2.I.iii. Action plan for progression to NZEB for new buildings – OVERVIEW

The first draft of the Austrian national plan on increasing the number of NZEB by 2020 was published in 2012 for residential buildings and 2014 for non-residential buildings, according to OIB³. A revision of the national plan took place in 2018. This document was agreed by all nine (9) federal provinces and their requirements will be implemented in the regional building regulations successively until January 2021.

The NZEB is defined as an energy-efficient building with a thermally well-insulated envelope and an efficient heating system.

The minimum requirements for the energy performance of NZEB are shown in Tables 6-7.

Compliance with the requirements of the OIB Guideline 6 can be achieved by two methods:

• Through the provision of the maximum permissible space heating demand and final energy demand of the building. In this case the focus lies on the insurance of a tight building envelope in order to reduce the space heating demand (HWB) (not considering the f_GEE factor).
• Through the installation of a very efficient or renewable heating system. In this case the total energy efficiency factor (f_GEE) has to be taken into account, which reflects the type of energy use and production. In this method, a slightly higher space heating demand of the building is acceptable.

In both cases, the maximal values for the non-renewable primary energy demand are defined.

Table 6. Minimum energy performance requirements for new residential NZEB.

Table 7. Minimum energy performance requirements for new non-residential NZEB.

Figures and statistics on existing NZEB

In the past 20 years, considerable efforts have been made to reduce energy consumption in the building sector. Implementing new building regulations for the energy demand of buildings and providing subsidies for energy efficiency measures in new buildings and renovations are considered the engine for implementing energy efficiency. This has contributed to the increase in the number of buildings with low energy consumption. The following are best-practice examples of built NZEB in Austria.

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In the Brussels-Capital Region, the NZEB obligation implemented to comply with Article 9 of Directive 2010/31/EU has been integrated into COBRACE and will make NZEB obligatory by 2021. The new office and teaching buildings (public or not) had to be NZEB as of 2019.

The Brussels-Capital Region has set up ambitious energy standards for new constructions, which were applied starting in 2015. These standards target nearly zero or very low energy consumption and are inspired by the passive standard, where high-energy performance is first achieved similarly to the NZEB requirements. These standards are presented in Table 2.

For residential units, the 2015 EPBD requirements are very ambitious for an urban context and comply with the nearly zero-emission objective. The energy losses are in fact reduced to their minimum (from a cost-optimal perspective) and the need for compensation by renewable energy is implied by the requirement to fulfil the maximum primary energy consumption requirement (45 kWh/m².year); however, the specific RES share is not quantified.

Since 2012, the Flemish NZEB action plan focuses on informing, educating, facilitating and financially aiding local authorities and the public, as well as public, professional, financial and commercial organisations with the introduction of NZEB in the different domains of society by involving them in over 30 actions and projects^7,8.

An important action consists of clearly defining and communicating NZEB regulations and supporting NZEB frontrunners by providing financial grants. The NZEB-levels are defined by the cost-optimal studies that comply with the methodological framework provided by the European Commission⁹. The cost-optimal studies on residential and non-residential buildings resulted in the following levels of the energy performance indicator (E-level)¹⁰:

1. for residential buildings: E35 in 2020, E30 (= NZEB level) in 2021;
2. for non-residential buildings: see Table 1 (NZEB levels are mentioned in the last column);
3. for public authority buildings: see Table 2 (NZEB levels are mentioned in the last column).

Table 1. E-level tightening scheme for non-residential buildings.

Table 2. E-level tightening scheme for public administration buildings.

Apart from the E-level, the NZEB definition for new buildings includes additional requirements such as a minimal share of RES.

In general, with NZEB becoming the norm as of 2021, continuous actions focus on providing builders, contractors, architects and local authorities with educational information on all the aspects that need to be taken into consideration when constructing NZEB. Educational institutions updated their curricula by integrating the know-how that is required for working on NZEB. The aim is to enhance knowledge and therefore improve the quality of the work.

Specific tools aimed to the public are the NZEB-label (Figure 5), a NZEB-handbook (Figures 6 to 8), and the website www.BEN-architect.be where one can search for existing NZEB projects and training. The BEN-architect website holds a catalogue of 217 residential, public, office and commercial buildings, and provides details on the designer, the energy performance, the applied techniques and insulations (Figures 9 to 11). During building fairs, these tools are actively promoted to the public. The NZEB-handbook and BEN-architect website are popular. Contractors and suppliers of (innovative) building products keep on registering so they can use the NZEB-frontrunners label.

Figure 5. Branding the NZEB-label, available for NZEB frontrunners.

Figure 6. NZEB-handbook: cover.

Figure 7. NZEB-handbook: NZEB requirements.

