Sensitivity Analysis of Envelope Design for Rural Dwellings in Cold Regions of China: An Orthogonal Experiment-Based Approach

To improve the energy efficiency and indoor environmental quality of rural dwellings in China’s cold regions, this study selected a typical rural dwelling in Linyi, Shandong Province, as a case study. Integrating field measurements with parametric simulations, the Orthogonal Experimental Design method was employed to systematically evaluate the impacts of 12 envelope design parameters on building energy demand (EDtot, EDH, EDC), thermal comfort (PNTave), daylight performance (UDIave), and economic outcomes (retrofit cost and return on investment, ROI). Three sets of orthogonal experiments with varying value ranges (Case 1–3) were conducted. The results revealed that U-Window and SHGC are the most critical factors influencing energy demand and thermal comfort, while light transmittance (Trans) exerts the greatest influence on daylighting. The economic analysis demonstrated that window material is the primary determinant of retrofit costs, whereas building depth and the south window-to-wall ratio (WWR-South) significantly affect ROI. Additional range and variance analyses quantified the significance of each parameter and revealed nonlinear influence patterns. This research provides data support and decision-making references for the energy-efficient retrofit and multi-objective optimization of rural dwellings in cold regions, offering strong practical implications.