*3.2. Market Information Asymmetry*

Information asymmetry is a common phenomenon in many economic fields at present. Many participants are involved in energy-saving renovations of existing rural residential buildings, with different interests and unequal amounts of renovation information. For example, when choosing energy-saving renovation technology, rural residents often do not have the ability to distinguish between good and bad, and cannot obtain reliable quality information about whether an energy-saving technology is advanced, economical or feasible. On the other hand, energy-saving service enterprises hold a great deal of relevant information on energy-saving technology, meaning that there is serious information asymmetry regarding the knowledge of energy-saving transformation technology.

In addition, information asymmetry also exists between the government and rural residents, and between the government and energy-saving service enterprises. In this case, the information-superior party will make a self-interested market choice, taking advantage of its information superiority, while the information-inferior party will be unable to make a correct judgment on the energy-saving effect of the purchased products due to the lack of information. Therefore, the information-inferior party will assume that all construction products in the construction market are of low value, and tend to choose construction products with lower prices. To maximize their own profits, the information-superior party will cater to the purchasing behavior of the information-inferior party, and produce building materials of poor quality at a low price, forcing high-quality, energy-saving building materials to withdraw from the market because their manufacturers cannot find suitable trading partners. Ultimately, the result of this is that most of the products left on the market are low-value products, which exemplifies the phenomenon of "inferior products driving out good products" [61,62].

#### *3.3. The Existing Rural Residential Buildings Have a Large Stock That Is Difficult to Transform*

Although the majority of building regulations and standards in China are targeting new and future buildings, existing buildings still constitute the largest share of the buildings stock [38]. Energy-saving construction in existing rural residential buildings is the key to building energy-saving work, and has always been a neglected but urgent problem that remains to be solved. In recent years, Chinese people's living standards have been greatly improved, accompanied by the rapid increase in building energy consumption. As one of the most important aspects of the total energy consumption in China, more attention should be paid to rural residential building energy consumption [63]. According to the Statistical Bulletin of Urban and Rural Construction in 2016, by 2016, the rural residential building area in China was about 32.32 billion square meters, accounting for 84.4% of the total area of villages and towns in China [64]. With the increase in per capita income in rural areas, the living standards of farmers have gradually improved, and the construction of rural residential buildings has reached an unprecedentedly high level. In 2019, the per capita housing construction area of rural residential buildings in China reached 48.9 m2/person, 9.1 m2 more than that of urban residents. The total number of houses has shown a continuously growing trend. As with the improvement in living quality, rural residents have also changed their energy consumption. In rural areas, people used to mainly rely on traditional biomass energy resources, such as firewood and straw [63,65,66], but these are gradually being replaced by commercial energy resources including coal, electricity, liquefied petroleum gas (LPG) and refined oil products, due to the low thermal efficiency and combustion-generated pollution of these biomass resources [63,66,67]. Thus, with the increase in the total number of rural residential buildings, the buildings' energy consumption levels are bound to rise. As a result, this building category is one of the first places in which action should be taken to reduce energy consumption and pollutant emissions [68,69].

#### **4. Subject Game Relationship**

The energy-saving renovation of the existing rural residential buildings is a complex systematic project, which involves both collective and individual interests, national interests, enterprise interests and individual interests. Firstly, as the policy maker and supervisor of energy-saving renovations of existing rural residential buildings, the government represents the national interest, and has the highest degree of participation. Secondly, the energy-saving service enterprises, as participants in contracting the energy-saving renovations of existing rural residential buildings, possess the energy-saving renovation technology for the existing rural residential buildings, and are the main representatives of the interests of all enterprises. Thirdly, the rural residents, as the owners and users of the existing rural residential buildings, can benefit from the energy-saving renovations to the existing rural residential buildings, but, at the same time, face an increased cost of living, which affects their personal interests. All three parties are the main participants in the energy-saving renovations of existing rural residential buildings, and this study also focuses on their evolutionary game relationships. As for other auxiliary participants, such as banks, financial institutions, the environmentalists, etc., they have not directly participated in energy-saving renovation of existing rural residential buildings. Their suggestions or financial support can promote energy-saving renovation of existing rural residential buildings, but compared with the government and rural residents as funders and energysaving service enterprises as designers and constructors, their impact is less. For example, suppose the environmentalists propose that energy-saving renovation of existing rural residential buildings is beneficial to protecting the ecological environment. However, if the government and rural residents do not realize or support it, their proposal will not be effectively solved. On the contrary, if the government and the rural residents are also aware of the importance of energy-saving renovation of existing rural residential buildings, and actively respond to the environmentalists' proposals, but the environmentalists are not involved in the related issues such as who will supervise, who will renovate, and who will bear the cost during the promotion process. These auxiliary participants will be a new field for our research team to further study in the future, but this study will focuses on the main participants.

#### *4.1. The Government*

In the process of energy-saving renovations of existing rural residential buildings, the government, as the policy maker, shoulders the task of supervision, management and publicity, and regulates the behaviors of other participants by implementing economic incentive policies and administrative supervision, which mainly focuses on the social and environmental benefits brought by energy-saving renovations of existing rural residential buildings. Therefore, as a special participant, the government will pursue the long-term social and environmental benefits of energy-saving renovation, as well as the improvement in people's living standards and social stability.
