Investigating thermal comfort indices in relation to clothing insulation value: a survey of an outdoor space in Tehran, Iran

Abstract: With the increasing impacts of climate change, there is a need for more accurate assessments of thermal comfort. This study addresses the limitations of current thermal indices in accommodating variations in clothing insulation, which is a critical behavioral adaptation influencing human thermal comfort. Many existing indices, such as Physiologically Equivalent Temperature (PET) and Standard Effective Temperature (SET*), rely on fixed clothing insulation values that may not accurately represent real-world conditions due to environmental, cultural, and behavioral variability. In contrast, some indices like the modified Physiologically Equivalent Temperature (mPET) and the Universal Thermal Climate Index (UTCI) allow for adjustable clothing insulation; however, UTCI's fixed values can be insufficient in regions with distinctive clothing practices, impacting its accuracy. This study evaluates the effectiveness of thermal comfort indices by conducting a field survey and questionnaire, collecting a total of 838 data sets. The analysis employs various methods, including sensitivity and specificity analysis, principal component analysis (PCA), alluvial diagrams, and polynomial charts. Findings highlight the limitations of fixed insulation values in indices such as PET and SET*, while emphasizing mPET's superior accuracy in predicting outdoor thermal comfort. PCA identified clothing insulation (Icl) as a significant personal factor affecting thermal comfort across diverse environments. This research reveals differing correlation coefficients at higher insulation levels (1.11-1.26 clo and 1.26-1.56 clo), with SET* exhibiting substantial variability (0.33) compared to mPET, which demonstrated the least variability (0.46). These results underscore the need to revise existing thermal comfort indices to incorporate more dynamic and context-sensitive insulation values for improved thermal predictions

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch
• Notes: Sustainable cities and society. - 118 (2025) , 105993, ISSN: 2210-6707

Contributors, Places and Time

• Event: Veröffentlichung
• (where): Freiburg
• (who): Universität
• (when): 2024
• Creator: Zafarmandi, Sevil ; Matzarakis, Andreas

Further information

• DOI: 10.1016/j.scs.2024.105993
• URN: urn:nbn:de:bsz:25-freidok-2592852
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 15.08.2025, 7:37 AM CEST