Climate change and rapid urbanization have rendered cold regions critical battlegrounds for global carbon neutrality efforts, where the built environment accounts for a disproportionately high share of energy-related emissions. In such contexts, smart neighborhood renewal—combining energy-efficient retrofitting, digitalized infrastructure, and sustainable behavior incentives—emerges as a promising yet underexplored pathway to reduce building carbon footprints. However, the interplay between technological innovations, spatial characteristics of communities, and occupant behaviors in cold climates remains inadequately understood, particularly in balancing short-term costs and long-term sustainability. This study addresses this gap by examining how integrated smart renewal strategies can be designed and prioritized to optimize carbon mitigation in cold-region residential areas, with Harbin, a typical city in China’s severe cold zone, as a case study. The research adopts a mixed-methods framework to bridge technical energy analyses, spatial pattern assessments, and socio-behavioral investigations, thereby capturing multi-dimensional drivers of emission reduction. Data collection encompasses historical energy consumption archives, geospatial mapping of neighborhood layouts, policy documents on urban renewal, and surveys of resident engagement in energy-saving practices. Analytical processes focus on three thematic clusters: (1) Evaluating the carbon reduction potential of smart heating systems, renewable energy integration, and building envelope upgrades under extreme cold conditions; (2) Uncovering how urban morphology—such as building density, orientation, and green infrastructure—modulates the effectiveness of retrofitting measures; (3) Identifying behavioral barriers and enablers for residents’ adoption of smart energy management tools. The findings reveal that smart renewal initiatives achieve optimal emission reductions when aligned with the specific climatic, spatial, and socio-economic contexts of neighborhoods. Densely clustered low-rise communities, for instance, exhibit amplified benefits from collective solar energy sharing and windbreak-enhanced thermal performance, while sprawling high-rise districts require decentralized solutions like adaptive heating zoning and AI-driven demand forecasting. Crucially, the study underscores the dual role of occupant behavior: While smart meters and real-time feedback interfaces significantly enhance energy-conscious actions, cultural preferences for high indoor temperatures and distrust of automated systems pose implementation challenges. Furthermore, spatial inequities emerge as a critical concern, as aging neighborhoods with limited fiscal and technical capacities risk being marginalized in the smart renewal transition. The analysis proposes a tiered intervention framework that categorizes communities based on their emission profiles, infrastructural readiness, and resident participation thresholds, advocating for phased investments in foundational energy-saving measures before deploying capital-intensive smart technologies. Policy recommendations emphasize the need for adaptive governance models that synchronize municipal carbon targets with neighborhood-scale pilot projects, cross-sector data-sharing platforms, and financial mechanisms to alleviate cost burdens on vulnerable households. Theoretically, this research advances the discourse on sustainable urban transitions by conceptualizing cold-region smart renewal as a socio-technical system requiring synchronized hardware upgrades, software optimization, and resident engagement. Methodologically, it demonstrates how transdisciplinary approaches can disentangle complex interactions between physical infrastructures and social practices in carbon governance. Future research directions include longitudinal studies to track behavioral evolution post-renewal and comparative analyses across diverse cold-climate cities to refine contextual adaptability. By situating technical solutions within the realities of spatial diversity and human agency, this study offers a holistic roadmap for decarbonizing residential areas in cold regions while addressing equity and feasibility concerns inherent in urban sustainability transformations. keywords:Smart community retrofitting, Cold region, Carbon emission, Renewable energy