## 5 Discussion  
This study combines qualitative and quantitative analyses to reveal the mechanism of the interaction of energy-saving technologies, socio-economics, policies and regulations, and market demand factors affecting the comprehensive benefits of residential building renovation by constructing the SD model of the comprehensive benefits generated by the renovation of existing residential buildings and the results of the simulation. Furthermore, a discussion on the limitations and comprehensive benefits of the retrofit and factors affecting the retrofit is necessary.  
In analyzing and selecting retrofit strategies for one or more buildings, the main question is how to define the best alternatives. Researchers and professionals have developed several methods to address this issue and aid decision-making [50,51]. Retrofitting the urban-scale models for building type, building age, and other high dimensions increases the difficulty in selecting retrofitting strategies. However, most researchers choose commonly used strategies without considering this.  
A change in a certain aspect of the input can enhance the benefits of residential building renovation, but it cannot completely and synergistically produce an equal growth in energy consumption, environment, and economic tripartite benefits, and it cannot solely improve energy consumption at the expense of the economic benefits. Generally, cost benefits constrain energy benefits and environmental benefits. It is noted that the choice of criteria or indicators can influence the results of the benefits and, consequently, the process of selection of retrofit strategies. How to choose the fitting energy-saving technologies and standards to maximize the balance of benefits is an issue to be further explored in the future.  
The results of different scenarios simulated by the SD model show that the increase in the rate of technological progress has the greatest impact on the comprehensive benefits of the retrofit of existing residential buildings and plays a central role in the implementation of the retrofit of old neighborhoods. In recent years, several studies have addressed the  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & & & & & & & \\ \hline \multicolumn{6}{c}{Scenario} \\ Year & S1 & S2 & S3 & S4 & S5 & S6 & S7 \\ \hline  
\hline \hline \end{tabular}
\end{table}
Table 7: _Cont._concept of Building Information Modeling (BIM), renewable energy, and so on. These emerging technologies can enhance the benefits of retrofitting [52; 53].  
The simulation of market factors found that the willingness of enterprises to participate in comparison to the promotion of energy-saving products to bring more obvious comprehensive benefits and the marketization of building energy-saving renovation shows an inevitable trend to promote the development of the renovation project in the future, which requires the synergism of technology, policy, and market demand. The reduction in incremental cost of the renovation project undoubtedly increases the enterprise's willingness to participate, providing intrinsic motivation, and the need to renovate the scale of market demand, also increases, and the government incentives and policy regulations also simultaneously play a role in this process.  
Furthermore, financial limitations should also be considered, as some retrofit strategies may require a high initial investment or have a long payback period [54]. The retrofitting program will face large challenges. The increase in the level of policy at the later stage is reflected more in the improvement in the type of economic incentives, the degree of building energy efficiency tax breaks introduced by the government, the strength of the financial subsidies, the support of the enterprise credit approval, and the priority of the land grant policy.