Homeowners’ Participation in Energy Efﬁcient Renovation Projects in China’s Northern Heating Region

: In China’s government-led energy efﬁcient renovation of residential buildings, homeowners’ participation refers to their involvement and engagement throughout the process. Lacking homeowners’ participation has brought difﬁculties in the execution and ﬁnancing of the projects. This paper explores the current situation of homeowners’ participation and provides suggestions for optimization from three perspectives: the steps and procedures of the participation process, the composition of the working group responsible for contacting the homeowners, and the contents to be discussed during the process. The semi-structured interview and questionnaire results show that homeowners’ participation is not adequate, and the current arrangement deviates from their expectations. Although most homeowners are positive towards government-led renovation and are enthusiastic about being involved, the process setup is not well-designed to let them fully participate. Moreover, their expectations and preferences are related to several factors. It can be concluded that relevant laws and regulations should be introduced to provide a basis for solving problems at the executive level, and homeowner associations should be established to serve as a channel of communication between homeowners and the working group. Designing targeted renovation and participation strategy is a necessity to minimize the communication efforts.


Introduction
Household energy consumption accounts for 80% of the whole building sector in China [1]. Due to the loose energy efficiency standards in the past, the energy performance of the large existing housing stock in China is much more unsatisfactory than that of the new buildings. Energy consumption per building in China is 2-3 times higher than that of developed countries with similar climatic conditions, and buildings are less comfortable due to poor thermal performance and insufficient insulation [2]. To step towards a more sustainable building stock, China's central and local governments have been promoting energy efficient renovation of district-heated apartment buildings in urban areas. The major renovation of apartment buildings must be undertaken collectively. Thus, it has been implemented through a "top-down" model, in which central and local governments take charge of renovation projects and make the majority of the investment [3].
In government-led renovation projects in China, "participation" is used to describe homeowners' involvement and engagement in the planning, decision-making, operating, and managing process. There is no consistent definition of participation at the policy level in China; nevertheless, it generally refers to the interaction between homeowners and the "responsible agency", which is usually a working group commissioned by the local government. The working group should mobilize the homeowners to undertake the renovation, provide them with adequate and accurate information, and collect their opinions and feedback to determine and adjust the renovation plan. Meanwhile, the homeowners are expected to cooperate with the government. They will be asked if they However, compared to making minor renovations on their initiative, homeowners are less willing to cooperate in projects involving the coordination of multiple residents [20]. They consider the apartment unit to be their home instead of the whole building [21]. Furthermore, being unable to broker an agreement with all homeowners makes it difficult to arrange financing matters [20]. Some are unwilling to pay because they believe other stakeholders should be responsible for investing [5]. Others may find the investment to be financially unattractive [22]. Correspondingly, the difficulty of gathering sufficient expenditure and implementing renovation measures is increased.

Homeowners' Participation in Apartment Building Renovation in Other Countries and Regions
Renovation of apartment buildings is usually carried out under the cooperation of multiple actors, such as energy-providing companies, banks, construction engineering and supplying companies, municipalities, associations, policy implementing authorities and agencies, and policy-making authorities [23]. In countries and regions where apartment buildings are highly privatized, homeowners can be involved to different degrees, from being informed to being part of decision-making [24].
Launching the renovation process depends on the general approval of all the homeowners. Thus, a few active "saboteurs" who are against the renovation can successfully cause other homeowners' doubt, and it takes a long time for experts or fellow homeowners to convince and persuade them [21]. To obviate the obvious difficulty, in Lithuania, the local authorities will present homeowners with theoretic evaluations that are far from the actual situation, making them overestimate the effect of the renovation [25]. In Moscow, municipal administrations tend to conceal the actual technical state of the building to avoid the expenditure of resettling the residents [26]. On the one hand, these solutions intensified the homeowners' distrust of the local authority; on the other hand, they imposed risk to the homeowners.
Lacking homeowners' participation in renovation projects has correspondingly increased the difficulty of gathering sufficient expenditure and implementing renovation projects. For instance, in the Moscow housing program, the residents were not involved in financing, and thus all the costs of implemented building renovations had to be covered by the budget of the City of Moscow [27]. Chileshe [28] concluded that lacking consultation between the service providers and contractors with the residents would be the most significant barrier affecting home renovation in the future.
Some studies suggested that homeowners should be involved at specific times throughout the process. Mirakyan and De Guio [29] developed a generic integrated energy planning procedure of cities and territories in which the planning activities are divided into four main phases: preparation and orientation, detailed analysis, prioritization and decision, and implementation and monitoring. In their opinion, the general public can be involved in the third phase, prioritization and decision, during which workshops should be organized for multiple interested stakeholders to compare options and select strategies. Pedersen [30] suggested that residents be considered partners in renovation decisions, and measures that impact homes-such as overall intention, reasons and planning, and craftsmen's activities-should be explained to and supported by the residents.
Due to homeowners' bounded rationality, their reactions can differ when different actors deliver the same information. Moreover, because of the uniqueness and uncertainty of projects, the outcome of non-standardized customer interaction will be more dependent on the service provider's personnel. Thus, actors who deliver relevant information to homeowners may directly affect the implementation of renovation projects. Interaction between actors creates an informational environment in which information is not precise and objective [23], making residents' decisions deviate from theoretical models. Högberg [31] suggested that the differences between real estate companies and managers should be considered in the policymaking of renovation, for different types of people have different attitudes and mindsets. Holm [32] argued that home renovation should belong to the service industry; thus, customer satisfaction is necessary. Paiho [27] mentioned that the investors of renovation projects could partner with local authorities to keep the residents informed, which may help overcome the obstacle caused by apartment owners' distrust.

