study investigates thermal comfort and IAQ variability in a hypermarket located in Gombak, Malaysia, under tropical rainforest conditions based on the Köppen–Geiger climate classification, a widely used system for classifying the world’s climates. Environmental parameters were monitored using a network of IoT-enabled sensors across five functional zones during actual operations. Thermal indices (PMV, PPD) and IAQ metrics (CO₂, TVOC, PM2.5, PM10) were analysed and benchmarked against ASHRAE 55 standards to assess spatial variations and occupant exposure. Results revealed substantial heterogeneity, with the cafeteria zone recording critical discomfort (PPD 93%, CO₂ 900 ppm, TVOC 1500 ppb) due to localised heat and insufficient ventilation. Meanwhile, the intermediate retail zone maintained near-optimal conditions (PPD 12%). Although findings are specific to this hypermarket, the integrated zone-based monitoring provides empirical insights that support the enhancement of IEQ assessment approaches in tropical commercial spaces. By characterising zone-specific thermal comfort and IAQ profiles, this study contributes valuable knowledge toward developing adaptive, occupant-centred HVAC strategies for complex retail environments in hot-humid climates.

This study assesses thermal comfort and indoor air quality (IAQ) across different zones within a hypermarket located in Gombak, Selangor, Malaysia, a region characterized by a tropical climate with high humidity and temperature. Key indicators, including Predicted Mean Vote (PMV), Percentage of People Dissatisfied (PPD), and IAQ parameters such as carbon dioxide (CO2), total volatile organic compounds (TVOC), PM2.5, and PM10, were evaluated. Significant disparities were observed between zones, with the cafeteria (Zone 5) recording the highest discomfort levels, marked by a PPD of 50%, CO2 concentrations of 900 ppm, and TVOC levels reaching 1500 ppb, primarily due to cooking activities and inadequate ventilation. In contrast, the intermediate retail zone (Zone 3) demonstrated favourable conditions, with a PPD of 12% and PMV values within the recommended range. These findings were benchmarked against ASHRAE 55 and Köppen-Geiger climate classification standards, emphasising the need for targeted improvements to enhance the thermal comfort and IAQ of the hypermarket indoor environment.