Figure 8. NZEB-handbook: guidelines for design and execution.

Figure 9. NZEB website with 217 nearly zero-energy residential, office, commercial and public buildings, providing energy performance details, information on material, installations, NZEB architects and NZEB training.

Figure 10. Zero-energy office, bank office in Gooik: E-level 1, K-level 25.

Figure 11. Energy performance details on www.BEN-architect.be of the office building in Figure 10: E-level 1, K-level 25.

Regarding future professionals, NZEB actions are a collaboration with the professional associations and cover quality control, including education (competences and knowledge), execution (study as well as execution on the building site), and definition of regulations for good practice (ventilation, airtightness and RES installations). These projects are executed in close collaboration with the Department of Education, educational institutions and the professional federations of architects, contractors and energy experts.

For the local authorities, a region-wide roadshow of good examples (one in each of the five provinces, with diverse functions, e.g. schools, small and big office buildings, public buildings, kindergarten) was set up in 2015-2016 to enhance their NZEB knowledge and motivation. The roadshow was hosted by the mayors, members of the city council and the building teams (Figures 12 to 15) who presented their NZEB project:

• General explanation of NZEB-requirements
• Technical comment by architect
• Information on the user experiences and motivation of the choice to realise NZEB
• Guided tour
• Q&A and interaction

A total of 147 participants were registered. A guide with a description of the legal and policy context and including ample descriptions of the five (5) good practices was prepared, distributed and made available on websites.

During an 18-month period, the local governments could apply for free assistance and NZEB advice and guidance in the building process to set up their own NZEB building projects. Thirty-one (31) local authorities benefited from this offer.

Figure 12. A good example for local governments: a nearly zero-energy after-school day-care centre: (source: BEN-guide for local governments).

Figure 13. A good example for local governments: a nearly zero-energy after-school day-care centre: energy performance (source: BEN-guide for local governments).

Figure 14. A good example for local governments: a nearly zero-energy after-school day-care centre: materials and installations (source: BEN-guide for local governments).

Figure 15. A good example for local governments: a nearly zero-energy after-school day-care centre: materials and installations (source: BEN-guide for local governments).

NZEB requirements are based on the results of calculations on model geometry, statistical data and subsidy databases⁴. These new requirements were approved by the regional stakeholders of the building sector and adopted by the government on 28 January 2016⁵. They are presented in Table 2.

If Wallonia does not set intermediate targets in terms of the share of new NZEB buildings before 2021, it has nevertheless:

• set up two calls for projects for Wallonian exemplary buildings addressed respectively to residential and non-residential buildings, in order to prepare the building sector and citizens for future NZEB requirements. This action covers new buildings as well as the renovation of residential and non-residential buildings. Actual achievements are highlighted on the energy portal site but also in the print and audio-visual media (partnerships with the broadcast 'Une brique dans le ventre' and 'Clé sur porte' on the two main French-speaking television channels in Belgium);
• organised seminars with the Union of Towns and Municipalities of Wallonia (Union des Villes et Communes de Wallonie) to inform the municipalities of changes to the regulations (NZEB requirements, certification of public buildings, control of regulations related to planning permission, etc.).

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Based on requirements for NZEB (see requirements in Tables 1 & 2), 5,719 residential buildings and 236 non-residential buildings included in the EPB database already meet the definition of NZEB, representing 11.6% and 18.2% respectively of total final EPB statements. All these building units were actually built by the end of 2019.

For residential buildings, the renewable solutions most commonly used to meet the NZEB requirements include the use of a combination of a heat pump and PV (22.6%), a heat pump (20.3%) and PV (15.7%). It is interesting to observe that, in 29.3% of cases, the net energy needs for heating and overheating set out in the NZEB requirements for primary energy consumption are met without the use of any RES system (Figure 1).

For non-residential buildings, the RES solutions most commonly used to meet the NZEB requirements include the use of a heat pump (36.0%), a combination of a heat pump and PV (15.7%) and PV (12.7%), while 34.8% meet the requirements without the use of any RES system (Figure 2).

Figure 1. The number of residential built NZEB units and use of RES by the end of 2019.

Figure 2. The number of non-residential built NZEB units and use of RES by the end of 2019.

The National Plan for Nearly Zero-Energy Buildings 2015-2020 was adopted by the Council of Ministers in December 2015. The plan contains:

1. the national definition and the technical parameters of NZEB, reflecting the national conditions;

2. the national targets for increasing the number of NZEB depending on the classification of the types of buildings;

3. policies and mechanisms, including those of a financial nature, to stimulate the construction of NZEB.

