Dutch housing associations, being semi-public construction clients, have been assigned an important role in helping to realize the national goal of a CO2-neutral housing stock by 2050. To achieve this goal, a growing number of housing associations have added sustainable retrofit projects into multi-year programs. Those programs are being implemented by entering into strategic partnerships with retrofit contractors. The aim of this paper is to explore the rationale behind this asset and property management approach, the process, and the organizational conditions and consequences for the partners involved. To do so, a cumulative case study for research, including seven cases, was conducted. The findings show that the rationale is primarily about improving and accelerating the retrofit process by using the knowledge, competencies, and resources of the supply-side partners as effectively and efficiently as possible. This novel approach increases the retrofit rates and tenant satisfaction with the process. Trust is key in the collaboration between housing associations and contractors. For this, partner selection is an intensive and careful process. The factor hindering the upscaling of the approach is the cultural and organizational changes needed on both the demand and supply side.

Residential energy retrofitting projects in the hot summer and cold winter (HSCW) zone of China face various risks related to project activities, which incur transaction costs (TCs), such as search, negotiation, and monitoring costs. As the leader in project implementation, the Chinese government is responsible for project planning, organisation, and coordination. However, TCs impede the government’s ability to execute risk-related project activities effectively, subsequently increasing the probability of the occurrence of risk. Drawing on transaction cost economics (TCE), this study proposes a theoretical framework to understand the barriers—such as asset specificity, uncertainty, and frequency—that prevent the government from performing project activities and mitigating risks effectively. An artificial neural network (ANN) is applied to verify the hypotheses. The results underscore experience and operational maturity in project activities, cost and time constraints, and the immature retrofitting market as significant impediments to the government’s execution of risk-related activities. Considering the varying roles of the government in reducing different risks, this study concludes by offering policy recommendations to alleviate these activity barriers and mitigate risks. By employing a TCs perspective, this study not only identifies key barriers but also deepens our understanding of risk mitigation mechanisms, providing robust policy insights tailored to the specific regional context of China, thereby enhancing both the execution and the framework of government-led retrofitting projects.

This report, therefore, focuses on the following objectives:
- Give an overview of various policy options that could target the district level, considering existing and emerging policy instruments with the potential to be successfully applied within that context, and how policy challenges specifically occurring in an urban context can be overcome;
- Develop, test and use a methodology which can be applied to identify best-practice policy instruments for specific districts by evaluating stakeholder’s acceptance of proposed policy instruments and the effects and impacts stakeholders expect for reducing carbon emissions and energy use in buildings in cities at the district level, combining both energy efficiency measures and renewable energy measures;
- Illustrate the development and assessment of innovative local policy instruments that could target the district level for achieving energy renovations and renewable energy systems;
- Provide the necessary background for recommendations to policymakers and their key partners on how they can influence the uptake of cost-effective combinations of energy efficiency measures and renewable energy measures in building renovation at the district level.

