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This paper examines experiences with the diffusion of the passive house concept, applied to the situation of ‘emerging’ countries like Belgium and the Netherlands. Adopter categories considering the passive house concept are defined. A marketing study based on Rogers’ theory of diffusion of innovations highlights the characteristics of actors leading to technological and process innovation. The paper draws conclusions on the preferred role of passive house networks.

This paper examines if and how indoor climate systems are important for passive house certification. The research subjects are passive houses in Belgium, occupied by owner-clients. These have received a quality assurance certificate from an independent organization. Through interviews with the owners, and on-site analysis of indoor climate installations in passive houses, the selection of indoor climate systems for passive houses was analyzed and insights were obtained in changes occurring after certification. Also, two houses were analyzed during further visits, including interviews and measurements, to allow detailed performance evaluation of the indoor climate systems. The paper concludes that adaptation of certification procedures is recommended, by looking more closely at the practical implementation of indoor climate systems. The paper further questions the general validity of the scientific basis of the passive house definition.

According to the definition, passive houses in Europe meet a target energy demand for heating of less than 15 kWh per square meter and per year. This low level for the heating demand is based on heating by a small post-heater in the hygienic ventilation system at 52 °C maximum, while the ventilation system can be dimensioned purely for ventilation purposes. In theory thus the installed heating power is less than approximately 10 Watts/m2. But what happens in practice in renovations? Example projects of low energy housing retrofits and their indoor climate systems in winter and in summer were examined. The study includes inspection of technical details and interviews with occupants of some renovation projects. It is shown that the practical realization of very low energy houses can be different from the original passive house definition, but also that the passive house standard is feasible in difficult conditions. The results illustrate the concerns of occupants considering winter and summer comfort and health, and the difficulties of choosing adequate ventilation and backup heating when the passive house standard is not reached. Also, a good realization of (passive) cooling and solar shading is a very important issue. The research further illustrates tendencies in innovation considering design of ventilation systems for renovation purposes, including possibilities of space reduction, prefabrication, decentral heat recovery and improved user friendliness of indoor climate systems for passive houses.

For newly built houses and renovations European and national ambitions prescribe increasing levels of energy performances, even including achieving the passive house standard, net zero energy or carbon neutral houses. For highly energy-efficient renovation, project information from first demonstration projects is now becoming available. This paper examines experiences of demonstration projects with improved energy performance, in order to diffuse these experiences to reach other innovators and the early adopter market. Innovation diffusion theory is used to analyse examples of residential renovations using passive house technologies. Further the paper examines challenges and opportunities for the diffusion of demonstrated solutions to an early adopter market. Detailed case studies show that passive house retrofit, as well as low energy retrofit, need more holistic approaches, higher skill competence and strong process coordination. The results show that it is technically feasible to reach outstanding energy performance in renovation. However, social, political and economical issues remain important barriers to reach a more substantial market share. In particular there is a need to cluster energy efficiency principles to focus on substantial energy savings. The research leads to ideas for further study of the possible role of change agencies to support substantial energy reduction in retrofit projects.

This study examines opportunities for the emergence of SME networks regarding highly energy-efficient housing, as well as the barriers they face. A theoretical innovation diffusion model is developed from the point-of-view of social and environmental entrepreneurship and sustainable consumption. The qualitative analysis reflects key elements from the theoretical model and is based on a representative case study of a successful passive house network located in the Belgian Flemish Region. Data were gathered during the emergence of the network, by means of participant observation and action-based (thematic innovation) research. Interviews provided further supplementary information. The study concludes that the successful emergence of an SME network regarding highly energy-efficient housing requires a holistic approach, in which both enterprises and clients are guided in each step of the innovation-decision process. In their role as intermediaries between clients and firms, change agents should be supported by policy that facilitates networks for innovation diffusion.

In previous years we have seen a recognition of the significant potential that exists for reducing energy use through innovation in residential buildings. This study investigates innovation challenges and identifies opportunities that could lead to a rapid increase in the adoption of highly energy-efficient housing concepts, particularly that of the passive house. To this end, it exemplifies, interprets and develops the innovation adoption theory through an investigation of views and experiences on the supply side, the demand side and the policy side. It highlights successful innovation trajectories and barriers experienced by businesses. It addresses both problems and positive experiences from the perspective of the end user and investigates different policy approaches. As such, the research reveals important features of innovation-adoption strategies in the building sector. It shows how multi-player enterprise collaboration plays a key role, and the study also recommends the development of quality assurance schemes. It makes a valuable contribution to discussions about how active a role government policymakers and enterprise networks should play.

In previous years we have seen a recognition of the significant potential that exists for reducing energy use through innovation in residential buildings. This study investigates innovation challenges and identifies opportunities that could lead to a rapid increase in the adoption of highly energy-efficient housing concepts, particularly that of the passive house. To this end, it exemplifies, interprets and develops the innovation adoption theory through an investigation of views and experiences on the supply side, the demand side and the policy side. It highlights successful innovation trajectories and barriers experienced by businesses. It addresses both problems and positive experiences from the perspective of the end user and investigates different policy approaches. As such, the research reveals important features of innovation-adoption strategies in the building sector. It shows how multi-player enterprise collaboration plays a key role, and the study also recommends the development of quality assurance schemes. It makes a valuable contribution to discussions about how active a role government policymakers and enterprise networks should play.

