What to assess in circular buildings: key performance indicators for circular transformation

Purpose This study addresses the critical gap in evaluating building circularity by developing a comprehensive framework of key performance indicators (KPIs). While circular economy (CE) principles are increasingly emphasized in building design, their adoption is hindered by the absence of standardized and prioritized KPIs across the building lifecycle. Design/methodology/approach A two-stage research design was employed. First, a systematic meta-synthesis of literature identified micro-level KPIs. Second, industry and academic experts validated and ranked them using a two-round fuzzy Delphi method and fuzzy analytical hierarchy process. Findings The study developed the Building Circularity KPI Framework (building circularity KPIs framework [BCKPIF]), comprising 52 KPIs across six domains: material, waste, energy, water, CO2 emissions and design. Findings highlight the need to incorporate overlooked circularity aspects such as energy, water, CO2 emissions and design. BCKPIF shows a clear KPI prioritization: disassembly, refusing unnecessary new construction and material durability ranked highest overall. It also reveals prioritizations across different categories, reflecting preferred CE strategies for each category – for instance, reuse received the greatest weight for the material and waste categories. Research limitations/implications This study focuses on technical and environmental dimensions of building circularity. Economic and social aspects are excluded to allow a more focused and measurable assessment of circularity in buildings as CE focuses more narrowly on resource efficiency, material loops and system innovation. Practical implications Weighted KPIs guide practitioners in prioritizing interventions and selecting materials, technologies and design strategies. For policymakers, the results provide an evidence base for translating circular design strategies, such as reuse, modularity and deconstruction into regulatory benchmarks, procurement requirements and incentive mechanisms. The framework also supports progress toward multiple sustainable development goals. Originality/value This study advances the field by consolidating fragmented micro-level circularity KPIs into a comprehensive and weighted framework, integrating overlooked aspects such as energy, water and CO2 emissions alongside design strategies.