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The next level of energy performance of new buildings within the European Union will be the Nearly Zero-Energy Building (NZEB). A lot of work has been spent on pilot and demonstration buildings on this and even higher energy performance levels throughout many EU countries. However, most of the high performance buildings realised so far result in additional investment costs when compared to the current national minimum energy performance requirements. The considerably higher investment costs are one of the main barriers to the early application of the NZEB-level in Europe. The EU Horizon 2020 project CoNZEBs works on technical solution sets that result in lower investment costs for NZEBs, bringing the costs close to those of conventional new buildings. The project focus is on multi-family houses. In each of the four participant countries Germany, Denmark, Italy and Slovenia a team of researchers is analysing which sets of market-ready technologies at the building envelope, the services systems for heating, domestic hot water, ventilation and cooling (where required) in combination with renewable energy systems can fulfil the NZEB requirements at lower costs than those incurred by the national mainstream NZEB application. Additional efforts are being spent on the life-cycle costs and the life-cycle analysis of the solution sets, as well as on the impact of future developments of primary energy factors, energy costs and technology efficiencies. Since details of the CoNZEBs work are presented in several additional papers, this document gives an overview of the different tasks and results that are available so far. The next level of energy performance of new buildings within the European Union will be the Nearly Zero-Energy Building (NZEB). A lot of work has been spent on pilot and demonstration buildings on this and even higher energy performance levels throughout many EU countries. However, most of the high performance buildings realised so far result in additional investment costs when compared to the current national minimum energy performance requirements. The considerably higher investment costs are one of the main barriers to the early application of the NZEB-level in Europe. The EU Horizon 2020 project CoNZEBs works on technical solution sets that result in lower investment costs for NZEBs, bringing the costs close to those of conventional new buildings. The project focus is on multi-family houses. In each of the four participant countries Germany, Denmark, Italy and Slovenia a team of researchers is analysing which sets of market-ready technologies at the building envelope, the services systems for heating, domestic hot water, ventilation and cooling (where required) in combination with renewable energy systems can fulfil the NZEB requirements at lower costs than those incurred by the national mainstream NZEB application. Additional efforts are being spent on the life-cycle costs and the life-cycle analysis of the solution sets, as well as on the impact of future developments of primary energy factors, energy costs and technology efficiencies. Since details of the CoNZEBs work are presented in several additional papers, this document gives an overview of the different tasks and results that are available so far.

The paper presents the findings on end-users' experiences and expectations about living in multi-family Nearly Zero-Energy Buildings (NZEBs). The survey in four European countries (Slovenia, Italy, Denmark and Germany) was part of EU Horizon 2020 project CoNZEBs (2017-2019) and addressed end-users living or thinking about living in multi-family NZEBs. Targeted end-users were living (as tenants or owners) in either ordinary buildings or in high performance buildings such as NZEBs (mandatory after 2020 according to Directive 2010/31/EU). In the survey, the following topics were addressed: the level of end-user's understanding of the NZEB concept, the source and quality of information on NZEB from the end-users' perspective, the importance of various apartment features for the end-users, perception of NZEB characterizing technologies, and decision triggers for living in NZEB. Concerns, doubts and eventual fears about living in NZEBs were studied to enable a tailored information for future end-users, to increase the demand for NZEB and beyond NZEB buildings and to improve their acceptability. To facilitate the living in NZEBs a guide for end-users was developed, explaining the "Myths" about NZEBs as well as presenting testimonials of current NZEB users in four participating countries. The paper presents the findings on end-users' experiences and expectations about living in multi-family Nearly Zero-Energy Buildings (NZEBs). The survey in four European countries (Slovenia, Italy, Denmark and Germany) was part of EU Horizon 2020 project CoNZEBs (2017-2019) and addressed end-users living or thinking about living in multi-family NZEBs. Targeted end-users were living (as tenants or owners) in either ordinary buildings or in high performance buildings such as NZEBs (mandatory after 2020 according to Directive 2010/31/EU). In the survey, the following topics were addressed: the level of end-user's understanding of the NZEB concept, the source and quality of information on NZEB from the end-users' perspective, the importance of various apartment features for the end-users, perception of NZEB characterizing technologies, and decision triggers for living in NZEB. Concerns, doubts and eventual fears about living in NZEBs were studied to enable a tailored information for future end-users, to increase the demand for NZEB and beyond NZEB buildings and to improve their acceptability. To facilitate the living in NZEBs a guide for end-users was developed, explaining the "Myths" about NZEBs as well as presenting testimonials of current NZEB users in four participating countries.