Steps and Procedures of Renovation Projects
Unsure about or disagree with the renovation procedure is a significant reason for Chinese homeowners to be reluctant to renovate [33]. The only instruction given as a reference for arranging work about homeowners' participation is in Chapter 3: Communicate with Residents, Guideline for Energy Efficient Renovation in Residential Buildings [8] issued by MOHURD (the Ministry of Housing and Urban-Rural Development) (see Figure 1).
According to the instruction, when the government makes renovation decisions, a working group should be formed to inform the homeowners. Working group should first be trained, and take responsibility for several actions, e.g., investigate homeowners' profile, including their household composition, living condition, and attitude towards renovation; invite homeowners to discuss the renovation plan; sign agreements with homeowners and charge them; educate homeowners to use and maintain new energy efficient facilities. The communication and negotiation should go several rounds to ensure that homeowners are fully informed. This guideline does not specify which agency should form the working group and arrange homeowners' participation.
In this guideline, it is suggested that a project can be executed if 75% of homeowners agree on the program and sign the agreement. However, the instruction is not mandatory, and to our knowledge, there are no statistics about whether the process is executed in real situations.

Composition of Working Group
In China, the resolution of residential community management affairs mainly relies on the interaction among neighborhood committees, property management companies, homeowners' committees, and individual homeowners [34]; an active and efficient responsibility mechanism for homeowners' participation has not been established. Homeowner associations only emerged very recently in China and have not been widely promoted or standardized-even in many big cities, it has only been established in around 20% of residential communities by 2014 [35], and there are significant discrepancies in its ability and effectiveness to deal with problems [36]. If a conflict or dispute occurs, the neighborhood committee would usually become the critical coordinator and mediator, and deliberation has been the primary instrumental tool for conflict resolution [37]. However, neighborhood committees' role is limited to daily affairs; they are not empowered to make crucial decisions and manage essential issues.
Some domestic studies have found that, apart from homeowners, some stakeholders can play a role to communicate with homeowners in the governance of residential communities, such as municipal governments, urban planning bureaus, legal affair offices, subdistrict offices (Chinese: 街道办事处), and non-governmental organizations [38,39]. Nevertheless, it is not specified which actors might be involved in the working group and be responsible for arranging homeowners' participation in energy efficient renovation. In other words, to our knowledge, we do not know who is responsible for contacting the homeowners in actual energy efficient renovation projects. It is also unknown whether they can deliver necessary information efficiently to the homeowners.

Contents of the Discussion
The contents of the discussion between homeowners and the working group members are also important. The MOHURD guideline suggested that the following content should be clarified in the agreement: renovation measures, charges and fees, construction period and time, rights and obligations, removal plan of illegal structure, and other necessary matters.

•
Renovation measures describe the technique measures carried out in the project, generally including the construction of doors and windows, external walls, roofs, and heat supply system. It will directly influence how the project will be carried out and what outcome shall be expected.

•
Charges and fees clarify whether homeowners need to pay for the renovation, and if so, what is the financial plan. Currently, in most cases, homeowners do not pay for the renovation. • Construction period and time will determine the extent to which homeowners' daily life is affected. Compared to the construction of newly built buildings, the renovation project's construction work is carried out with more constraints. For example, the construction period is shorter, the site's conditions are often more complicated, and the construction work is more dependent on the weather. • It is not specified in the guideline that what rights and obligations homeowners have. During the participation process, the rights and obligations of both sides should be discussed and clarified. • Many target buildings have poor conditions, and residents would build some illegal structures to improve their original homes' living functions. These structures include canopies, storage rooms, and balconies. In some cases, residents have been using their homes for small businesses and have added illegal neon lights or signboards. The removal plan of the illegal structure must be discussed; otherwise, it may cause conflicts if these structures need to be demolished during the renovation.