Oorspronkelijk was IEBB project 7.2 bedoeld als ondersteuning en onderbouwing van het programma De Renovatieversneller. Dit programma richt zich op de vraag-aanbodbundeling van minimaal twee corporaties en twee aanbodpartners binnen één project: oftewel een organisatie-overstijgende aanpak van de verduurzamingsopgave. Het was dan ook de bedoeling dat de nadruk in dit onderzoek zou liggen op de analyse van deze organisatie-overstijgende verduurzamingsprojecten. Dit is later door De Renovatieversneller Collectief Professioneel Opdrachtgeverschap (CPO) genoemd. Na een eerste inventarisatie (zie paragraaf 1.2) is eind 2020 besloten om de focus van het project te verleggen. De organisatie-overstijgende aanpak komt (nog) niet of nauwelijks van de grond. De bekende organisatie-overstijgende voorbeelden en initiatieven die er zijn, kregen daarnaast al veel (onderzoeks)aandacht. In de eerste plaats van de partijen die bij De Renovatieversneller betrokken zijn. Daarnaast had RVO/De Renovatieversneller Brink opdracht gegeven om begin 2021 de bestaande initiatieven nader te belichten (zie https://derenovatieversneller.nl/leerplaats). Medio 2021 is overigens besloten om tijdelijk met de Renovatieversneller te stoppen, vanwege een gebrek aan succes. Van de vier initiatieven die begin november 2020 waren ingediend, was er een te laat met de inschrijving en aanmelding. De overige drie initiatieven voldeden niet aan de voorwaarden en werden afgewezen. Wel ondersteunt De Renovatieversneller enkele initiatieven met processubsidies. Het is de bedoeling dat er een doorstart wordt gemaakt met de Renovatieversneller in 2022. De ervaringen met de eerste regeling en de geleerde lessen worden gebruikt om te komen tot een aangepaste regeling. Uit de eerste inventarisatie van voorliggend onderzoek blijkt dat er veel interessante initiatieven zijn van individuele corporaties die samen met één of meer aanbieders (aanbodketens) het onderhoud en de duurzame verbetering van hun bezit project-overstijgend aanpakken. Deze corporaties blijken vooral behoefte te hebben aan een integrale verduurzamingsaanpak van hun bezit en niet zozeer op het in engere zin energetisch verbeteren van bepaalde woningtypologieën (waarop de nadruk ligt in de Renovatieversneller). Dit onderzoek richt zich op deze project-overstijgende ontwikkelingen en initiatieven. Voordat nader ingegaan wordt op de probleemstelling en de aanpak van deze project-overstijgende initiatieven, een kort overzicht van de resultaten van de eerste inventarisatie.

Dutch policies to reach a CO2 neutral housing stock in 2050 force housing associations to realise higher renovation rates at lower costs. The potential for standardisation in renovation processes of the housing stock is huge. Practice shows that an increasing number of housing associations bundle their individual maintenance and sustainable renovation projects in renovation programs for two or more years. Programs that are then implemented in strategic partnerships with maintenance contractors. This paper clarifies the rationale behind this development, sketches internal and external factors that encourage and hinder this development and presents the effects of the shift from projects to programs. The paper contributes to the scientific body of knowledge of public clients in construction collaborating with market parties. The research provides housing associations and contractors tools for the implementation of successful partnerships. The paper is based on an explorative literature review and case-studies of strategic partnerships in this field. The findings show that strategic partnering in housing renovation programs increases the renovation rates of individual housing associations. Also the tenants' satisfaction with the renovation process is high. Trust is key in the collaboration between the strategic partners. Hindering factors are the realisation of the necessary culture and organizational changes on both the supply and demand side.

Steeds meer woningcorporaties werken project-overstijgend samen met marktpartijen bij de verduurzaming van hun woningen. Onderzoek van de Tu Delft laat zien dat deze samenwerking voor de corporaties, hun bewoners en de ketenpartners voordelig is. Het samenwerken stelt wel forse eisen aan de organisatie, het beleid en de taken en rollen van corporaties en partners. Dit artikel geeft een beeld van de algemene ervaringen bij "koplopers". Om te illustreren dat er geen blauwdruk is voor project-overstijgend samenwerken, belichten we twee voorbeelden uitgebreider: de Alliantie en ZOwonen.

Energy retrofit of residential buildings is an approach to reduce worldwide energy consumption. Residential energy retrofitting in China mostly focuses on multi-owner residential buildings with composite ownership that dozens of private homeowners own their apartment and jointly own the common parts of a building. The implementation of residential energy retrofit faces many risks, causing the slow retrofit process in the hot summer and cold winter (HSCW) zone of China. Transaction cost theory (TCT) is conducive to enrich an in-depth understanding of risk inventories in the energy retrofitting context. This paper aims to explore the key risks in retrofit projects of residential buildings in the HSCW zone with transaction costs (TCs) considerations, in order to provide the direction for effective risk management. First, based on the theoretical risks with TCs considerations, interviews were conducted to adjust the risk list and to connect these risks with stakeholders and stages. Second, a questionnaire survey was made based on two parameters of risk probability and severity, and then ten top risks were chosen as key risks through both a risk matrix and Borda count. The results show that most of the key risks are associated with homeowners and contractors, involving retrofit awareness, cooperation performance, opportunism, professional expertise, construction management, safety management, and maintenance, of which most occur at the stage of on-site construction. Information cost is the largest source of TCs relevant to these key risks and is mainly borne by the government and homeowners. TCs can also provide a lens for the retrofitting in other countries to understand risks, and the decrease in information costs contributes to effective risk management both in China and in the international context.