Professionals engaged in the design of new or retrofit of existing school buildings currently struggle to find comprehensive guidelines for achieving healthy and energy-efficient school environments. Recently, two major and independent research projects aimed at improving indoor environmental quality and energy performance of school buildings in Europe have been completed: SINPHONIE and School of the Future. Their guidelines reflect the distinct priorities and limited scope of each project. This paper compares for the first time and, as far as possible, synthesizes these outputs to facilitate their use in practice and research. Overall, SINPHONIE is most useful in addressing indoor environmental quality of schools in terms of the physical, chemical and microbiological stressors that impact and potentially affect human health. It aims to influence the future development of policy and regulations. By contrast, School of the Future presents a broader design-oriented approach based on best practice in four European countries. For the most part they complement each other in their recommendations; however, this review highlights several areas that require further clarification and research including links between indoor environmental quality and cognitive performance, the consequent appropriate level for the designed ventilation rate, and the role of adaptive thermal comfort in schools.

In 2008 the German Ministry of Economic Affairs and Energy launched an initiative for new or retrofitted energy-efficient school buildings as focus area within their research programme “EnOB” (Energy Optimised Buildings). The initiative (www.eneff-schule.de) comprises three different energy levels: • Best practice schools with energy-efficient renovations above the requirements in the energy-saving ordinance • Three-liter-house schools with energy needs for heating, hot water and auxiliary below 34 kWh/m2year • Plus energy schools that produce more energy than they use in the annual balance Currently three different plus energy school buildings have been planned, realized and monitored within the initiative, two of them being renovations (Stuttgart and Rostock), the last one being a new school building (Hohen Neuendorf). The three energy concepts include rather different technologies to generate heat and to reduce the energy consumption of ventilation and lighting systems. This is partly due to the research initiative approach of “EnEff:Schule” that asks for testing innovative technologies. There is however a general tendency to: • Low U-values of the building envelope with about 0.11–0.15 W/m2K at the walls and roof, 0.10 W/m2K for new base plates and 0.20–0.34 W/m2K for renovated ground slabs and basement ceilings and 0.80 W/m2K for windows • Large PV areas to compensate for the remaining energy use, sometimes in combination with other technologies or systems that generate electricity • Mechanical ventilation systems with high heat recovery rates but in combination with natural ventilation • User-dependent control strategies for ventilation and heating • Use of daylight at both the window/solar shading side and the electrical lighting control The paper compares the different technologies used at the building envelope, the heating, ventilation and lighting systems, the calculated and measured energy consumptions and the building costs.

Germany possesses a long tradition in energy-saving construction and has continuously tightened the energy performance requirements and extended the balancing scope in its energy-saving ordinance. In the last few years, several buildings with energy concepts that have the aim of generating more energy than the building needs (if compared in an annual balance) have been designed, realized and monitored - so-called plus energy buildings. This article presents selected examples of the plus energy approach for both residential and non-residential buildings along with their key technologies and available research initiatives dealing with the issue. It also discusses the different possibilities for defining the notion of plus energy and points to ongoing further developments for additional building types and settlements.

The aim of the “School of the Future” project ( www.school-of-the-future.eu [1]), which receives funding within the EU's 7th Framework Programme, is to design, demonstrate, evaluate and communicate shining examples of how to reach the future high- performance building level. School buildings and their primary users, namely pupils - the next generation - are in the focus of the project. Both, the energy and indoor environment performance of 4 demonstration buildings in 4 European countries and climates are being greatly improved due to holistic retrofit of the building envelope, the service systems, the integration of renewables and building management systems. The results and the accompanying research and dissemination efforts to support other actors dealing with building retrofits are leading to a multiplied impact on other schools and on the residential sector, since the pupils will act as communicators to their families. The user behaviour and the awareness of energy efficiency and indoor environment are being improved due to tailored training sessions. Nearly zero emission or nearly zero energy buildings are main goals in various country roadmaps for 2020. The demonstration buildings of this project may not completely reach this level, though, as the aim of the FP7 call is cost efficiency and multiplication potential. The retrofit concepts, however, result in buildings with far lower energy consumption than achieved by regular retrofits and focus on high indoor environment quality - thus leading the way towards zero emission. They can be considered as schools of the future. Results from national examples of zero emission schools complete the information used for developing the deliverables such as guidelines, information tools, publications and a community at the EU BUILD UP portal. The project is based on a close connection between demonstration, research and industry which is being represented by the “Design Advice and Evaluation Group”. This group of research and industry partners meets twice at every demonstration building site in order to give advice to the local planning group like informing them about suitable up-to-date technologies.