The definition of NZEB is given in the Energy Efficiency Act of 15 May 2015. A NZEB is a building that simultaneously fulfils the following conditions:

1. the energy consumption of the building, defined as primary energy, complies with Class A on the scale of energy consumption classes for buildings of the relevant type; and

2. not less than 55% of the energy consumed (supplied) for heating, cooling, ventilation, domestic hot water and lighting is energy from RES produced on-site or near the building.

National targets for the construction of new buildings that satisfy the definition of the NZEB are given in Table 1. These targets are categorised according to the groups of buildings and estimated cumulative figures of end-use energy savings and emission reductions as of 2020 are provided.

Table 1: National targets for constructing new NZEB by 2020

The intermediate annual targets for improving the energy performance of new administrative buildings which include buildings occupied and owned by public authorities to satisfy the NZEB definition are given in Table 2. This table also includes estimated cumulative figures of end-use energy savings and emission reductions.

Table 2: National targets for constructing new administrative NZEB by 2020.

The Research Centre of the Technical University of Sofia, built in 2012, was the first NZEB in Bulgaria. The total primary energy use is 47.94 KWh/m² per year.

Figure 1: The first NZEB in Bulgaria, the Research Centre of the Technical University of Sofia.

The primary energy requirements for NZEB were established in 2014 as the lowest primary energy values among the analysed systems, providing they do not correspond to high overall costs. The lowest-cost measures have been determined using the cost-optimal analysis, thus setting the optimal level of energy consumption for new and refurbished buildings. In contrast, when determining the requirements for NZEB, the range of options with the lowest primary energy consumption have been chosen in order to set requirements within the cost-effective range (primary energy below cost-optimal level, and the global cost below the existing building global cost reference). 

At least 30% of the annual primary energy must be covered using RES generated on-site (i.e., on the building or in its immediate vicinity); requirements for Q _H,nd and U-values for building elements are also applied as for new buildings.

NZEB definitions were set in 2014 for all types of buildings and have recently been updated in the technical regulation of 2015. Values for maximum allowed E"_prim for some types of buildings (according to the regulations from 2014) have slightly increased due to the variety of the reference geometry input when analysing cost-optimality and NZEB. In situations where energy use values in kWh/m² for NZEB were higher than the values obtained in the cost-optimal analysis, the values for NZEB were corrected according to the results of the geometry for the cost-optimal analysis. The number of new low-energy and passive buildings increases in Croatia on a yearly basis, particularly for single-family houses, multi-residential buildings and recently constructed office buildings. As of 31 December 2019, all new buildings must be designed as NZEB.

The national action plan for increasing the number of NZEB, which was issued in 2012 and revised in 2016, identifies a number of actions to be taken up to 2020. The first step towards NZEB is considered to be the issuance of the 'Requirements and Technical Characteristics of the NZEB Ministerial Order of 2014 (Κ.Δ.Π. 366/2014)'. The order provides, in a legally binding document, the requirements that will be set for new buildings by 2020, as well as a high energy efficiency standard that can voluntarily be implemented in new and renovated buildings before 2020. The requirements for NZEB specify low U-values, maximum heating demand for residential buildings, maximum lighting power installation for office buildings, maximum primary energy consumption and a minimum contribution of RES. The requirements differ only between residential and non-residential buildings, but the same requirements apply for new and existing buildings.

In order to assist building designers in the design of NZEB, the MECI issued 'The Technical Guide for NZEB' in 2015, which documents how architectural design, building envelope, technical building systems and RES can be optimally combined.

A revision of Κ.Δ.Π. 366/2014 is scheduled to be set in force in 2020. The aim of the revision is to reflect stakeholders' views during public consultation of new minimum energy performance requirements, mentioned above, as well as technical progress in buildings.

The Energy Management Act No. 406/2000 Coll. defines the NZEB as a building with very low energy performance whose energy consumption is to a very significant extent covered by RES. The exact proportion of energy that should come from RES is not defined. Several conditions must be fulfilled by the builder/designer for the building to be categorised as NZEB. Energy indicators to be met for a building to be considered NZEB are the same for new buildings. However, in the case of NZEB, the Czech legislation demands a gradual decreasing of the primary energy for the reference building. The assessed building must meet this stricter requirement either by increasing the share of RES or by improving the building envelope. The NZEB must then meet the reduced value requirement for primary energy, reduced by 25% for family houses, 20% for apartment buildings, and 10% for other buildings. After 1 January 2022, this NZEB requirement will be even stricter and range from 20% to 60% depending on the energy reference area and the heat demand. The legislation consists of a two-step requirements approach: the cost-optimal level requirements, which came into force on 1 April 2013, and the gradual tightening of requirements towards NZEB depending on the size and type of the building, which gradually came into force between 1 January 2016 and 1 January 2020. The amendment of Decree No. 264/2020 Coll. introduced stricter values for the reference building which indirectly impacts NZEB levels. The amendment also introduces stricter requirements for NZEB (see above) as such for newly constructed buildings (so-called NZEB after 1 January 2022) in order to better reflect the real meaning of NZEB.