The process of residential energy retrofitting needs to be advanced, especially in the hot summer and cold winter (HSCW) zone of China. Good cooperation from homeowners is the key to the smooth project implementation. Some studies have identified four categories of information as important factors affecting homeowners' decision-making in retrofitting. Such information can improve homeowners' cooperation to some extent. This paper investigates the nature of this influence mechanism of retrofitting information, so as to stimulate homeowners' cooperation. The authors, first, explain how the direct relationship between information and homeowners' level of cooperation is validated. Second, under the mediation role of risk perception, we verify the indirect influence of such information. Third, we analyse the variation in the strength of the relationships between information and homeowners' cooperation under the influence of source credibility. It is concluded that providing information on retrofitting benefits and service is more effective for improving homeowners’ cooperation. The integrity of building quality information and the understandability, to the homeowners, of technology information need to be considered. Priority should be given to the sources of expert knowledge and published resources, because they are perceived by homeowners to be relatively credible. Policy suggestions are proposed based on the results.

To be successful, energy renovation construction programs in northern China require both proper understanding of the causes of quality failures and effective strategies for renovating existing residential buildings for energy savings. However, surprisingly, although in recent years more attention has been focused on studying quality failures and reducing their causes, such failures still frequently occur in building energy renovation projects. In practice, the causes are not isolated, but rather, stem from complex correlations that impede high-quality performance. Due to their neglect of the causal relationships among these factors in quality failures, project coordinators have been unsuccessful in managing the quality of construction projects. Considering a network of different causes, this work reports on efforts to identify and manage the causes of quality failures in construction processes. A new understanding of the nature of these causes was achieved by considering four sources of data: literature review, opinions of experts, interpretive structural modeling (ISM), and focus groups. Our analysis shows that not only do many causes directly influence construction quality in building energy renovation projects, but also these causes interact with each other. It is noteworthy that external causes remain associated with all internal causes. Drivers of these causes are lack of experienced project managers, unauthorized changes in design documents, incomplete building information in projects, and poor onsite coordination; eliminating them enables solutions to a number of other internal causes. Finally, solutions are proposed to improve the current situation. These solutions fall into the categories of people, materials and equipment, design, and organization, based on the quality management process. The findings of this work provide valuable information for helping both policy makers and practitioners adopt effective policies and measures to manage the construction quality of building energy renovation projects.

The renovation of housing stock in the Netherlands has the potential to help achieving the country's climate change targets. However, there are non-monetary Transaction Cost (TC) factors, such as searching for information and finding a reliable professional/contractor, that present barriers to householders when making the decision to renovate or not. This study evaluates the impact of the transaction costs on the renovation decision-making process for two groups of householders, current renovators and potential renovators, and for three types of renovations, exterior renovations, interior renovations, and energy efficiency renovations. The study analyses householder renovation decisions in relation to TC barriers at different stages of the renovation processes. The data was collected from a survey of 3,776 homeowners in the Netherlands. The main identified TC barriers were found to be at the consideration, decision, and execution phases of the renovation decision-making process, and are: finding a reliable professional/contractor to do exterior renovations, determining costs for interior renovations, and finding ways to increase the energy efficiency of the house using energy-saving renovations. The main sources of information for householders are construction stores/Do It Yourself (DIY), installations and maintenance companies for exterior and energy efficiency renovations, while for interior renovations it is construction stores/DIY companies, Internet, and recommendations from family/friends. The findings from this study contribute to more effective management and distribution of both information and financial resources in relation to the renovation of housing stock.