Methodology
The data collection process of the paper is organized as follows. Interview and questionnaire surveys were used in this study. Firstly, interviews were conducted to gather detailed information on the actual implementation of renovation projects. Some interviewees were interviewed individually, and others are from three representative renovation cases in the Northern Heating Region. A questionnaire was designed and disseminated by both hard copies and an online survey website based on the interview findings (see Appendices A and B).

Semi-Structured Interview
A total of 47 participants were interviewed (see Table 1). The interview was semistructured. Interviewees were encouraged to share all their opinions towards renovation projects. Members of construction management teams who are responsible for contract designing and implementing.
Neighborhood committee member 7 Members of neighborhood committees from three residential communities (2 in Tianjin/1 in Beijing) that had been renovated.
Property management company employee 3 Staff of property management companies from three residential communities (2 in Tianjin/1 in Beijing) that had been renovated.
Homeowner association member 12 Members of homeowner associations from three residential communities (2 in Tianjin/1 in Beijing), representative of homeowners who have undertaken renovation.
Three renovated residential communities in Tianjin and Beijing were selected as representative cases (see Figure 2). Neighborhood committee members, property management company employees, and homeowner association members from these three cases were interviewed, engaging 22 interviewees. Tianjin and Beijing are among the leading cities of energy efficient renovation. All three cases were renovated under the local government-led model. The renovation of residential communities is usually not carried out to all buildings together. Therefore, homeowners interviewed are either from renovated or un-renovated buildings. To avoid biases related to the interviewee selection, we selected three residential communities with different features, such as the scale of the community, the total floor of the buildings, the year of building, and the adopted renovation measures. The detailed information of all three cases is presented in Table 2.  A further 25 interviewees were practitioners who took part in renovation projects, such as government employees, construction managers, architects, energy company employees, and researchers who specialized in relevant research domains. The access to these interviewees was achieved through social networks, as they were asked to suggest potential participants when the interview finished.
Interviewees were asked to introduce some basic information about themselves initially, e.g., their personal opinions towards energy efficient renovation. The interview's body mainly includes the following topics: steps and procedures of renovation, commonly applied technical measures, communication with homeowners, and negotiation with homeowners. They are also encouraged to share opinions on other aspects of the renovation. The knowledge obtained by interviews will be used for questionnaire design.

Questionnaire Survey
A total of 500 hard copies were sent to homeowners directly by person in several key areas for energy efficient renovation in the Northern Heating Region, namely Beijing municipality, Tianjin municipality, Hebei province, and Heilongjiang province. Overall, 185 valid questionnaires were collected through this approach. Meanwhile, 294 valid responses were collected from unpaid anonymous respondents in all the provinces and municipalities in the Northern Heating Region through an online survey website, "wenjuanxing (Chinese: 问卷星)". Thus, the total amount of sample in this study was N = 479.
In the questionnaire, respondents were asked to assume that they face an actual government-led energy efficient renovation in their apartment. They needed to indicate whether they would like to undertake the renovation and answer questions about their preferences and expectations regarding the composition of the working group and the content discussed during the participation process. Respondents also needed to indicate whether their apartment had been renovated. Those who had undertaken renovation will need to finish another set of questions about details of their experiences. The order of options in the body of the questionnaire was randomly displayed. By the end of the survey, respondents would need to provide their demographic profiles. They are also encouraged to provide any further concerns in a free comment space. Table 3 gives a summary of the socio-demographic characteristics and buildings features of the sample. We collected respondents' gender, age, occupation status, highest education level, and annual household income to investigate how these factors are related to homeowners' willingness to participate. Since the target buildings of energy efficient renovation are similar in many building conditions, such as building age, location, and energy performance, we only collected the following features: the total floor of the building and the floor area of the unit. Apart from the above-mentioned factors, a large body of research has identified the influence of behavioral factors on homeowners' energy-related decisions. These factors can give a new perspective to analyze the reasons for homeowners to make decisions [40]. Existing applied behavioral research on energy efficiency mainly focuses on individual homeowners who can take the initiative to renovate their own homes. It remains unknown if homeowners' decisions to participate in government-led renovation projects are also subject to these factors. Thus, behavioral factors that seem applicable in the government-led renovation were included in the questionnaire.
As shown in Table 4, it can be concluded that respondents are not very satisfied with their indoor comfort level and do not reflect a great interest in general environmental protection issues. Meanwhile, the approval level for energy efficient renovation is relatively high. Most respondents have at least some knowledge about the renovation. About half of the respondents thought the renovation should be promoted and encouraged, indicating a very positive attitude. Furthermore, 112 respondents finished Section 4 of the questionnaire, indicating they had undertaken government-led energy efficient renovation.