Examples of newly constructed highly efficient buildings in the Czech Republic

LUKA LIVING RENTAL APARTMENTS & SHOPPING CENTER

Luka Living is an original and revolutionary project of the 21^st century, located in Prague, providing modern rental housing with hotel services within fully equipped apartments with a low-energy standard. Luka Living offers 215 apartments ranging from studios to exceptional fully furnished apartments. The entire complex includes 7,000 m² of retail space within the surrounding area. The complex includes a grocery store, pharmacy, drugstore, bank, restaurant, fitness centre, laundry, hairdresser, tobacconist and children's playground.

Figure 2: Luka Living rental apartments & shopping center.

Table 2: Parameters of the Luka Living rental apartments & shopping center.

ELEMENTARY SCHOOL PSÁRY

A newly constructed passive standard elementary school and gymnasium, located in the Central Bohemia Region. The cover is made of sand-lime brick and reinforced concrete with approx. 240 mm of mineral insulation of U-value 0.14-0.19 W/(m².K). The floor includes 180 mm of EPS insulation with a U-value of 0.17 W/(m².K), while roofs are inclined and flat with different insulation thicknesses and a U-value between 0.13 and 0.18 W/(m².K). Windows include triple glazing and have U_w = 0.75 W/(m².K). External shading with automatic and manual control is connected to the central control.

Heating is provided primarily by a cascade of four heat pumps (4x31 kW) and a set of two condensing boilers of 50 kW each (floor heating, radiators, hot-air heating). Forced ventilation with recuperation, an advanced control and regulation system (CO₂ sensors, humidity, time mode) and optimised flow rates are applied throughout the building through a total of 10 air ventilation units. Cooling is provided only for the kitchen space through compressor units. There is a LED lighting system with intelligent control.

Figure 3: Elementary school Psáry.

Table 3: Parameters of elementary school Psáry.

Denmark has revised its definition of NZEB following the analysis of the cost-optimal calculations and the Commission's interpretation of when a building should be an NZEB. Denmark has historically used the date of the building permit to decide which requirement should be fulfilled. The Commission interprets the EPBD in a different way and defines the requirement to be for the finished buildings. In line with this, Denmark needed to revise the Danish definition of NZEB.

All new buildings applying for a building permit after 1 July 2016 therefore comply with the NZEB requirements¹.

The current energy performance legislation includes the definition of low-energy buildings and NZEB buildings. A low-energy building is a building that is characterised by sound engineering solutions, considering the current best practices without the on-site renewable electricity production, and which meets the set primary energy performance requirements (Table 2). An NZEB is a building that is characterised by sound engineering solutions, considering the current best practices, but including on-site energy production by RES (the share of energy by RES is not fixed) and which also meets the set primary energy performance requirements (Table 2). Requirements for the low-energy building and the NZEB are fully based on the primary energy indicator. There are no component-based requirements.

All public buildings that apply for a building permit after 31 December 2018 must be NZEB. All buildings (except for small residential buildings, see Table 2) that apply for a building permit after 31 December 2019 must be NZEB.

In 2012, the Ministry of the Environment launched an intensive process to gather the necessary input for the preparation of the national plan for NZEB. Based on this process the national plan for increasing the number of NZEBs was drawn up and submitted to the European Commission in October 2012. The aim was to give technical recommendations for NZEBs in 2015.

As the Land Use and Building Act sets the base for the building code, the changes to NZEB requirements were made in autumn 2016 and the revision of the Land Use and Building Act came into force on 1 January 2017. Based on regulations given by the Ministry of the Environment, the new National Building Code is applying to new buildings since 1 January 2018.

Finland has long encouraged energy-efficient construction, and there are many examples of energy-efficient single-family homes, apartment buildings, day care centres and shopping centres (Figure 1). As the new regulations for new buildings came into force on 1 January 2018, the share of, for e.g., new single-family homes in energy efficiency classes A and B have risen to 96 % (based on energy performance certificates issued in 2018 and 2019). (Energiatodistusrekisteri.fi).

Figure 1: Luhtaa Day Care Centre in Tampere represents energy efficient modern construction.

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In France, the label ‘Low Consumption Energy Buildings’ (Bâtiments Basse Consommation - BBC) is used to describe buildings with very low energy consumption (NZEB), and in the case of individual residences also includes a great proportion of RES. Since 2013, all new buildings, including public buildings are mandatorily NZEB, since requirements for Low Consumption Energy Buildings are the same as in RT 2012. Therefore, the cost-optimal level for NZEB has been evaluated along with the RT 2012 one. The future regulation, based on the feedback from the E+C- testing scheme will bring energy performance for new buildings one step further. 

