Abstract:
Sri Lanka faces escalating electricity consumption, with buildings contributing significantly. Indoor overheating, exacerbated by inadequate sustainable design, compromises occupant comfort and amplifies energy demand in both air-conditioned and naturally ventilated buildings. This study investigates the impact of building design and occupant behaviour on thermal comfort in government office buildings in Mannar City. Case study was analysed based on orientation and height. Objective assessment and subjective assessment were collected. Thermal comfort was analysed using ASHRAE scales, PMV, and AMV. Occupant behaviour, including window opening, fan usage, and clothing adjustments, was examined. Results indicate a disparity between occupant comfort and building performance. While occupants employed adaptive strategies, the buildings exhibited thermal discomfort. The study highlights the need for integrating occupant-centered design and sustainable strategies to optimize energy efficiency and enhance occupant well-being. Future research should explore retrofitting strategies to improve overall building performance.