Cost-effective and low-carbon solutions for holistic rural building renovation in severe cold climate

Rural houses in China's severe cold climate face pressing challenges due to harsh winter conditions, outdated construction, and inefficient energy systems, leading to high energy costs and poor indoor air quality. This study proposed a holistic renovation approach, incorporating key renovation measures across building envelope upgrade, ventilation improvement, and distributed energy system application. Simulation-based multi-objective optimization was utilized to explore optimal solutions, which balanced two key objectives: minimizing both net present value of life cycle cost and CO2 emissions of energy use. Future scenarios assessed the sensitivity of optimal solutions to factor changes regarding thermal comfort, economic, and energy environmental impacts. Results indicate that a biomass pellet boiler achieves the greatest emission reduction, followed by PV-combined air-to-water heat pump, natural gas heater, PV-combined electric boiler and electric boiler, lowering CO2 emissions from 109.4 kg CO2/m2 to 10.7-53.4 kg CO2/m2. The holistic renovation reduces emissions more efficiently than only focusing on envelope upgrades. Cases with heat pump and biomass pellet boiler even show lower life cycle cost than standard envelope renovation. These findings offer valuable insights for decisionmakers, supporting the adoption of clean energy solutions in rural areas facing extreme climatic conditions.