The new regulation in preparation is about to seek energy performance but also aims to reach ambitious carbon emission reduction. Predicted to be released in January 2021, the regulation will be named RE2020 (for Environmental Regulation of 2020).

With the strengthening of the new building requirements valid from 1 January 2016, Germany made a decision on the NZEB level. Compared to the former performance values, the maximum primary energy demand was reduced by 25%, as were the requirements to limit the heat transfer, which were reduced by an average of 20%. This level was identified as cost-optimal.

The Energy Saving Act¹⁴ was amended in 2013 with a verbal description of the NZEB (in accordance with the EPBD) and the obligation to comply with this level, applicable to new buildings owned and occupied by public authorities by 1 January 2019 and to all other new buildings by 1 January 2021. Furthermore, the act obliges the government to specify the NZEB level for new public buildings in an ordinance issued before 2017, and for all other buildings in another ordinance issued before 2019.

The national plan for increasing the number of NZEB (according to Directive 2010/31/EU, Article 9) was approved in December 2018 with Ministerial Decision YPEN/DEPEA/85251/242 (GoG B’ 5447/5.12.2018). The national plan:

• defines the technical characteristics of buildings with almost zero-energy consumption, taking into account national, regional or local conditions, and including a numerical indicator of primary energy use in kWh/m² year;
• sets intermediate targets for improving the energy efficiency of new buildings;
• provides information on the policies and financial or other measures taken to promote NZEB, including details of national requirements and measures concerning the use of energy from RES in new buildings and existing buildings which undergo major renovation.

It also provides:

• the characteristics of the national building stock;
• the evolution, through time, of the national requirements related to the energy performance of buildings;
• the energy characteristics of the buildings with nearly zero-energy consumption;
• policies and measures to encourage improvements in the energy efficiency of buildings so as to meet the requirement that from 1 January 2021 all new buildings are to be NZEB;
• policies and measures to transform existing buildings through deep renovation to NZEB.

An update of the national plan for increasing the number of NZEBs is expected to be adopted in 2020.

Since 2016, new energy labels have been introduced in the certification scheme: 'BB' means NZEB, and there are three even more ambitious levels. The NZEB requirements become obligatory after 2019 -2020.

The national plan on NZEB was adopted in 2015 by the Prime Minister’s Office. It contains the NZEB requirements that were later transposed by the national rulebook on the energy efficiency of buildings (Decree 7/2006). It envisages initiatives on the improvement of energy efficiency of the existing building stock, but also on renewable energy systems that can be applied in new buildings. Since 1 January 2017, a new system to support the use of renewables is valid in Hungary, which is called 'Renewable support system' (METÁR)⁹. It is a new support system for the produced electricity in Hungary. By using this system, Hungary should fulfil the previously agreed share of 14,65% renewable energy¹⁰. The potential applications of the use of renewables will be supported by public funds, and new subsidy programmes will be available.

Focusing only on the NZEB requirements, the structure of the regulation (Decree 7/2006.) is the following:

1. Elements: maximum U values for walls, windows etc. (Table 3).
2. Building envelope: maximum limits for the specific heat loss coefficient (W/m³K), depending on the surface to volume ratio. This coefficient takes into account the transmission losses as well as the passive solar gains (through which indirectly the effect of thermal mass); thus data depending only on the building itself (Figure 3).
3. Thresholds for the specific yearly primary energy consumption (Figures 2-4).
4. Minimum of 'renewable share', which is set at 25%. Where the share of renewable energy cannot be reasonably (technically, economically or environmentally) met, legislation allows the builder to replace it by meeting an increased cost-effectiveness requirement.
5. Additional requirements.

There are requirements on balancing, control, pumps, airtightness of ventilation ducts, but these requirements are relatively low. Directive 2009/125/EC on EcoDesign requirements for energy-related products (ErP directive)¹¹ has a more significant impact on technical building systems.

Figure 1. The specific heat loss coefficient [W/m³K] after 2006.

The basic requirement level was in force until the end of 2017. The cost-optimal requirements were introduced in 2015 and used firstly for buildings receiving public funding. The NZEB requirement for the specific heat loss coefficient is identical to the cost-optimal requirement except for lightweight structure buildings.

Figure 2. Requirements for the specific yearly primary energy need of residential buildings.
(Basic: from 2006, Cost optimal: from 2018 (in some cases 2015), NZEB from 2019.

Figure 3. Requirements for the specific yearly primary energy need of office buildings.
(Basic: from 2006, Cost optimal: from 2018 (in some cases 2015), NZEB from 2019.

