Climate-Responsive Envelope Retrofit Strategies for Aged Residential Buildings in China Across Five Climate Zones

This study addresses the challenge of optimizing envelope retrofit strategies for aged residential buildings across China’s five distinct climate zones. A simulation-based frame work is proposed, applying a standardized Taguchi L27 experimental design to ensure direct comparability across climates. Analysis of variance (ANOVA) and effect size (partial eta squared, η2) are used to identify and quantitatively rank the sensitivity of each retrofit parameter, while interaction analysis reveals the independence or synergy between measures. Technical results are linked with discounted payback period (DPP) analysis to evaluate economic feasibility. The findings show that insulation thickness is most influential in cold climates (η2 > 0.95), whereas glazing system upgrades are dominant in warmer regions (η2 > 0.97), with parameter interactions generally insignificant. The resulting climate-responsive retrofit priority matrix offers practical guidance for region-specific design and investment decisions. This scalable and replicable method enables policymakers and practitioners to tailor low-carbon, cost-effective retrofit solutions to diverse building and climate contexts, bridging the gap between technical performance and financial viability.