Steps and Procedures
Firstly, interviewees were asked to provide comments on the steps and procedures of renovation after reviewing the instruction for homeowners' participation from Chapter 3: Communicate with Residents, MOHURD Guideline (see Figure 3). It demonstrated an ideal procedure for how homeowners can be involved in the renovation project's whole process.
It was generally agreed that the given instruction is reasonable. However, interviewees suggested several aspects that could be improved. Based on the suggestions above and other opinions from the interviewees, an improved workflow is proposed in Figure 3.
The main idea is to create opportunities for homeowners to be actively involved in the process. In the investigation step, after informing homeowners about the upcoming work, the working group should organize events to give a detailed explanation about the renovation measures and technique terms to homeowners, such as seminars of pilot project visit. It may also be helpful if the working group can present several renovation alternatives to homeowners with different costs and outcomes and formulating guidelines for homeowners with clear and simple contents. After investigating each household's exact condition, followed by several rounds of discussion and feedback, the working group should let homeowners confirm the proposal before starting to charge fees and sign the agreement.
Another part of improvement is the finalization step, during which the working group should teach homeowners to use the new energy-saving facilities. According to interviewees' opinion, it should start with confirming the successful adoption of all the renovation measures to ensure effectiveness and safety. Homeowners' ability to properly use the new facilities is critical for the renovation effect, for some of the facilities can only work when homeowners' energy use behaviors are adapted. Thus, a follow-up survey is essential, making it possible to observe homeowners' behavior change after renovation.

Composition of Working Group
Through the interviews, we concluded that the working group is mainly composed of government employees, neighborhood committee members, energy company employees, and property management company employees. Hence, these four categories formed the options in the questionnaire as we asked who had been in charge of the communication.
In most cases, government employees are the leader of the working group. Most of the practitioners and researchers believed that homeowners trust them more than people from other agencies. They also believed that neighborhood committee members are more familiar with homeowners' daily lives, making them more suitable for mediating contradictions during the negotiation process. In projects involving the renovation of heating systems, such as heat metering and replacing heat pipes, energy company employees are responsible for explaining some necessary details, including how the construction will occur and how to calculate the heating cost after renovation. Property management company employees are often responsible for charging fees and taking on other specific works.

Contents to Be Discussed
Based on the instructions in the MOHURD Guideline and interviewees' suggestions, the following contents were identified to be discussed during the communication with homeowners: renovation measures, financial plan, time plan, construction plan, maintenance methods, contractor, construction team, and material. Some are already included in the MOHURD Guideline or are adjusted from items in the Guideline; some others are proposed by the interviewees. A comparison of these items is shown in Table 5. Table 5. Content to be discussed, comparing instructions in the MOHURD Guideline and interview results. "Renovation measures" describes the combination of technical measures listed by the MOHURD Guideline, which is obviously necessary to be discussed. "Charges and fees" is adjusted into "financial plan", which describes the extended negotiation about the financial issues, such as whether the cost can be paid by installments, and how the residents in the same apartment could split the bill. "Construction period and time" and "removal plan" can be restructured into "time plan" and "construction plan". Apart from the above, interviewees suggested some new items: "maintenance methods", "contractor", "construction team", and "material". "Material" specifies how the renovation will be carried out. "Financial plan", "contractor" and "construction team" are about the arrangement of funding and staffing. "Maintenance methods" includes two aspects: how professional workers maintain the new energy-saving facilities and how homeowners can use them properly. Interviewees suggested removing "rights and obligations", because the rights and obligations of both sides should already be clearly defined at the policy level. If these cannot be made mandatory, there will be room for conflicts in practice.

Homeowners' Willingness to Participate in Energy Efficient Renovation
Homeowners' intention to undertake government-led energy efficient renovation is shown in Figure 4. A total of 84.1% of respondents would like to undertake government-led renovation, among which 46.2% would agree to bear (part of) the cost. Furthermore, 15.9% gave negative responses because they would instead take the initiative and carry out the renovation themselves or do not want to renovate.