Figure 4. Requirements for the specific yearly primary energy need of educational buildings.
(Basic: from 2006, Cost optimal: from 2018 (in some cases 2015), NZEB from 2019.

The Building Regulations for new residential buildings were last updated in 2019. Approximately 6% of all new and existing residential buildings achieve the NZEB standard, as shown in Table 5. Ninety-seven percent (97%) of the 50,706 new homes built in the 2015-2020 period may be considered NZEB.

Table 5: Number of residential buildings at NZEB standard.

The Building Regulations for new buildings other than dwellings (non-residential) were updated in 2017. Approximately 1% of all new and existing non-residential buildings achieve the NZEB standard, as shown in Table 6. Twenty-one percent (21%) of the 1,623 new non-residential buildings built in the 2015-2020 period may be considered NZEB. The Building Regulations for residential buildings were updated in 2005, 2008, 2011 and 2019. RES is mandatory for residential buildings from 2008 onwards. The Building Regulations for non-residential buildings were only updated in 2008 and 2017. This accounts for the large difference in NZEB buildings between residential and non-residential buildings.

Table 6: Number of non-residential buildings at NZEB standard.

The Building Regulations for new buildings other than dwellings (non-residential) were updated in 2005, 2008 and 2017. From 2008, the Non-domestic Energy Assessment Procedure (NEAP) for energy and CO₂ calculations is required. The first significant change, including mandatory RES, in Building Regulations for non-residential buildings since 2005 came in 2017 (12 years later) while there were 3 incremental changes of regulations for residential buildings (in 2008, 2011 and 2019) in the same period.    

According to Law 90/2013, a NZEB is a building characterised by a very high energy performance in which the very low energy demand is significantly covered by RES, produced within the building system boundaries.

In the national plan for NZEBs (PANZEB)⁸, priority is given to ambitious renovation rather than new constructions, which have a very low rate in Italy.

The Italian authorities started implementing NZEBs in 2019 for public buildings, which will be fully implemented by 2021 for all new buildings. Some Italian local authorities anticipated these deadlines.

From 2021, all new buildings or buildings subject to a 'first-level major renovation' must meet the technical and performance requirements imposed by Annex 1 of the Ministerial Decree 06/26/2015 for NZEBs.

The number of NZEBs in 2018 amounted to around 1,400 buildings, mostly new construction (90%) and for residential use (85%), and it is estimated that the construction of NZEBs is increasing in all Italian regions.

Measures addressing the transition to NZEB include:

• Progressive strengthening of the building regulations: plans for implementing NZEB as a standard stem from 31 December 2018;
• Specific national incentives (thermal account and tax deductions) for existing public buildings undergoing renovation to NZEB level (demolition and reconstruction alternative is included);
• In new public buildings, the obligation for the share of RES is 10% higher compared to the minimum share required for private ones (i.e., 60% of minimum ratio of RES in energy supply).

Law 107/2015⁹ promotes new public schools with stricter earthquake-proof reinforcement and innovative energy systems as an extra requirement, increasing the ad-hoc fund of 23.9 million € in 2016 and 126 million €/year from 2017 to 2021. With the following Decree 94/2015, the Ministry of Education, University and Research allocated 300 million € to the Italian regions for the construction of 30 new innovative schools.

Within a research financed by the Ministry of Economic Development, in order to monitor and improve national and regional policies, ENEA has established a National Observatory, 'Osservatorio nazionale NZEB', that investigates numbers, typology, technologies and driving factors of Italian NZEBs according to the legislation in force. For the first three years, before the requirements scheduled by Directive 2010/31/EU, the activity focused on looking for real NZEB study cases across the country. By establishing the national EPC register and having NZEB mandatory requirements enter into force, the activity since 2019 has focused on analysing NZEB building characteristics by way of extracting information directly from the national database; this activity results in better utilisation of the more detailed available data.

The definition of NZEB was transposed into Regulation No. 383 in 2013. A cost-optimal study in 2014 showed that the defined level of NZEB (30 kWh/m² for heating) was difficult to achieve for almost all building types and the NZEB level was far from being cost-optimal, as the cost-optimal levels (for heating) were between 80‑90 kWh/m². Based on this conclusion, the NZEB definition was revised in 2015. Currently, the NZEB definition (40 kWh/m² threshold for residential buildings and 45 kWh/m² threshold for non-residential buildings) is closer to the cost-optimal level. The amendments to Regulation No. 383 also included building class rescaling and a plan to reach the NZEB level for new buildings by 2021.

Currently, a building shall be classified as a NZEB if it meets all the following requirements:

• The building energy performance indicator corresponds to Class A by concurrently ensuring conformity of indoor climatic conditions with the requirements of the laws and regulations in the field of construction, hygiene and labour protection.

