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This paper presents the methodology for conducting a cost-optimal energy performance calculation of a solar hot water system, used for space heating and domestic hot water needs. The calculation is based on dynamic hourly methods, according to the new Energy Performance of Buildings’ (EPB) set of standards EN 15316:2017, and a revision of the standard EN 15316-5:2017 from the year 2021, dealing with storage-tank water temperature calculations. The paper provides proposals for modifications to these newly introduced standards, in order to overcome the observed ambiguities and shortcomings. The calculation of annual energy performance of a building was performed on an hourly basis over a year for the reference of an nZEB multi-apartment building, for a climate area of the city of Zagreb, taking into account water temperature change in the layers of the storage tank connected to solar collectors and hot water boilers. The cost-optimal solution was then determined by varying individual parameters of the building technical system. The influence of these parameters on the energy efficiency of the building was analyzed in detail. Furthermore, the results were compared against those obtained by the Croatian calculation algorithm based on the previous set of EPB standards, EN 15316:2008, currently used EU-wide for the energy performance certification of buildings. The results indicated that the calculation methods of the present algorithm underestimated the consumption of building primary energy by 12%. The energy delivered by solar collectors was underestimated by 18%.

In Europe, buildings are responsible for more than one third of the total final energy demands and greenhouse gas emissions. In the last twenty years, the European Union has published a succession of energy performance of building directives to define and ensure the fulfilment of a series of objectives regarding greenhouse gas emissions, energy consumption, energy efficiency and energy generation from renewable sources in buildings. For its part, Spain is adapting its legal framework, transposing these directives with the aim of achieving greater energy efficiency and sustainability for buildings. Under this context, an energy, economic and environmental assessment is performed to analyze the impact of these regulatory changes on a single-family home including a photovoltaic installation for self-consumption with surpluses and/or a solar thermal installation for domestic hot water supply, located in each one of the eight thousand one hundred thirty-one municipalities that make up Spain. The energy behavior of the original house is compared with that obtained after it is updated with these new facilities. The transient system simulation tool is used for the energy study. The results show that the European objectives are far exceeded. The energy savings achieved range from 67% to 126%, carbon dioxide emissions decrease by 42% to 100% and energy bills are reduced in cost by 32% to 81%. The findings of this work can be used by policymakers as guidelines for the development of national strategic plans and financial incentives for the promotion of small-scale residential photovoltaic and solar thermal applications, as well as by designers, supervisors, managers and developers to include them in their projects.

BUILD UPON2 project proposes to work with local, national and European stakeholders to create a Multi-Level Renovation Impact Framework that contains a suite of milestones and measurable progress indicators for building renovation strategies. This Framework will serve as tool for Cities in delivering the EPBD and ensure that local initiatives are aligned with national and European policies. The objective of the project’s Italian cluster is to gather together a number of cities and stakeholders aiming at sharing strategies and results of initiatives undertaken at city scale for the renovation of the building stock and testing the Multi-Level Renovation Impact Framework.

The effective design of nearly zero-energy buildings depends on a large set of interdependent variables, which affect both energy demand and supply. Considering them simultaneously is fundamental when searching for optimal design of nearly zero-energy buildings, as encouraged by the EU in the second recast of the Energy Performance of Building Directive (EPBD). This paper presents the application of the new energy demand and supply simultaneous optimization (EDeSSOpt) methodology to optimize the design of a single-family house in the Italian context. Both primary energy optimization and financial optimization are carried out in the context of European regulations. Robustness of the resulting optimal solution is studied through analysis of optimum neighborhoods. The resulting cost-optimized solution relies on a moderately insulated envelope, a highly efficient system, and 34% of coverage from renewables. The energy-optimized solution requires a higher level of insulation and a higher coverage from renewables, demonstrating that there is still a gap between energy and cost optimums. Beyond the results, integrated optimization by means of EDeSSOpt is demonstrated to better minimize cost functions while improving the robustness of results.

In the EU’s revised Energy Performance of Buildings Directive (EPBD), a smart readiness indicator (SRI) was introduced as an energy efficiency activity to promote smart ready technologies (SRT) in the building sector. The proposed methodology is based on the evaluation of building services and how they contribute on SRT. The purpose of this paper is to explore the applicability of the SRI to cold climate countries in Northern Europe. The Northern European countries are an interesting test environment for the indicator because of their advanced information and communication technology and high building energy consumption profiles. The findings imply that regardless of the SRI’s conceptualization as a system oriented (smart grid) approach, in its current form, it was not able to recognize the specific features of cold climate buildings, specifically those employing advanced district heating (DH) systems. Another, more practical, implication of the study was that due to the subjective nature of the proposed process for selecting SRI relevant building services, the applicability of SRI as a fair rating system across the EU member states is problematic.

Nearly Zero Energy Buildings (nZEB) are a significant part of the energy efficiency strategy of the European Union. As buildings represent approximately 40% of the final energy use in Europe, the reduction of their energy demand is key for a sustainable future. This paper takes a qualitative approach and presents data about professional and market barriers, as well as the educational market in relation to the implementation of nZEB policies for new and retrofit buildings in 11 European countries. Different levels of policy enactments and market penetration are reported and are generally found to be more advanced in western and central European countries. Furthermore, gender equality is examined in the building sector in relation to nZEB and presents significant gaps, with a more balanced situation reported in southern Europe. The accreditation and targeted education of nZEB experts is still almost non-existent in the examined countries, and the need for training of building professionals is highlighted as a critical missing component of current policy. This research aims to be the first step towards the creation of educational material and programmes as a mean to accelerate the transition to nZEB.

At the end of November 2016, the European Commission tabled the Clean Energy for All Europeans package, which represents a large set of proposals for several key directives related to energy. The package included proposed revisions to the Energy Performance of Buildings Directive (EPBD) which seek to update and streamline the Directive in several areas, including provisions to ensure buildings operate efficiently by encouraging the uptake of Information and Communication Technologies (ICT) and smart technologies. Although it can be argued that there is at present no commonly accepted definition of a “smart building”, the Commission’s proposed revision refers to three key features of a possible indicator of “smartness” in buildings: the technological readiness of a building to (1) interact with its occupants; (2) to interact with the grid; and (3) to manage itself efficiently. Using these three pillars of “smartness” as a methodological starting point, this paper identifies and analyses recent and ongoing Horizon 2020 research, innovation and market uptake projects which are investigating “smart buildings”. The research maps and examines the tasks, scope and innovations in areas that include building automation and control systems, demand response, energy management, ICT and user interfaces for energy efficiency.