Evaluation and Analysis of Passive Energy Saving Renovation Measures for Rural Residential Buildings in Cold Regions: A Case Study in Tongchuan, China

Energy-saving renovation of rural residences is an effective means of promoting sustainable rural development. This study focuses on a single-story rural residential building located in Tongchuan City, Shaanxi Province, China (a cold region), as a case study. Retrofits were conducted on the exterior windows, roof, and exterior walls, with the addition of a sunroom. Using life cycle assessments (LCAs) and orthogonal experimental methods combined with value engineering principles, we calculated various indicators including the energy efficiency improvement rate, implied carbon emissions, proportion of implied carbon emissions, carbon footprint, carbon reduction rate, carbon payback period, and investment payback period. The impact of traditional retrofitting measures on these indicators was analyzed. The results indicate that carbon emissions from the production of building materials are a key concern among the embodied carbon emissions from the retrofits, while transportation, construction, and demolition contribute minimally. Changes in the depth of the sunroom had the most significant impact on comprehensive indicators, followed by changes to the roof. After retrofitting, the carbon reduction rate was underestimated by 9.35% to 12.02% due to embodied carbon emissions. The carbon payback period for all schemes is estimated to be between 3.27 and 4.21 years. Based on current market conditions, developing corresponding carbon economics can enhance the economic viability of the project. This approach extends the investment payback period by more than 7% while also helping to narrow the income gap between urban and rural residents to some extent. Overall, the environmental impact assessment of the alternative schemes promotes sustainable rural development and provides scientific and effective guidance for the construction of project decision-making evaluation systems and architectural designers.