**2. Literature Review and Methods**

#### *2.1. Literature Review*

Compared with new buildings, energy-saving renovations of existing buildings have greater potential for reductions in carbon emissions. The existing building area exceeds 60 billion square meters in China, and more than 60 percent of buildings are without energy conservation due to low construction standards and delayed maintenance. The large-scale demolition and reconstruction of existing buildings will not only cause a great waste of resources, but also lead to environmental degradation. A previous study has shown that buildings are responsible for 40% of the primary energy consumption and lead to over 30% of global greenhouse gas emissions [23]. While new energy efficiency regulations are applied to new buildings, the existing building stock remains energetically inefficient. Therefore, energy-saving renovations to the existing buildings are considered the most scientific and effective solution to reduce total energy consumption and global greenhouse gas emissions. However, the implementation of energy-saving renovations to existing buildings in China is still relatively slow. There are so many stakeholders involved in the process of energy-saving renovations to existing buildings. As the main body regulating energy-saving renovations of existing buildings, the participation intentions of the government, energy saving service enterprises and village residents directly affect the promotion of energy-saving renovations of existing buildings. Only when the government, energy saving service enterprises and village residents have the subjective willingness to participate can energy-saving renovations of the existing buildings be effectively promoted. However, previous studies on energy-saving renovations to existing buildings mainly focused on evaluation methods [20,24–27], retrofitting influence factors [28,29], cost–benefit analysis of retrofitting [30–34], evaluations of the effectiveness of retrofitting [35,36], barriers to retrofitting [37], and technical or scheme retrofittings [38–42]. In addition, some scholars are committed to reducing existing building energy consumption through energy modernization of buildings. Richarz et al. emphasized that modernizing existing non-residential buildings can significantly contribute to declared emission reduction targets. And they presented a mixed-integer linear program that schedules measures for a building energy system including envelope and supply system [43]. Dorota presented a case study for theoretical and real effect of the school's thermal modernization and found that the real energy use reduction after the thermal modernization effect was 33% [44]. Moreover, research on buildings from other regions of Poland has shown similar possibilities of reducing energy demands by up to 64% [45–47]. Staniunas et al. made an ecological–economical assessment ¯ of multi-dwelling houses modernization and revealed that a complete replacement of windows would help decline total emissions approximately by 30% and thus greatly fulfilled initial expectations [48]. Pozo et al. analyzed the tax incentives to modernize the energy efficiency of the housing in Spain and the analysis showed that tax benefits are insufficient to promote energy efficiency, especially in those of old construction [49]. Belany et al. dealt with the possibilities the lighting retrofit and the life cycle cost analysis economic analysis

in the process of increasing the energy efficiency of buildings [50]. Furthermore, most prior studies focused on urban existing buildings, commercial buildings [27,31], historical buildings [32], educational buildings [39], and office buildings [41]. Only some of the literature discusses energy-saving renovations to existing rural residential buildings, such as the work of Hu et al. [51], Tahsidoost and Zomorodian [52], Liu et al. [53], Alev et al. [54], and Rocchi et al. [55]. However, they still focused on technical or scheme retrofitting, a cost–benefit analysis of retrofitting and evaluation methods, while ignoring the influence of stakeholders' willingness to participate in energy-saving renovations to existing rural residential buildings. In particular, energy-saving renovations of existing rural residential buildings do not have the complete policies and regulations that are implemented for urban buildings in China. Moreover, the intention of each stakeholder to participate in energy conservation transformation may only be to maximize their own interests, but it is worth investigating the best way in which to make decisions that can increase the intention of participation.