Homeowners' Expectations and Experiences in Energy Efficient Renovation
In this part, all respondents are asked to indicate their expectations about the following two aspects: composition of the working group and content of the discussion. Those who have undertaken renovation need to answer a further question about their experiences in real projects. The setup of questions makes it possible to compare the ranking among homeowners' expectations based on respondents' vote and ranking in an actual situation based on the report of those who have undertaken renovation and explore to what extent the actual situation deviates from homeowners' expectations. The answers are collected by multiple-choice questions: based on their experiences and expectations, respondents can choose any combination of the options freely or choose none of them if nothing suits them.

Composition of the Working Group
As shown in Table 6, a total of 94 respondents that have undertaken renovation answered this question; 46 indicated that they had been approached by government employees in the working group (48.9%) and 44 mentioned neighborhood committee members (46.8%). Energy company employees (34.0%) and property management company employees (24.5%) also contributed to renovation projects. The expectation of all respondents about the same issue is shown in Table 7. Of the 465 respondents who answered this question, 325 (69.9%) preferred to have government employees in the working group. The main difference from the observation of reality lies in the other three groups. Neighborhood committee members rank the last in homeowners' expectations: only 29.9% expected to discuss with them. On the other hand, respondents indicated a request for communicating with energy company employees (48.6%) and property management company employees (32.9%). Some respondents also suggested involving architects, craftsmen, and other professional people in the discussion through the questionnaire's free feedback space. The above attitude reflects homeowners' demand for specific knowledge about the renovation. Comments collected from the free feedback space also showed that some homeowners find none of these working group members trustworthy. They expect someone who can stand on their side and speak for them as a representative of homeowners.
A comparison of the actual situation and homeowners' expectations is shown in Figure 5. The results reflect homeowners' expectations to have more chances to receive professionals' suggestions. From the homeowners' perspective, the most valuable part of communication is understanding and learning, rather than being informed and being persuaded.

Contents of the Discussion
In the questionnaire, apart from the items from the list in the MOHURD Guideline, we added two options for those who thought they had not been informed with enough information: "agree or not" means they had only been asked whether they agree on the pre-set plan, and "not been informed at all" indicates that they have not been involved in the process and no one has ever contacted them by any means. The two options are added because the interviews of practitioners revealed that the agreement procedure was skipped in some projects. Since door-to-door discussion is a time-consuming process, in many cases, it was considered as completed after working group had talked with homeowner representatives or had posted an announcement poster in the residential community. Homeowners can choose all the options that suit them; thus, the sum of the percentages is above 100%. The results are shown in Table 8. Although the MOHURD Guideline highlighted that homeowners should be informed, 42.4% of respondents indicated they had not been involved. Another 14.1% of respondents indicated they were asked to sign the agreement with a default plan and did not participate in the itemized decision-making.
The rest of the respondents mainly had participated in the discussion of "renovation measures" (37.4%), "financial plan" (29.3%), and "material" (24.2%). The difference between other options is not significant: "time plan" (19.2%) describes the schedule of the project, "maintenance methods" (17.2%) includes teaching homeowners how to use the new facilities and setting future maintenance plan, "contractor" (14.1%), and "construction team" (7.1%) refers to the selection of agencies, and "construction plan" (10.1%) describes the detailed construction plan, e.g., the arrangement of scaffolding, indoor construction, power cut, etc.
Respondents' expectations about content to be discussed indicated their strong willingness to share their opinions on all aspects of the renovation (see Table 9. Each respondent had chosen an average of four items, while those who had actual experiences were involved in only 1.7 on average. Apart from this, differences exist in homeowners' preferences to take part in the discussion towards each specific item. First of all, only 6.8% of respondents would not like to be involved at all, and 13.8% would like only to be asked whether they agree on the current plan. Reasons may be being afraid of hassle or having completely no knowledge about the renovation. As shown in Figure 6, "renovation measures" (73.1%) and "financial plan" (59.1%) remain the most concerned items, followed by "time plan" (55.3%), "maintenance methods" (55.3%), and "material" (53.4%). The interest in "construction plan" (41.9%), "construction team" (25.6%), and "contractor" (25.0%) remains relatively lower.

