Evaluating the adaptation potential and retrofitting effectiveness of existing residential buildings in severe cold regions of China under climate change

Global climate change is intensifying extreme climate risks in the built environment, particularly in severe cold regions where summer overheating is emerging as a critical issue. Existing Retrofitting Strategies predominantly target winter heating efficiency, often overlooking summer cooling needs, resulting in potential indoor heat accumulation and increased cooling energy demand. This study utilizes the IPCC's Shared Socioeconomic Pathwaysto generate future climate projections for Harbin, China. Building Performance Simulation combined with Machine Learning is employed to evaluate energy consumption patterns in existing residential buildings under various future climate scenarios. Results reveal that while winter warming contributes to a reduction in Heating Energy Use Intensity, the frequency and severity of summer heat events significantly elevate Cooling Energy Use Intensity. Highly insulated buildings, if not supported by effective Shading Structure Length and Opening Glass Window Ratio strategies, may suffer from severe thermal discomfort during summer. SHapley Additive exPlanations analysis identifies Insulation Materials (IM) as the primary contributor to winter energy savings, but also a factor in summer heat retention. Meanwhile, SSL, Glass Type, and OGWR are found to significantly impact summer cooling efficiency and Nighttime Ventilation performance. To improve adaptive capacity, this study proposes a holistic retrofitting framework incorporating high-performance envelope materials, external shading devices, and NV. The results underscore the need to transition from winter-centric retrofitting approaches to strategies that optimize year-round energy performance and Thermal Comfort. This research provides actionable insights for architects, engineers, and policymakers in the pursuit of low-carbon, energy-efficient, and climate-resilient residential buildings.