Im Rahmen des Begleitforschungsvorhabens zur EnEff:Stadt-Forschungsinitiative des Bundesministeriums fur Wirtschaft und Technologie (BMWi) wurde vom Fraunhofer-Institut fur Bauphysik eine Softwarelosung entwickelt, die Stadtplaner und andere Akteure in diesem Bereich in den ersten Planungsphasen unterstutzt. Innerhalb des IEA ECBCS Annex 51 wurde in Zusammenarbeit mit internationalen Partnern hieraus ebenfalls eine englischsprachige Version mit landerabhangigen Rahmenbedingungen und Informationen erstellt. Die Software mit dem Namen “Energiekonzept-Berater fur Stadtquartiere“ (“District Energy Concept Adviser“) enthalt eine Sammlung von individuellen Hilfsinstrumenten fur die Planung. Das Herz der Software ist ein Tool, das ein Stadtquartier energetisch bewertet. Dazu werden Gebaudetypen und weitere vorkonfigurierte Systeme herangezogen, um eine einfache und schnelle Abbildung der Gebaude im Quartier zu ermoglichen. Dadurch benotigt der Anwender nur wenige Schritte, um das Energieeinsparpotenzial von verschiedenen Strategien aus dem Bereich der Gebaudehulle, der Anlagentechnik und zentralen Energieversorgungssystemen zu ermitteln. EnEff:Stadt – The District Energy Concept Adviser. Within the framework of the German research initiative EnEff:Stadt (launched by the German Federal Ministry for Economy and Technology), Fraunhofer Institute for Building Physics IBP has developed a computer programme to support actors in the field of urban planning during the first stages of planning energy-efficient district concepts. This programme was developed in collaboration with international partners from IEA ECBCS Annex 51 “Energy Efficient Communities“ and comprises a set of individual supporting tools. The very heart of the programme is a tool for the energy assessment of districts, which uses archetypes and other pre-set configurations to allow for a simple and quick data input mapping all the buildings in the district. Thus it takes the user just a few steps to identify the energy saving potential of various strategies in the areas of building construction, technical building systems, and centralized supply systems.

The aim of the "School of the Future" project (www.school-of-the-future.eu), which receives funding within the EU's 7th Framework Program, is to design, demonstrate, evaluate, and communicate shining examples of how to reach the future high-performance building level. School buildings, their owners, and their primary users, namely students, i.e., the next generation, are the focus of the project. The energy and indoor environment performance of four demonstration buildings in four European countries and climates have been significantly improved due to holistic retrofits of the building envelope, their service systems, and the integration of renewables and building management systems. It is anticipated that the results of the project and the associated research and dissemination efforts will support others dealing with building retrofits, and will thereby have a multiple impact on other schools and on the residential sector since the students will act as communicators to their families. Training sessions specifically tailored to their needs have improved user behavior and awareness of energy efficiency and indoor environment. The success is measured by how well the retrofits meet the following goals: - Reduction of the total energy use > factor of 3, verified through monitoring; - Reduction of the heating energy use > 75%, verified through monitoring. The improvement of the indoor environment quality (air, daylight, acoustic, thermal comfort) and the associated impact on the students' performance will be analyzed by short-term measurements and questionnaires. The work of the local integrated planning teams responsible for retrofitting the demonstration buildings at each city (Stuttgart, Germany; Cesena, Italy; Ballerup, Denmark; and Drammen, Norway) was mirrored by the Design Advice and Evaluation Group, which is comprised of all industry and research partners of the project. Highlights of the retrofit technologies applied in the four schools include: strongly improved thermal quality of the opaque building envelope components, triple-glazed windows (also in a listed building, i.e., a historic, heritage protected building), automatically controlled natural ventilation system based on CO2 sensors, co-generation unit, ground-coupled heat pump, sub-division of heating circuits, and heating and ventilation system operation adapted to the actual room use, roof-top mounted photovoltaic systems, LED lighting, removal of an external brick façade plus addition of insulation and new lightweight façade envelope, etc. This paper provides an introduction into the EU project. It includes all results and a comparison of the four demonstration buildings, as well as a more detailed description of the German demonstration project.

