Energy performance of renovated green facades in rural China: Multi-climate comparative analysis

With the acceleration of urbanization and the continuous expansion of building areas in China, rural buildings, which account for 50 % of the total residential building area in the country, exhibit serious thermal deficiencies due to the general lack of thermal insulation systems. In this study, the reliability of the DesignBuilder simulation is verified through field experiments (July-August 2024) with strict error thresholds (MBE ≤±5 %, CVRMSE ≤15 %). According to the Chinese thermal design code for civil building (GB 50176–2016), the energy-saving potential of green façade retrofitting for rural buildings in different climate zones was systematically evaluated through simulation studies in seven cities distributed across five climate zones. The experimental results show that the electricity consumption of the reference room is 1.84 times higher than that of the vertical greenery room, and the indirect green façade achieves an energy-saving effect of 45.75 %. Comparative analysis of the simulation results shows that there are apparent geographical differences in the retrofitting effect: Guangzhou in the hot summer and warm winter region has the best energy-saving effect, with an energy-saving rate of 16.04 %, while Urumqi in the severe cold region has the worst energy saving effect, with only 2.54 %, which is a stark contrast to the other. ● Field experiments quantified energy-saving effects of green facade retrofits in Chinese rural buildings. ● Verified DesignBuilder's reliability by comparing field data with simulations (MBE≤±5%, CVRMSE≤15%). ● Simulated retrofit performance across seven cities revealed region-specific energy-saving effect.