Europe expects the housing sector to evolve towards ‘nearly zero-energy’ dwellings. Meanwhile, general terms and research, marketing and legal definitions considering such dwellings have already been introduced. Appraisal of existing definitions is now needed for further policy development. This paper examines what nearly zero-energy terms can be expected to be adopted in Belgium and the Netherlands. The research method uses an interview method based on innovation diffusion theory. The analysis traces the regional adoption trajectory of relevant definitions and examines the opportunities and barriers for the inclusion of existing definitions in regional energy policy. The analysis shows that—whilst international prominence of the terms ‘net zero energy’ and ‘net zero carbon’, in addition to ‘low energy’ and ‘passive house’, is observed—in Belgium and the Netherlands ‘passive house’ and ‘energy neutral’ are preferred. The research findings indicate that the adoption of already existing definitions for nearly zero-energy houses will depend on the region and can prove a very complex process with several conflicting issues. Terms should be clearly defined and used at all political and marketing levels. It is recommended to enhance the relative advantage, demonstrability, visibility and compatibility of favoured definitions by policy initiatives

For the realization of the first passive house demonstration projects in Belgium, passive houses were requested by convinced clients, designed by architects with experience in low energy building, and built by contractors with a feeling for working in building teams. These first passive house examples were not limited to one specific building system, but already showed a diversity in technical solutions. Due to networking initiatives and financial stimuli, the demand for passive houses has grown exponentially in Belgium, like in other European countries. Nowadays, clients base their decisions on available grants and tax reductions, any architect is consulted for building a passive house and many contractors still lack experience and practical information. The Presti 5 research project ‘Details in the passive house standard’ acknowledged this lack of practical information. Its goal is to multiply the realization of good construction solutions to assure the quality of construction of further passive houses. This is done by defining and spreading practical design outcomes for the Belgian building situation, providing both design and construction information. In collaboration with the building industry and knowledge institutes, building details are designed and established for both massive and wood construction of passive houses, linking the innovative construction techniques of a passive house to the Belgian building tradition. Working groups were formed that discussed these details on a regular basis. Thus, in the scope of less than one year more than 10 fundamental building details have been finalized, in agreement with building industry and knowledge institutes. This paper gives an overview of the existing innovative solutions in Belgian passive house construction, discusses experiences and the potential of the related research process, and discusses examples of construction details in passive house standard, with specific concern for the thermal quality and air tightness. The building details will shortly be spread to all Flemish architects in order to multiply the local knowledge on passive house construction. It is recognized that with the current state of the building market, good building details are essential for the broad introduction of passive houses. Finally further research ideas are discussed.

For newly built houses national ambitions prescribe increasing levels of energy performances, even including achieving net zero energy or carbon neutral houses. This is in large contrast with the lack of quality in many building processes. The building regulations, processes and control will have to be reshaped to support these ambitions, taking into account a development of performance guarantees in the building sector. Passive houses have to reach a target energy demand for heating less than 15 kWh/m2a and a total primary energy demand less than 120 kWh/m2a. Quite some examples of houses (and other buildings) in various countries show that it is technically feasible to reach this performance. In most of these countries also some form of quality assurance and certificates for these houses exist. In this paper we describe the possible changes of building processes due to the introduction of the passive house concept, and the urgency of reliable quality assurance to adequately reaching the energy ambitions and to assure quality issues at the same time. We illustrate this with passive house certification schemes from some European countries. This leads to some conclusions about the role and content of passive house certificates in the coming years.

According to the popular definition, passive houses have to reach a target energy demand for heating less than 15 kWh per square meter and per year. This criterion is used as a basis for quality assurance procedures and certification of passive house projects. This paper identifies the experiences in several western European countries concerning passive house certification, and hence the control of quality of the design process, the construction process, and the post construction inspection and testing of passive houses. Certification and quality assurance initiatives from Belgium, the Netherlands, France, the U.K. and Ireland are compared with preceding initiatives in Austria, Northern Italy, Switzerland and Germany. It is recognized that with the current state of the emerging passive house market, passive house verification is necessary on a project level, but that it is still difficult to introduce certification of actors and processes in many countries. An open market and competition for certification

According to the definition, passive houses in Europe meet a target energy demand for heating of less than 15 kWh per square meter and per year. This low level for the heating demand is based on heating by a small post-heater in the hygienic ventilation system at 52 0C maximum, while the ventilation system can be dimensioned purely for ventilation purposes. In theory thus the installed heating power is less than approximately 10 Watts/m2. But what happens in practice? The practical realization can be different from the definition and user experiences with indoor climate systems for passive houses may require further adaptations. Belgian example projects and the indoor climate systems in winter and in summer were studied. The study includes inspection of technical details and interviews with occupants of some passive houses in Belgium. The results illustrate the concerns of occupants considering winter and summer comfort in especially bedrooms, low air humidity creating respiratory problems and complex control of installations including temperature control. The research shows that occupants tend to prefer new adapted types of post-heating. Also, a good realization of (passive) cooling techniques is a very important issue in passive houses. The paper gives recommendations on how to improve the user friendliness of indoor climate systems for passive houses.