The project BESTFACADE, sponsored by the Energy Intelligent Europe programme of the European Union, and led by MCE-Anlagenbau, Austria, accumulated the state of the art of double skin facades (DSFs) in seven European countries (Austria, Belgium, France, Germany, Greece, Portugal and Sweden). Twenty-eight facades of different buildings in all partner countries of BESTFACADE have been analysed for the aspects, types of facade in different countries, DSFs in different climatic regions of Europe, existing simulations and measurements, thermal behaviour, indoor air quality, comfort, user acceptance, energy demand and consumptions, control strategies, integrated building technology, cost (investment, maintenance and operation), resource conservation, environmental impact, comparison to conventional glass facades (CGFs), integration of renewable energy sources into DSFs, as well as non-energy related issues, such as, acoustics, aesthetics, fire protection, moisture, corrosion, durability, maintenance an...

Mit dem EnEff:Stadt Energiekonzept-Berater für Stadtquartiere hat das Fraunhofer-Institut für Bauphysik ein aktuelles Softwarepaket entwickelt, das Stadtplaner, Umweltbeauftragte, Investoren und Wohnungsbaugesellschaften bei der Entwicklung eines energieeffizienten Stadtquartiers im Neubau oder als Sanierungsprojekt in den ersten Planungsphasen unterstützt. Die hier vorliegende Broschüre erläutert den besonderen Ansatz des Konzepts und zeigt die Vorteile der Software auf. Mit dem Energiekonzept-Berater können bereits zu einem frühen Zeitpunkt verlässliche Aussagen über die Energieeffizienz und Optimierungspotenziale von geplanten Stadtquartieren getroffen werden. Die Software schließt damit für alle Planer und Investoren eine wichtige Lücke: Sie ermöglicht erstmals die vergleichende Bewertung unterschiedlicher Energiekonzepte und Effizienzmaßnahmen, noch bevor die aufwändige Detailplanung und Projektierung einsetzt. Die Software umfasst eine Schnellprüfung zur qualifizierten Einschätzung des Energieverbrauchs von Stadtquartieren, zwei Info-Bibliotheken zu Effizienz-Technologien und Projektbeispielen sowie, als professionelles Planungshilfsmittel, ein Programm zur Modellierung und Bewertung der Energieeffizienz eines Stadtquartiers

This paper presents some first approaches for the national application of the nearly zero-energy building definition according to the Energy Performance of Buildings Directive by summarising the current plans of Germany, Denmark, Ireland and the Netherlands. As a contribution from a 5th country, the planned nationalenergy performance requirements of Switzerland for the phase from 2018 onwards were included. It was also analysed whether any of the countries will set specific requirements to the air-tightness of NZEBs and if there are specific requirements for ventilation techniques.

As the Energy Performance of Buitdings (EPB) regutations cannot cover atl possible kind of new technotogies, Member States have to devetop "principte of equivatence" procedures, in order to atlow the assessment of systems not covered by the standard catcutation procedures. This information paper discusses the overatl context and describes the approaches used in several countries

Case studies demonstrating energy-efficient renovation of educational buildings collected by the International Energy Agency (IEA) provide information on retrofit technologies, energy-saving approaches and ventilation strategies. Some general findings are presented here along with one case study, Egebjerg School in Denmark, which shows how natural ventilation can be incorporated into a refurbishment project.

Les etudes de cas reunies par l’Agence internationale de l’energie (AIE) autour de la renovation energetique des bâtiments scolaires constituent une source d’information sur les techniques de rehabilitation thermique, les strategies d’economie d’energie et les methodes de ventilation. On trouvera dans les paragraphes qui suivent quelques constatations generales, suivies d’une etude de cas (l’ecole Egebjerg, au Danemark) montrant comment integrer la ventilation naturelle dans un projet de renovation.

