Assessing the Heat Vulnerability Index (HVI) in Klang Valley Using Principal Component Analysis (PCA) and an Equal-Weighted Approach

Urbanization has led to more than 50% of the global population residing in urban areas, contributing to significant modifications in the urban climate that exacerbate the adverse effects of climate change, particularly on human health. This study aims to assess the Heat Vulnerability Index (HVI) in the Klang Valley, Malaysia, using Principal Component Analysis (PCA) and Equal-Weighted Index (EWI). It further compares both methods to determine which more effectively reflects the region’s environmental and socio-economic context. Focusing on land surface temperature as an exposure, other sensitivity and adaptive variables were triangulated where the heat vulnerability index is developed. The findings show the Klang valley’s regions are of varying degrees of vulnerability to heat stress, with the most affected cities being Kuala Lumpur and Petaling due to exposure-sensitivity and adaptive capacity factors. As can be seen, HVI_PCA covers 7.06% for Very Low, 12.87% for Low, 54.82% for Moderate, 14.99% for High, and 10.26% for Very High vulnerabilities while HVI_EWI represents Very Low at 6.62%, Low at 51.29%, Moderate at 26.86, High at 15.22% and Very High at 0.02%. These differences underscore the importance of methodological choice where PCA supports empirical robustness based on data driven, while EWI is suitable when expert consensus is lacking, or when simplicity and broad stakeholder buy-in are needed. Recommendations include maximising indicator representa-tiveness for accurate assessments and resilient urban planning against heat-related stressors. The study could serve as baseline HVI of the study area so the pre-emptive techniques could be developed to mitigate the extreme heat condition.