Factors Influencing Homeowners' Expectations
In this part, using crosstabs and a chi-square statistic, we explored the difference in homeowners' expectations about participation among different groups of people. The goal is to investigate whether socio-demographic characteristics, building features, and behavioral factors varied with homeowners' expectations. The findings can provide evidence for the working group to design targeted strategies to improve homeowners' participation.
The dependent variables include homeowners' preferred working group members and their intention to participate in the discussion. All the dependent variables are binary (yes = 1, no = 0). Regarding the independent variables, all of them are formed by mutually exclusive categories. Therefore, the data meet the specific assumptions of the chi-square test of independence. There is no chi-square result in which more than 20% of cells have an expected count of less than five, indicating a satisfying sample size.
The results of the non-parametric analysis are shown by three categories, with 12 sets of independent variables (see Table 10): • Socio-demographic characteristics: G: gender of respondent; A: age range; Occ: occupation status; Edu: highest education level; Inc: annual household income.  For the independent variables with more than two categories, if the chi-square test results indicate a statistical significance (p-value < 0.05), we conducted a post-hoc test using Bonferroni correction to determine which specific groups are statistically significantly different from each other.
About the composition of the working group, homeowners generally agree on government employees, energy company employees, and neighborhood committee members. The differences are mainly concentrated on whether to involve property management company employees: they are not preferred by homeowners that are elder or have a lower education level and those who spend more time at home because of unemployment or retirement. Meanwhile, they are relatively more welcomed by homeowners who hold a neutral or fairly good attitude towards environmental protection issues and energy efficient renovation and have some relevant knowledge.
Furthermore, compared to younger homeowners, the elder group (51 and above) prefers neighborhood committee members instead of energy company employees. Gender difference does not predict most of the dependent variables, except male homeowners tend to include government employees in the working group.
Homeowners' gender, their satisfaction of indoor comfort level, renovation experiences, and the total floor of the building is not significantly related to any discussion aspect. Homeowners will be more likely to be willing to participate in the discussion if they are relatively young, are currently under education, or have a higher education level as well as a higher income level. The intention to be involved in the discussion of the renovation measures, financial plan, construction team, construction plan, material, and maintenance methods can be predicted by certain building features or behavioral factors.
Different socio-demographic groups have the most significant deviation in time plan and maintenance methods when analyzed by decision items. The former is more concerned by the following groups: young people, students, full-time workers, and homeowners with a higher education level (at least university degree) and higher income (annual household income more than CNY 100,000 ≈ EUR 12,500) who are likely to be busier. Maintenance methods are more concerned if homeowners have a higher degree of education or income. Meanwhile, homeowners who are currently unemployed or have already retired do not pay much attention to it, nor do homeowners who are generally not concerned with environmental issues.
The explanatory power of behavioral factors is not as significant as socio-demographic characteristics. It might be partly due to the so-called "response style bias": Chinese respondents have a tendency to prefer middle response over extreme response on ratings scales [41], which weakens the differentiation of questionnaire answers.
However, some tendencies can still be concluded. It is not surprising that homeowners will be more likely to be willing to participate if they have more knowledge about the renovation or hold a more positive attitude towards the renovation. Moreover, those who are more satisfied with the current indoor comfort level are also more eager to participate in the discussion. They might worry that the current comfort level and lifestyle cannot be maintained after the renovation. Thus, they need to weigh the pros and cons more carefully to make sure that the outcome of the renovation is desirable.
Contrary to our expectations, homeowners who have undertaken government-led renovation indicated a lower level of enthusiasm to participate. One possible reason is that homeowners were dissatisfied with the negotiation they had gone through, affecting their willingness to be involved in the same process again if the situation would not be significantly improved. It is also possible that during the past renovation process, they did not perceive their presence as important to the execution of the project.

Discussion
This study reveals the current nature of homeowners' participation in energy efficient renovation in China's Northern Heating Region. Corroborating findings of numerous previous studies [4,34,38,39,42,43], homeowners' participation is undoubtedly a critical issue to decrease energy consumption in the residential sector and realize large-scale deep renovation in the future.
Some difficulties in organizing homeowners' participation in apartment buildings are also identical in other countries or regions. One reason is that property rights' complex nature increases decision-making difficulties because diverse groups of occupants may have different interests [44]. This is prevalent in different cultural and religious backgrounds. For example, in the energy efficient renovation of Lithuanian apartment buildings, it was not easy to launch the renovation process because all flats were privatized, and the renovation needed the general approval of all the building co-owners [25]. Paiho [27] mentioned that apartment buildings in Russia typically have several hundreds of units, and the homeowners are rarely familiar with each other, making it hard to achieve a collective decision. Income levels may vary among the residents of the same building, which complicates joint decision-making on building renovation [27].
Some successful attempts to involve homeowners have achieved satisfactory outcomes in other countries or regions. However, due to the uniqueness of apartment buildings, experiences generated from another cultural and institutional context may not be applied to China. Therefore, based on the understanding of Chinese homeowners' experience and expectations, we endeavor to give some recommendations that are particularly suitable to Northern China's context and may also be generalized to countries or regions with similar situations.

