## 1 Introduction  
The building and construction sector is the largest energy consumer and greenhouse gas emitter, responsible for 39% of global energy-related carbon emissions [1]. In the context of growing global environmental awareness and the implementation of policies to reduce energy consumption and emissions, the significance of energy-saving renovation in the building sector is increasing. As the largest energy consumer and the primary source of carbon dioxide emissions, China plays a pivotal role in the global effort to combat climate change. As China experiences an increase in building energy consumption driven by rising living standards and economic expansion, the importance of the building sector will only grow. This trend poses a considerable challenge to achieving China's carbon peaking and neutrality objectives. China's 14 th National Five-Year Plan places significant emphasis on the modernization of aging residential areas to enhance living conditions, promote development, and improve local governance. The Plan's objectives are twofold: first, to renovate more than 350 million square meters of existing buildings by 2025 [2]; and second, to increase energy efficiency while reducing energy consumption and emissions, with a particular focus on regions experiencing seasonal temperature extremes [3]. However, applying retrofitting strategies to existing constructions necessitates the resolution of numerous challenges while offering prospects for advancement, including climate change, financial limitations, changes in human behavior, shifts in governmental policy, and disruptions to operations [4]. Current approaches in China to building retrofitting frequently employ rigorous energy-saving measures, such as those outlined in the Passivhaus standard [5] or the local nearly zero-energy building code [6], which prioritize insulation and, in the case of Passivhaus, emphasize the airtightness of the building envelope, particularly in extremely cold climate zones. A considerable body of research has demonstrated the efficacy of these high-performance energy building standards, indicating a significant reduction in energy usage. Current building retrofitting efforts aim to minimize heat losses through both opaque and transparent components of the building envelope, as well as to eradicate thermal bridges and ensure minimal air leakage. However, studies have identified potential negative impacts, such as the risk of indoor overheating during summer and increased cooling demands due to the building's airtightness and heavy insulation [7]. Furthermore, difficulties in meeting cooling energy demands during energy-saving retrofits have been observed, even in some severe cold climates [8; 9]. Given future climate change and its associated environmental consequences [10], the carbon emissions generated by insulation materials and aluminum used for external shading systems must also be considered. While aluminum shading systems are increasingly popular due to their relatively low cost and adaptability to various forms, their production contributes significantly to carbon emissions [11]. Consequently, implementing excessively stringent energy-saving design standards without holistic evaluation may inadvertently exacerbate climate change [12]. The primary challenge in optimizing building retrofits is selecting and implementing the most effective technologies to enhance energy performance, reduce carbon emissions and environmental impact, and ensure acceptable initial investment and payback periods within realistic constraints. Therefore, selecting appropriate energy-saving renovation strategies is a multi-objective decision-making task, which requires identifying the most effective balance between multiple performance indicators. Simulation software has been frequently employed with optimization algorithms to automate the optimization process [13].