Building energy renovations can effectively improve the environmental performance and energy sustainability of existing buildings. From 2007 onwards, the Chinese government has promoted energy-saving renovations of existing urban residential buildings. Nevertheless, various quality failures happen during the construction period in energy-saving renovation projects of residential buildings. Yet, the causes and their characters remain largely unknown. Through a literature review, this paper investigates the causes of quality failures. Validated through experts’ interviews, a total of 18 causes were identified in building energy renovation projects. These causes were analyzed from two main aspects: the importance of a cause (related to impact and frequency), and the level of effort required to address a cause (related to origin and scale), using both a questionnaire survey and a focus group. The results indicate that the critical causes of quality failures are working under high-cost and high-time pressure, adverse natural conditions, fraud of construction companies, incomplete construction site survey, poor checking procedures of supervisors, poor operational skilled workers, inadequate equipment performance, lack of experienced project managers, and incomplete building information in projects. The causes were classified as external and internal causes of building energy renovation projects. The outcome of this paper should aid policy makers and project coordinators to focus on critical causes of quality failures, and to develop effective actions and policy interventions to achieve successful renovation projects with high-quality performance

The implementation of energy retrofit of residential buildings faces many risks around the world, especially in China, leading to low retrofit progress. Stakeholders’ proactive risk management is the key to the smooth implementation of retrofit projects but is normally affected by risk perception. Perceived risks instead of real risks are the motivators of their proactive behaviours. This paper aims to understand and address the present risk perception of stakeholders in order to drive effective proactive risk mitigation practices. Based on a risk list identified through a literature review and interviews, a questionnaire survey was then made to analyse and compare different stakeholders’ perceptions of each risk by measuring the levels of their concern about risks. It is validated that all the stakeholder groups tend to mitigate risks perceived highly proactively. Proactive risk management of risk-source-related stakeholders deserves more attention and responsibility-sharing with transaction costs (TCs) considerations contribute to the enhancement of risk perception. More responsibilities of construction quality and maintenance is taken by the government and contractors should be clarified, and the government should also be responsible for assisting design work. Effective information is beneficial to the decrease in homeowners’ risk perception that can motivate their initiative of cooperation.

Building energy renovations contribute significantly to energy sustainability and environmental protection. These advantages have increased the importance of renovating existing residential buildings in many countries. In China, the government has supported the energy-saving renovation of existing urban residential buildings since 2007. However, quality failures, which do not meet the technical requirements, occur during construction processes in building energy renovation projects. Although quality failures are regarded as a crucial problem in building energy renovation projects, the identification of quality failures and their sources, likelihood, impacts, and causes remain mostly unknown. This paper investigates the nature of quality failures in building energy renovation projects. A total of 25 quality failures were first identified through five cases, and interviews with six experienced construction professionals in China. A questionnaire survey was further conducted to evaluate the frequency of quality failures. The results show the nature of quality failures that arise during construction and their sources, occurrence frequency, causes, and impacts. The research reveals that quality failures are caused by defaults by workers; inadequate checking procedures; incomplete construction site surveys; inaccurate design work; fraud of construction companies; and inefficient cooperation between different departments. Above all, the behaviors of the main actors are responsible for poor construction quality. Additionally, emphasis on quality control during the renovation preparation stage is critical to ensure that quality failures are reduced in numbers and severity.

The European Commission aims to decrease GHG emissions to 80% below 1990 levels by 2050 (EU, 2017). The housing stock has a considerable share that equals to 40% of energy consumption and 36% of emissions in the EU. The current research aims to evaluate the homeowners' energy renovation decisions on the exterior, interior, and insulation/installation of their house. The householders' renovation decisions are analyzed with regards to (1) which stages to help/support and (2) what information is essential in the renovation process. Considering the extent of difficulty for private homeowners' in accessing information and complexity in conducting the renovation, transaction cost (TC) theory is applied in understanding the decisions. The data has been collected through a survey among 3,776 of the Dutch homeowners in 2012. Then, statistical and logistic regression analysis has been conducted to analyze the renovation decisions for two groups of homeowners: renovators and potential renovators. According to the results and the outcomes of this study: (1) For the renovators: (a) the main identified stages in getting help are in carrying out the renovation, determining the costs, and looking for the reliable professional/ contractor, (b) the main identified sources of information are at the maintenance/ installation companies, family/ friends, and via internet; (2) For the potential renovators: (a) the main identified help stages are in determining the costs, looking for a reliable professional and carrying out the renovation/ improvement, (b) the main identified sources of information are via the internet, by a maintenance/ installation companies, and family/ friends. The main difference among the renovators is for insulation/ installation. The most significant stage in getting help for insulation/installation is to find out the most efficient solutions. Similar results have been found for the potential renovators; the only difference was in the order of the influencing factors.

