Comparative assessment of LEED, BREEAM, and GSAS in achieving environmental impact reduction: A performance based analysis

Green building certification systems play a crucial role in promoting sustainable construction practices and minimizing environmental impacts. Among the most recognized frameworks worldwide are Leadership in Energy and Environmental Design (LEED), the Building Research Establishment Environmental Assessment Method (BREEAM), and the Global Sustainability Assessment System (GSAS). Each system offers a systematic framework for sustainability, techniques, weighting criteria, and efficacy in decreasing the environmental footprint. This research compares the three rating systems by examining key parameters that include energy efficiency, reduction of carbon emissions, water conservation, material selection, and the quality of the indoor environment. Furthermore, certification guidelines, case studies, and performance data were analysed to evaluate each certification's strengths, limitations, and effects in the real world. These findings indicate that GSAS achieved the highest total sustainability score of 42.0, using multi-criteria decision analysis (MCDA), followed by LEED and BREEAM, with 14.4 and 11.9 respectively. The results highlight which rating system delivers stronger sustainability outcomes, assisting developers, policymakers, and practitioners in identifying the most appropriate framework for their projects. This study ensures that sustainability assessments are accurate, comparable, and successful in guiding construction and urban development towards greener, sustainable approaches.