Iranian Sustainable Building Scientific Association International Journal of Urban Management and Energy Sustainability 2538-1628 6 1 2025 01 01 Evaluation and explanation of the design indexes model of zero carbon small-scale buildings with a sustainability approachbuildings approach 271 291 732304 10.22034/ijumes.2025.732304 EN Hamid Eskandari Assistant Professor, Department of Architecture, Faculty of Technical and Engineering, Yasouj University, Yasouj, Iran 0000-0003-1385-709X Journal Article Increasing energy efficiency in buildings will significantly impact the reduction of carbon dioxide emissions, environmental damage, and operating costs. Small-scale carbon-neutral building rehabilitation with a sustainability-driven approach demonstrates that tangible, low-carbon retrofits can transform existing built environments while delivering resilient, economical, and environmentally responsible outcomes. In recent years, China has intensified efforts toward small-scale carbon-neutral building rehabilitation within a sustainability-driven framework, advancing practical retrofits, policy support, and innovative financing to decarbonize existing buildings and enhance energy resilience. The research method of this research is analytical and has been conducted in an interpretive and researcher-centered paradigm. The purpose of the research is applied and the structure of the final indexes model is developmental. The method of collecting information is documentary and library, and a questionnaire and interview have been used to conduct the research. First, using the content analysis method and inductive reasoning in developing the initial concepts and reviewing the research background, the initial theoretical framework of the research is refined, and then using the fuzzy Delphi method in the participatory decision-making approach, it is questioned and evaluated in 4 rounds using an elite panel of 19 people in the research field of expertise and finally using the results, the final framework of the indexes is presented. Findings shows, the activity areas and indices indicates that the location and site factors, such as selecting an appropriate building site and paying attention to land characteristics, are fundamental in the development of zero-carbon housing in China and results demonstrate that the integrating these indicators into policy and building codes can institutionalize sustainable practices, ensuring consistency and accountability in zero-carbon housing development. https://www.ijumes.com/article_732304_a60afeaadf31f2a598cf59f8e7ef8b60.pdf