• The total primary energy consumption for heating, domestic hot water supply, mechanical ventilation, cooling and lighting accounts for no more than 95 kWh/m².year.

• High-efficiency systems are used in the building, which ensure:

  • recovery of no less than 75% of the ventilation heat loss during the heating season;

  • the, at least partial, use of RES (RES>0).

• There is no low efficiency fossil fuel heating equipment installed in the building⁸.

Building classes are presented in Table 2 and a plan to reach the NZEB level for new buildings is given in Table 3.

Table 2. Building energy classes in Latvia

Table 3. Timeplan for reaching the NZEB level for new buildings.

As of mid-2021, all new buildings have to be NZEB. The NZEB standard entered into force in 2017 for residential buildings. For non-residential buildings, it is scheduled for mid-2021.

An example of a very energy-efficient new public building is the one housing the Nature and Forestry Administration⁵, which obtained an excellent score in its sustainability certification. This building is equipped with a water/water heat pump, a rainwater utilisation system, a LED-lighting system, a photovoltaic installation and an energy management system. The calculated heating energy demand of the building is 26.4 kWh/m².year and the primary energy demand is 70.6 kWh/m².year.

In the field of communication and information, free basic advice with respect to the energy-efficient renovation and construction of energy-efficient buildings has been provided since 2010 by myenergy.

Steps towards implementing the NZEB were undertaken by an inter-ministerial working group, which followed the development of the definition for NZEB¹ (Figure 4). The working group developed an action plan for achieving NZEB. Barriers were identified, including those related to the skills within the construction industry at various levels in the workforce currently employed in the sector. Quantitative targets were set for the progression towards NZEB, while the qualitative progression of the newly built stock towards NZEB was monitored.

The second set of cost-optimal studies has been developed, taking into consideration the measures to be implemented and the most effective investments that enable reaching NZEB level at the lowest cost. With the conclusion of the cost-optimal studies, the energy performance for future definitions of NZEB is being discussed.

Figure 4. NZEB primary energy levels for dwellings in Malta showing energy performance levels according to building typology. 

The energy performance coefficient has been tightened on 1 January 2015, as an intermediate step to reach the NZEB level. The next step was to specify the demands on primary energy consumption and the share of renewable energy up to the NZEB level. In March 2015, a first proposal for these requirements for new buildings was shared with stakeholders and sent for adoption by the Parliament in July 2015.

In 2018, a study on the cost-optimality, in accordance with Article 5 of the EPBD, has been carried out. On the basis of this study, the proposed requirements have been adjusted according to Table 4. They have been adopted in the amendment to the Building Decree 2012, which was published on 24 December 2019, to become effective as of 1 January 2021.

The triple NZEB requirements are referred to in the Netherlands as the Trias Energetica and are graphically shown in Figure 2.

Figure 2. Trias Energetica.

Table 4. Requirements for NZEB (adopted December 2019, source: Staatsblad 24-12-2019)

The Dutch government supports a programme from intermediary organisations, such as “NEPROM” (organisation of project developers) and “Bouwend Nederland” (organisation of builders), aimed at preparing the market players for increased demands to reach the NZEB level for new buildings.

In 2016, these intermediary organisations started a new programme under the name “ZEN” (i.e., “very energy-efficient new buildings”) to prepare the market players for tightening of the NZEB requirements in 2020.

RVO maintains a database and a website presenting a range of NZEB (meeting the preliminary NZEB-requirements) that have been constructed up to now⁵. The number of newly constructed NZEB will gradually increase to 100% after the implementation of the legislation regarding these buildings as of 1 January 2021.

The 2012 agreement on climate issues in the Norwegian Parliament stated that the building requirements in 2020 will correspond to NZEB level. This was reiterated by the government in 2015, when the new requirements were presented. However, the concept of NZEB in a Norwegian context has not yet been defined. A national NZEB definition is underway as part of the implementation of Directive 2010/31/EU.

Up until now, the national support scheme for buildings has been more ambitious than the energy performance requirements, and regional programmes have worked well to increase the amount of very energy efficient buildings. The Norwegian support scheme for new buildings meeting the criteria of the 'Passive House' standards has therefore been replaced by a new programme for even more ambitious projects. Support is given in particular to innovative solutions to improve technical building systems and heating systems.

Figure 1 shows one of the first residential houses in Norway with energy performance at what was expected to be NZEB, which is a good example of what can be achieved.

Figure 1. Norway´s first NZEB, a single-family house, was completed in 2012 and has since been in operation. The table shows the specified calculated energy need.

After the first full calendar year in use, the actual energy used for the operation of the house (excluding outdoor pool and other consumption not related to the building operation) was about 6,500 kWh, and electricity produced from the solar panels was 7,126 kWh.