The energy efficient renovation of the Solitude-Gymnasium in Stuttgart is one of the 4 demonstration buildings within the EU 7FP project “School of the Future”. The secondary school with about 710 pupils consists of a typical configuration with a main building, a building of scientific classes, a big pavilion, a small pavilion and a gym, built between 1966 and 1975. The main building and the gym include flats for the caretakers. The total heated floor area of the buildings amounts to 8,924 m 2 . The exterior walls of the buildings are made of exposed concrete or brick. All buildings have flat concrete roofs that had no sufficient insulation before the retrofit. Most windows consisted of PVC-frames and double-glazing, but in some corridors and stairways single-glazed facades existed. The heating was generated centrally for all 4 buildings by two gas boilers that replaced an earlier system in 2004. Domestic hot water for the gym is generated by a heat exchanger based on the heating water. Ventilation systems without heat recovery existed for some indoor rooms, some rooms in the building of scientific classes and the gym. All 4 demonstration buildings in the School of the Future project have the same goals: • Reduction of the total energy use > factor 3, verified through monitoring • Reduction of the heating energy use > 75%, verified through monitoring • Improvement of the indoor environment quality (air, daylight, acoustic, thermal comfort) with impact on the pupils’ performance, analysed by short-term measurements and questionnaires The building envelope renovation measures at the school in Stuttgart included external thermal insulation systems and curtain wall facades with 14-18 cm polystyrene insulation, 16-22 cm of expanded polystyrene on the roofs and mostly triple-glazed windows. The new heating system is a co-generation plant in combination with the existing boilers. The ventilation of the classrooms is now realised by decentralised ventilation units with 80% heat recovery (main building) or by hybrid ventilation consisting of window opening supported by actuators at the upper part of the windows that are controlled by timers and manually by the teachers. CO2 visualisation systems show the teacher when window opening is necessary. The existing ventilation system in the building of scientific classes are improved by central heat recoveries of 80% - 90% efficiency. Also the lighting system was updated by T5 compact fluorescent lamps, electronic ballasts, daylight control and presence detectors. A one-year monitoring period will show whether the energy performance goals (reduction of final energy from 225 to 58 kWh/m 2 yr and primary energy from 215 to 54 kWh/m 2 yr) and the indoor comfort goals can be achieved.

The next level of energy performance of new buildings within the European Union will be the Nearly Zero-Energy Building (NZEB). A lot of work has been spent on pilot and demonstration buildings on this and also even higher energy performance levels throughout all EU countries. However, most of the high performance buildings realised so far result in higher investment costs when compared to the current national minimum energy performance requirements. The considerably higher investment costs are one of the main barriers to the early application of the NZEB-level in Europe. The EU H2020 project CoNZEBs works on technical solution sets that result in lower investment costs for NZEBs, bringing the costs close to those of conventional new buildings. The focus is on multi-family houses. In each of the four participating countries Germany, Denmark, Italy and Slovenia a team of researchers is analysing which sets of marketready technologies at the building envelope, the services systems for heating, domestic hot water, ventilation and cooling (where required) in combination with renewable energy systems can fulfil the NZEB requirements at lower costs than those incurred by the national mainstream NZEB application. Additional efforts are being spent on the life-cycle costs and the life-cycle analysis of the solution sets, as well as on the impact of future developments of primary energy factors, energy costs and technology efficiencies.

Nearly zero energy buildings (NZEBs) are required as the minimum standard for all new buildings in Europe by January 2021. NZEBS should, according to the Energy Performance of Buildings Directive (EPBD) [1], be cost optimal, i.e. the cost of constructing and operating the building over its lifetime should be at its minimum. The EU Horizon2020 research project CoNZEBs, identify and assess technology solution sets that lead to cost reductions of new NZEBs in four EU member states. Focussing on buildings that comply with national NZEB requirements, designers can easily ignore alternative solutions that make the building cheaper while remaining within national requirements. This is not done intentionally, but primarily due to use of a traditional design thinking where optimisation is done on component level instead of a more holistic approach. Changing one building component may influence the cost and performance of other components. These alternative solutions take offset in a typical national multi-family building design and analyses the different lifetime costs in terms of costs for construction, and energy. Analyses of costs in different countries reveals different solutions sets being optimal. In CoNZEBs we compare different solution sets and investigate the possibility for “exporting” solution sets from one country to another.