The housing stock has a considerable share of 40% in energy consumption and 36% of CO ₂ emissions in the EU. In accordance to energy efficiency and emissions targets set by EU, The Netherlands has aimed to renovate 300,000 homes each year, leading to 50% reduction in CO ₂ emissions, by 2050. Many factors including low renovation rates create uncertainties in achieving these targets. The current study aims for understanding the barriers and drivers towards energy efficiency renovations (EERs) amongst Dutch homeowners, and to aid in gaining a better insight into the role of public authorities in promoting EERs. First, the extrinsic drivers, including policies and other initiatives in the EER process are explained. Second, the intrinsic drivers and intrinsic/extrinsic barriers are explored. Regression analyses are performed on the national Dutch survey data for renovators and potential renovators. Our main findings include: (a) desire to enhance the quality of their life, rather than the financial benefits, etc. is identified as the main driver; (b) the main barriers are the costs of EERs, complexities in the process, information barriers, and finding reliable experts and information; (c) For improvement in meeting renovation targets, the current Dutch policies need to consider all the decision criteria by homeowners, such as: Reducing the complexities; Time needed to obtain loans and subsidies; and Facilitating access to information.

The housing sector is responsible for a more than a quarter of the total final energy consumption in the EU. As the majority (70%) of the EU-housing stock is owner occupied and largely consists of single family dwellings it is understandable that many countries focus their energy saving policies on homeowners. Complementary to the national policy frameworks, regional and local authorities implement locally based policy instruments targeting specific groups and individual homeowners. In order to enlarge the effectiveness of their policy instruments and to reach the energy saving goals, frontrunner local authorities in particular are searching for ways to reach homeowners. Consultancy centres and pop-ups can be a way to make individual homeowners more aware about their energy use and stimulate them to apply low carbon technologies. The research results not only show that a wide range of business models are available to develop, structure and organise these consultation centres and pop-ups, but also that they indeed could play an important role in accelerating the energy performance of owner occupied housing. Through a pop-up or consultancy centre, public and private parties can join their forces to reach, stimulate and support the individual needs and wishes of homeowners during their customer journey to realise an energy efficient dwelling

This report answers the question: How can HEMS be used to influence energy-saving behaviour of homeowners? Lessons regarding the feedback from HEMS to influence energy-saving behaviour have been explored and specifications of HEMS to influence energy saving by households are given.
Generally, the implementation of the Triple-A HEMS should appeal to (1) end-users (households) and (2) local authorities. Triple-A partners will provide HEMS to households to encourage them to change their energy behaviour and to trigger interest in the adoption of low carbon technologies. Another goal is to apply HEMS in demonstration exemplars (WP 4) to monitor the energy consumption of households and analyse consumption data before and after applying low carbon technologies.
HEMS with real time feedback have a good potential to influence the energy use and subsequent savings of households. In order to realise a structural change of the energy use behaviour it also must become customary for households to use the feedback system. The need of forming an energy saving habit also sets demands on the functionality and design of the feedback system. It must meet the preferences, capabilities and interest of a heterogonous group of homeowners or should be designed for specific customer segments. Direct feedback instruments primarily influence low-cost-quick-win measures: simple changes in behaviour that require little or no effort or investments. These behavioural changes however can potentially lead to substantial immediate savings.
The rollout of smart meters and HEMS differs strongly between the EU countries and the Triple-A countries. Energy providers can play an important role in the rollout of HEMS. The use of smart meters and HEMS and providing easy access of HEMS to homeowners could be one of the instruments of local energy saving programs and community-based reinforcement strategies of local authorities. A neighbourhood approach aims to enable more positive outcomes for energy savings and uptake of renovation measures, by using peer-to-peer communication, personal advice, trialling in demo houses and demonstration in pop-up centres and on local authority websites.
To monitor actual CO2 savings by local authorities within the demonstration areas, baseline requirements for HEMS deal with recording (or accessing data related to) annual energy use gas and/or electricity within the properties for a period of 12 months before and after installation. Next to baseline requirements local authorities can choose discretionary functions and requirements of HEMS, including e.g. measuring grid energy monitoring and comfort performance.
HEMS will also be used to give real-time feedback of the energy use to homeowners helping them to manage their energy consumption. For this purpose recommendations are:
• HEMS should be easy to use and accessible, and fit for purpose.
• Feedback should be real-time, frequent feedback enables the user to link behaviour to consequences.
• The specifications of the HEMS should match with the household characteristics and the willingness to use HEMS. A distinction between user groups is advisable: some users explicitly have more interest in more functionalities (and thus a more complex HEMS, others want a more intuitive user interface.
• Whether adoption of HEMS leads to the adoption of renovation measures is not (yet) known.
• HEMS should appeal to certain conditions of the homeowner (segments) or to solving issues within the home.
Overall recommendations for choosing HEMS include:
• The HEMS should be cost-effective.
• The installation of the HEMS should be easy (preferentially without electricity connection).
• The intrusion time for installing in the home should be minimized.
• A preference is given for HEMS that local authorities can experiment with free-of-charge to avoid de minimis statements.
• HEMS choice by local authorities will be influenced by the need to follow up KPI’s for energy saving, and thus by the compatibility with their own energy management system for analysing building stocks.