Improve Relevant Laws and Regulations
In countries and regions where apartment units are privately owned, and no selfmanagement forms of homeowners are established, the framework of building management is hard to build. In this study, some interviewees also mentioned that conflicts are prone to occur between homeowners and the working group because of the lack of a standardized regulation that can convince both parties. Many homeowners in old residential communities are skeptical of neighborhood committee members and property management company employees [7]. Thus, if people from these organizations force them to accept a renovation plan that will harm their interests without providing a reliable policy basis, they will be particularly rebellious. Policy support is necessary to clarify the process and avoid chaotic situations.
In many countries, homeowners' authority to participate is guaranteed at levels ranging from forming the constitution to planning regulations. There are specified procedures and steps to be followed during public participation in renovation projects. Meanwhile, in China, although the governments at the national and local level have published some programs to support housing energy efficient renovation, the audience of such programs are mainly developers and local governments. Most homeowners have never read the government's documents about renovation, nor do they know relevant policies. Thus, homeowners' intention to participate lacks sufficient encouragement; they are also unaware of their responsibilities and rights. Enhancing the presence of laws and regulations is imperative.
Adding several confirmation steps in the participation process can make it more rigorous. Every step should be justified and should follow clear regulations. Additionally, programs related to homeowners should not only focus on the pre-renovation phase and construction phase. The effect of renovation can only be ensured if the building is wellfunctioned and homeowners can adapt to it. A transparent responsibility system is needed to take care of the post-evaluation and supervision.

Establish Homeowner Associations
Homeowners' participation process in renovation projects is essentially a communication process supposed to provide homeowners with sufficient information. Some interviewees suggested that homeowners should have more chances to talk to people who are professional or in charge to gain knowledge and give feedback. However, the only approach for homeowners to communicate with other stakeholders is through a door-to-door visit, which will cost a large amount of effort and time for both working group members and homeowners, giving it relatively low efficiency. Lacking communication gives rise to misunderstandings between homeowners and the working group members and affect the process in return. It will even deteriorate homeowners' trust of the working group. When homeowners feel their interests are violated or believe they are treated unfairly, they have no trustworthy approaches to appeal. Although there is a high acceptance of energy efficient renovation at the individual level, this positive attitude may not translate into a collective decision.
A "bridge" needs to be built to connect the working group and the homeowners, through which homeowners' expectations can be better heard and treated. A possible solution is to authorize the homeowner association as a representative of homeowners, mitigating the communication cost between the opposing parties. In countries where homeowner associations have a stronger role, directors elected by the homeowners perform voluntary management work in an intensive and organized way; they are empowered to respond to important issues. In China, on the other hand, homeowner associations usually have no legal rights; however, they are generated as a grassroots power to deal with external grievances [45]. It can counterbalance different stakeholders and address homeowners' needs [46]. A homeowner association's quality of participatory representation is positively related to homeowners' level of participation; it can also help cultivate homeowners' willingness to participate in turn [47].
In addition, homeowner associations can enhance the relationship among neighbors in their daily life, and the residents in a friendly neighborhood will be more enthusiastic about participating in the management of the residential community, including the renovation decision. In apartment buildings, an individual homeowner is often unaware of the functional deficiencies of the whole building, nor do they know the problems that other homeowners are experiencing [21]. Homeowner associations can organize regular meetings or activities, which create opportunities for homeowners to communicate with each other. It can eliminate interpersonal estrangement and let people understand the situation of others better.

