Evaluating the Impact of Sustainable Construction Practices and Design Strategies on Thermal Comfort for Energy and Cost Efficiency in Buildings

Thermal comfort has become an important concern in hot and tropical buildings due to rising temperatures, high humidity, urban heat effects and increasing dependence on mechanical cooling systems. This study evaluates how sustainable construction practices and passive design strategies can improve thermal comfort while supporting energy efficiency and cost efficiency in buildings located in hot climatic regions. The specific objectives were to identify the main problems affecting the construction of thermally comfortable indoor environments, analyse how sustainable construction methods and passive design features can improve thermal comfort and energy performance, evaluate their contribution to reducing energy costs, and propose practical strategies for achieving thermal comfort with efficient cost performance. A pragmatic, qualitative-dominant mixed-methods design was adopted, comprising a structured literature review, a questionnaire survey and semi-structured interviews. The questionnaire collected 31 responses from construction industry professionals and was analysed using the Relative Importance Index (RII) method, while eight semi-structured interviews were conducted with architects, quantity surveyors, engineers and estimators possessing local and international hot-climate project experience, analysed thematically. The findings show that humidity discomfort, temperature discomfort, indoor heat accumulation and dependence on mechanical cooling are the key thermal comfort concerns reported by respondents. Building orientation, insulation materials, wall materials and natural ventilation were identified as the major factors influencing thermal performance, while roof insulation, orientation, shading and construction materials were ranked as the most effective passive strategies. The interviews further highlighted practical measures such as cross ventilation, hollow blocks, double glazing, Low-E glass, double-skin façades, light-coloured finishes, solar systems, radiant and district cooling, and rooftop greenery, together with the central role of lifecycle costing in justifying these measures. The study concludes that thermal comfort should not be treated only as a mechanical cooling issue, but should be addressed through climate-responsive design, improved envelope performance, selective passive ventilation, sustainable material selection and lifecycle-cost-based decision making, with Quantity Surveyors positioned to support this transition through structured cost-benefit advice.