Local authorities engaged in the Interreg 2 Seas project Triple-A want to achieve a market acceleration in the owner-occupied single-family home renovation sector by increasing awareness of - and enabling access to – energy saving technologies. Various local authorities are particularly looking for opportunities to improve their communication channels using novel web functions. This report looks into opportunities for stimulating homeowners to adopt energy-saving technologies by improving municipal communication channels, particularly web portals. First, literature research reflects on the influence of communication channels on homeowner renovation decision-making processes. The research further provides an inventory of strengths and weaknesses of existing web portals aimed at awareness raising among homeowners and reflects on new web platform developments. Secondly, data on current web portals of local authorities were collected from local authorities in four countries (Belgium, France, The Netherlands, UK). The qualitative analysis compares existing local authorities’ web portals against key characteristics for providing homeowner support, to identify potential for improvement. Thirdly, local scoping workshops were organized in seven local authorities to determine most effective modules to improve local authority web portals. A demo workshop resulted in a list of desired web functions for local authorities. Local discussion with stakeholders revealed the main opportunities and barriers for improving existing local authority web portals and a selection of at least five web functions for immediate development. The research resulted in a long-term perspective on web portal development and a set of modules and recommendations for strengthening local authorities’ web portals for increasing awareness and easy access to low carbon technologies. Based on this, seven local authorities identified the most effective modules to improve their web portals in the short term in co-creation with stakeholders.

Local authorities engaged in the Interreg 2 Seas project Triple-A aim to achieve a market acceleration in the owner-occupied single-family home renovation sector by increasing awareness of – and enabling access to – energy saving technologies. Various local authorities are considering using consultation centres and pop-up models (or pop-up centres) as additional opportunities to reach their goals and to improve their communication with homeowners. This report analyses the experiences and opportunities that various models of consultancy centres and pop-up models can offer to stimulate homeowners to adopt energy-saving technologies. In the first place experiences of already existing consultancy centres and pop-ups in the four countries of the Triple-A partners were analysed (Belgium, France, The Netherlands, UK). The customer journey model (e.g. the process starting with creating awareness, providing information up to the execution of energy saving measures) was used as the framework to reflect on the needed activities in centres and related pop-ups. The various examples are described in a short, concise format and were chosen because they illustrate the wide range of possible pop-up concepts. Secondly the specific needs and wishes of the Triple-A partners were assessed. Via a questionnaire the partners were asked how they intended to use consultation centres and pop-ups (e.g. what kind of information do they want to provide in what way, to what target group?) and what kind of model they had in mind (e.g. a more permanent centre or a temporary pop-up?). Workshops were organised (held in Antwerp on the 13th October 2017) with the LA’s to determine and specify their wishes on business model development not only to determine possible pop-up model concepts but also to address public-private cooperation in this field. As a further illustration and as sources of possible inspiration the business models of a few selected existing consultation centres were reviewed in depth (Woon+bus, Kyotomobiel and EcoHuis in Belgium and Reimarkt and ICDuBo in the Netherlands). These few selected case were chosen because they fitted in within the Triple-A business models that have been formulated at the beginning of the project.