Develop Targeted Renovation and Participation Strategies
One of the difficulties in promoting energy efficient renovation is that every project is different. Researchers and practitioners have recognized the importance of designing renovation strategies based on the projects' physical conditions; however, little attention has been paid to the homeowners' characteristics.
In this study, we have interviewed homeowners from renovated residential communities. Despite considerable differences in their physical features and renovation measures, the homeowners' participation in these residential communities is similarly organized. However, even in the same residential community, different buildings' renovation processes and outcomes can differ significantly because the homeowners are different in many aspects. There is no one-time-for-all strategy.
Lacking homeowners' participation is only the surface phenomenon. The underlying mechanisms need to be understood and explored. There are several reasons why homeowners cannot fully participate and why their expectations deviate from reality. Some homeowners are reluctant to participate because they believe the renovation outcome is not desirable [33] and some do not realize that as the main stakeholder, they have the right and ability to participate in making major decisions [7], while in other cases, homeowners do not participate simply because they are not informed and have no idea of the upcoming renovation [39]. It requires the working group members to be patient and nuanced during the door-to-door visits because homeowners often cannot express their perceived barriers to participating directly.
The census step before the renovation is also crucial. Our results suggest that different homeowner groups may have completely different preferences. Based on homeowners' characteristics in a particular building, the working group members can estimate their concerns and requirements in advance and be prepared to solve any problems.
For example, in many old residential communities, most homeowners are low-income elderly people. They are concerned less with the time plan, construction period, and maintenance methods because they stay at home mostly and have enough flexibility to respond to any conditions; meanwhile, regarding the working group members, they have a higher tendency to prefer government employees and neighborhood committee members instead of "professional people" who may deliver information in a way that they cannot understand. On the other hand, homeowners with a higher education level are more sensitive to technical details such as renovation measures and material selection. It might be more challenging to win their trust and approval. Nevertheless, once they agree on the renovation plan, they may become the "opinion leader" and motivate others.

Conclusions
Energy efficient renovation progress in China is directly associated with homeowners' participation. In this study, we explored the current nature of homeowners' participation and found it inadequate. The participation process was divided into three elements: steps and procedures, the composition of the working group, and the content to be discussed. By investigating homeowners' experiences in renovation projects, it is possible to draw the following conclusions: firstly, the ideal procedure was often not executed in renovation projects; secondly, there is a deviation between homeowners' expectations and the reality; thirdly, the participation process should be improved. Based on the interview and questionnaire survey results, some suggestions were proposed to enhance homeowners' participation in residential energy efficient renovation in China's Northern Heating Region.
The findings of this study may also contribute to a more comprehensive understanding of homeowners' role in energy efficient renovation. Whether the renovation strategies can achieve their purpose is heavily dependent on homeowners' reactions. Further research should explore the causes of the current situation and find innovative solutions. The long-neglected aspect is possibly the critical link in the wider diffusion of energy efficient renovation.

Institutional Review Board Statement: Not applicable.
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.

Data Availability Statement:
The data presented in this study are available on request from the corresponding author.

Conflicts of Interest:
The authors declare no conflict of interest.

Appendix A Appendix A.1. Homeowners' Expectations and Experiences in Energy Efficient Renovation Survey
Thank you for participating in the survey. This questionnaire is part of a Ph.D. project to gather information about homeowners' participation and decision towards housing energy efficient renovation in the Northern Heating Region.
Please ensure that you are a homeowner that have been living in the Northern Heating Region for at least 3 consecutive years. If you are not the appropriate person to complete this questionnaire, please forward it to the correct person.
Some parts of the questionnaire are based on a brief introduction that help you to understand the questions. Please choose only one option out of all if there is a before each option, and choose all the options that apply to you if there is a before each option.
It takes about 20 min to finish all the questions. Your answers will only be used for academic purposes. Your cooperation in completing the questionnaire will ensure the success of the project.

Appendix A.2. Part I: General Perspectives
Energy efficient renovation refers to the construction work to improve the energy performance and indoor comfort level of a building or a home. For example, replacing the old windows or doors with energy efficient products, upgrading the heating system, or attaching insulation material to the walls and roofs. Currently, the average cost of energy efficient renovation project is 200 yuan/m 2 .

1.
Have you heard of 'energy efficient renovation' before?
Yes, and I clearly understand the meaning. Yes, but I didn't know the meaning. No, I've never heard of it.

2.
What is your general attitude towards energy efficient renovation?
Very positive: it should be promoted and encouraged. Positive: it sounds good, but I need more information to make a judgment. Neutral: I have no opinion towards it.
Negative: I disagree about it.

3.
Have you undertaken energy efficient renovation in the past ten years?
Yes, I have done energy efficient renovation at my own expense. Yes, I have undertaken government-led energy efficient renovation project(s), in which I paid ____ yuan. Yes, I have undertaken government-led energy efficient renovation project(s), and I was not asked to pay. No. I don't know.

Appendix A.3. Part II: Expectations in Energy Efficient Renovation Project
Now, suppose a government-led energy efficient renovation project will be going on in the residential community you live in. Someone will come to your neighborhood, discuss the renovation's content, and ask for your agreement. Then, you will have some time to make a decision-undertake or not. If 70% of homeowners in the neighborhood decided to agree on the project, it would be put into operation. Please answer the following questions based on your expectations.