Research on NSGA-II-Based Low-Carbon Retrofit of Rural Residential Building Envelope Structures in Low-Latitude, High-Altitude, Warm-Climate Regions

Rural residential structures account for a substantial share of carbon emissions within the construction industry. Enhancing building envelopes can diminish structural carbon emissions, thereby facilitating the attainment of “dual carbon” objectives. Current algorithm-driven research on the low-carbon retrofitting of residential building envelopes generally neglects temperate regions in low-latitude plateaus, often misses embodied carbon, and utilizes rather limited methodologies for issue identification. This study focuses on rural dwellings in Lijiang, utilizing a cross-validation method that incorporates sensitivity analysis, infrared thermal imaging, and energy efficiency criteria to systematically identify vulnerable regions in the building envelope. Consequently, critical issues are converted into optimization variables for the NSGA-II method, aiming to minimize both embodied carbon and operational energy usage. BAPV is concurrently implemented to partially mitigate renovation expenses. A weighted summation approach delineates stakeholder preferences, resulting in three optimum options. The findings reveal that all three methods correspond to their unique preferences, illustrating distinct trade-offs among energy efficiency, carbon reduction, and economic feasibility. The government-oriented approach attained an energy saving rate (ESR) of 45.11%, a life cycle carbon reduction (LCCR) of 1215.76 kgCO2/m2, and a dynamic payback period (DPP) of 3.65 years. The architect-oriented approach realized the highest energy savings and carbon reduction (45.41%, 1218.96 kgCO2/m2), with a payback period of 3.99 years. The villager-oriented approach emphasized economic viability, achieving an energy savings rate of 41.55%, a carbon reduction of 1149.46 kgCO2/m2, and the shortest payback period of 2.87 years. This study provides an optimization process and reference parameters for building envelopes in a low-carbon design for residential buildings in temperate regions of low-latitude plateaus.