How is nZEB standard achieved and how designing nZEB buildings differs from the usual practice? Can the adoption of nZEB legislation at the national level be sufficient for its successful implementation?
Architects, civil engineers and mechanical engineers, as well as all other participants in construction projects, have in recent years been faced with numerous changes of legislation related to energy efficiency, energy classes and their calculation. Shortly after the introduction of the EPBD (Directive on the energy performance of buildings), followed by a much more demanding obligations, according to which each Member State shall by the end of 2020 define the minimum number of nZEB buildings (eng. Nearly Zero Energy Buildings) in the total number of buildings. During the introduction of the EPBD, at the conference Climate Neutral Cities in Geneva, experts concluded that energy classes listed in the 2002 Directive are not enough to guarantee the quality and control of high-energy buildings, or nZEB buildings. This was confirmed in mid-2014, when the European Commission reported that the majority of Member States have not done enough for the successful implementation nZEB’s by 2020. Specifically, each Member State is allowed to independently define nZEB and then determine at a national level.
Passivhaus and nZEB
Many developed countries, such as Belgium, Austria or Germany , which have started to implement the EPBD directive significantly before Croatia or Greece or Italy, and in terms of technical conditions have already determined nZEB standard that is identical or very similar to the Passive House standard (further: Passivhaus standard). This approach prevents unnecessary waste of time and “reinventing the wheel” and represents a good example to countries that in the short term must meet the requirements of the European Commission. Passivhaus standard is based on immutable physical principles, while the concept is based on the comfort ( hygenic) conditions of interior space that each user should enjoy. It is thus not surprising that some of the states relied on the Passivhaus standard in determining and implementing the nZEB directive.
What stands out in most of the media dedicated to low energy buildings, but also among building professionals, are numerically expressed criteria, while the functional definition is emphasized rarely. Consequently, no wonder that most architects are poorly interested in designing according to the Passivhaus standard, and most of the investors and users are skeptical, since numerical values (Passivhaus criteria) are still being disconnected from the awareness on functional advantages of Passivhaus buildings.
In the media Passivhaus buildings are often described by listings of technical equipment, by selection of buildings’ components, by energy savings achieved. Improving the energy performance of building elements or the introduction of more efficient mechanical systems significantly contribute to achieving Passivhaus standards. But these are all just parts that do not guarantee the benefits of the whole, and only by unifying them throughout design approach ensures favorable harmony of all components of the building.
It is well known that it is difficult to visualize the numerical definition in architecture without proper knowledge of the cause-effect relationship between technical and functional characteristics of a building. Unsurprisingly, there are prejudices among investors, users and professionals, related to the limited freedom of architectural expression, or prejudice on limited freedom of the user behavior. When referring to „Passivhaus“, architects often refer only the mechanical features and building’s components with improved properties, while the integrated approach that achieves the best design solutions in accordance with the energy efficiency and comfort of the building are often being neglected.
Vocational education and training
National development of high-tech buildings in compliance with the nZEB directive will certainly not be possible to achieve only by the legislation definition that will numerically describe nZEB standard. It is the education of all participants in the design process that is needed. Just as the implementation of the EPBD regulations entail additional vocational training for jobs in energy certification, additional professional basis for the implementation of more demanding nZEB directive is a must.
The detected need for further vocational training that is essentially required for nZEB buildings development, required for building professionals’ integrated design approach, encouraged the proposal of European SEEDpass project (South East Europe strategic partnership in vocational education and training and Passive House Design for nearly zero energy buildings development). In duration of two years, SEEDpass aims to create educational and regionally adapted materials (adapted to climate conditions and to building practice) for architects, civil engineers and mechanical engineers. This is an essential base needed for a successful application of nZEB directive, and thus also for designing to Passivhaus standard. Synergy of the international Consortium should ensure and provide quality implementation of the project according to the comparative results of scientific and field research.