Greater potential energy savings can be achieved in the large stock of existing dwellings than in the relatively small proportion of newly built dwellings. Although the energy performance of existing dwellings is much poorer than new dwellings, the stock of existing dwellings is very large in a ‘mature’ built environment of most developed countries. In the past decade, awareness of the potential energy savings has spread widely among the many stakeholders involved. Nonetheless, most regulations and instruments are still aimed at achieving sustainable newly built construction. An evidenced-based overview of the current state of the residential building stock is provided for eight northern European countries along with current renovation data. Comparisons are made on the characteristics, physical quality and developments of the residential building stock. Existing policies and incentives to reduce energy use and CO₂ emissions are analysed for their impacts on the existing building stock as well as the barriers preventing successful sustainable renovation. Common denominators in the current state of renovation of residential building stock are used to identify possible future instruments and incentives that are needed to overcome current barriers. C'est dans le parc important des logements existants plutôt que dans le pourcentage relativement faible des logements de construction récente qu'il y a le plus de possibilités de réaliser des économies d'énergie. Bien que la performance énergétique des logements existants soit bien moindre que celle des logements neufs, le parc des logements existants est très important dans un cadre bâti parvenu « à maturité », tel que celui de la plupart des pays développés. Dans la dernière décennie, la sensibilisation aux économies d'énergie pouvant être réalisées s'est largement répandue parmi les nombreuses parties prenantes impliquées. Néanmoins, la plupart des réglementations et des textes réglementaires visent encore à obtenir une durabilité dans des constructions neuves. Un panorama, fondé sur des données probantes, de l'état actuel du parc bâti résidentiel est fourni pour huit pays d'Europe du Nord, accompagné des données actuelles en matière de rénovation. Des comparaisons sont faites concernant les caractéristiques, la qualité physique et les évolutions du parc bâti résidentiel. Les politiques existantes et les mesures incitatives destinées à réduire l'utilisation d'énergie et les émissions de CO₂ sont analysées quant à leurs effets sur le parc bâti existant, ainsi que les obstacles qui empêchent de réussir une rénovation durable. Les dénominateurs communs propres à la situation actuelle en matière de rénovation du parc bâti résidentiel sont utilisés afin d'identifier les futurs textes réglementaires et les futures incitations possibles qui sont nécessaires pour surmonter les obstacles actuels. Mots clés: qualité des bâtiments, parc bâti, performance énergétique, politique énergétique, économies d'énergie, politique du logement, rénovation, durabilité, qualité thermique

Current practices show that the goals of energy saving and CO₂ reductions for creating an energy-neutral building stock can only be reached by strict and supportive governmental policies. In Europe the Energy Performance of Buildings Directive (EPBD) and the Energy Efficiency Directive (EED) are driving forces for member states to develop and strengthen energy performance regulations both for new buildings (via building approval procedures) and the existing building stock (via energy performance certificates or labels). The effectiveness of these current governance instruments and their impact on actual CO₂ reductions are found to be inadequate for ensuring actual (not hypothecated) energy performance is achieved. To realize the very ambitious energy-saving goals a radical rethink of regulatory systems and instruments is necessary. Building performance and the behaviour of the occupants is not well understood by policy-makers. Alternative forms of governance are needed that have more impact on the actual outcomes. Supportive governance to stimulate near-zero renovations in combination with performance guarantees is a promising approach. Furthermore, engagement with occupant practices and behaviours is needed. To ensure accurate outcomes-based governance, a better understanding of building performance and behaviours of occupants must be incorporated.

This study investigates the integration of green hydrogen into building energy systems using local solar power, with the electricity grid serving as a backup plan. A comprehensive bottom-up analysis compares six energy system configurations: the natural gas grid boiler system, all-electric heat pump system, natural gas and hydrogen blended system, hydrogen microgrid boiler system, cogeneration hydrogen fuel cell system, and hybrid hydrogen heat pump system. Energy efficiency evaluations were conducted for 25 homes within one block in a neighborhood across five typological house stocks located in Stoke-on-Trent, UK. This research was modeled using a spreadsheet-based approach. The results highlight that while the all-electric heat pump system still demonstrates the highest energy efficiency with the lowest consumption, the hybrid hydrogen heat pump system emerges as the most efficient hydrogen-based solution. Further optimization, through the implementation of a peak-shaving strategy, shows promise in enhancing system performance. In this approach, hybrid hydrogen serves as a heating source during peak demand hours (evenings and cold seasons), complemented by a solar energy powered heat pump during summer and daytime. An hourly operational configuration is recommended to ensure consistent performance and sustainability. This study focuses on energy performance, excluding cost-effectiveness analysis. Therefore, the cost of the energy is not taken into consideration, requiring further development for future research in these areas.

The energy management systems industry in the built environment is currently an important topic. Buildings use about 40% of the total global energy worldwide. Therefore, the energy management system’s sector is one of the most influential sectors to realize changes and transformation of energy use. New data science technologies used in building energy management systems might not only bring many technical challenges, but also they raise significant educational challenges for professionals who work in the field of energy management systems. Learning and educational issues are mainly due to the transformation of professional practices and networks, emerging technologies, and a big shift in how people work, communicate, and share their knowledge across the professional and academic sectors. In this study, we have investigated three different companies active in the building services sector to identify the main motivation and barriers to knowledge adoption, transfer, and exchange between different professionals in the energy management sector and explore the technologies that have been used in this field using the boundary-crossing framework. The results of our study show the importance of understanding professional learning networks in the building services sector. Additionally, the role of learning culture, incentive structure, and technologies behind the educational system of each organization are explained. Boundary-crossing helps to analyze the barriers and challenges in the educational setting and how new educational technologies can be embedded. Based on our results, future studies with a bigger sample and deeper analysis of technologies are needed to have a better understanding of current educational problems.

In this review article, our main goal is understanding the Networked Learnings used for professional development. Networked learning can be defined as a form of learning where information and communication technology (ICT) can be used to promote connections between learners and their peers, learners and tutors and learners and learning resources. Such networks play an important role in professional development of employees in different sectors, from high tech industries to traditional businesses, and in both formal teaching and educational programs and informal learning activities. In this review, we explore how networked learning contexts, domains, and levels of scale are practiced and reported in the academic literature. And finally, we will investigate support technologies that have been used to facilitate networked learning for professional development.