The national plan for increasing the number of buildings with low energy consumption was adopted on 22 June 2015. This plan is still valid. The plan pays particular attention to the definition of NZEB and their specific characteristics, includes important information and tips for investors, designers and contractors, and describes the main and intermediate objectives related to improving the energy efficiency of buildings, including a timetable for achieving them in accordance to Article 9 §3 of the EPBD. The characteristic actions, mainly of governmental measures taken to promote buildings with low energy consumption, include the design, construction and reconstruction of buildings in a way that ensures their energy efficiency and increases the share of energy from RES in new and existing buildings. In addition, this document discusses the changes in regulations affecting the energy efficiency of buildings, making note of financial mechanisms addressed to different beneficiary groups, e.g., housing communities, individuals, local authorities, businesses and others.

The national plan:

• led to changes in technical conditions that new buildings must meet;
• led to changes in the act of 28 October 2020, amending the act on supporting thermo-modernisation and renovation;
• contributed to the development of the 2017 National Energy Efficiency Action Plan for Poland;
• led to changes in the Regulation of the Minister of Energy of 27 September 2018 on quality requirements for solid fuels;
• led to changes in the Regulation of the Minister of Development of 11 September 2020 on the detailed scope and form of a construction design.

The national plan also sets out plans for promoting the use of RES in buildings and the need to improve the technical conditions of the existing building stock. It identifies aspects of a comprehensive approach to energy efficiency, and its main objective is to achieve the provisions of Article 9 §1 of the EPBD. Following the aims of the directive, the goals are set as follows:

• from 31 December 2018, all new buildings occupied by public authorities or owned by the government should be NZEB;
• by 31 December 2020, all new buildings should be NZEB.

Since 2014, the national action plan for the progression to NZEB is supported by the revised legislation. The adopted preliminary definition of NZEB establishes a relationship with cost-optimal evaluations. NZEBs are defined as buildings that cumulatively offer:

i) very low energy demand with building components compatible with the upper levels (most efficient) of the cost-optimal evaluations;

ii) implementation of RES that covers a very significant fraction of the remaining building energy demand; 

iii) RES to be produced on site (whenever possible) and/or adjacent to the building. When local production is insufficient, the remaining production must be supplied as nearby as possible.

The full definition of NZEB was only concluded in the end of 2018. According to its requirements, a NZEB building must comply with the following, when compared to a reference building: 

i) Residential buildings:

a) Heating energy needs ≤ 75% of the reference heating needs (includes heating, cooling, domestic hot water and ventilation)
b) RES contribution ≥ 50% of total primary energy needs
c) Energy label A or A+

ii) Non-residential buildings:

a) Primary energy needs of regulated energy use ≤ 75% of the reference primary energy needs of regulated energy use (includes heating, cooling, domestic hot water, ventilation and lighting)
b) Energy label A or A+

Since the NZEB definition is still very recent, it is not yet possible to present information on how many NZEBs are built in Portugal, although buildings considering NZEB principles have been designed long before the NZEB definition came into force. Built in 2006, the Solar Building XXI, presented in Figure 1, is an example of a low-energy building using passive systems for both heating and cooling (ground cooling) to achieve NZEB. The main façade has a PV system with heat recovery which assists the heating in winter. In summer, a ground cooling system (earth tubes) is used to cool the building, together with night cooling strategies. The integration of RES in the Solar Building XXI design was one of the main objectives of the project. The last monitoring analysis, performed in 2011, has shown a total amount of electric energy consumption of 36 MWh, versus an amount of electricity produced by the three PV systems of almost 38 MWh.

Figure 1. Solar Building XXI, a low-energy building using passive systems for both heating and cooling (ground cooling) to achieve NZEB, even before the legislation came into force.

The national action plan for NZEB reflects the requirements and the streamlining of legal documents in order to implement NZEB standards. Milestones are presented as intermediate objectives and targets focused on 2016 (ultra-low level of construction and 2021 level of NZEB construction). The definition of NZEB has been transposed into law and extended by highlighting the importance of the efficient thermal protection of buildings. A definition of NZEB was written into law, in force since 2013. The energy used in NZEB should be to a large extent covered by RES. Implementing heat recovery systems/units with an efficiency higher than 60% is required in ultra-low and NZEB construction level. The construction of new public NZEB has been required since 1 January 2019. The national action plan requires that the design documentation for new public buildings should be in line with NZEB requirements when asking for a building permit as of 31 December 2018. For all new buildings, the date required for design documentation to be in line with NZEB requirements is 31 December 2020.

The action plan presents the gradual tightening of requirements with the global indicator for primary energy as the performance value. Energy class A1 has been required since 1 January 2016, whereas NZEB should achieve energy class A0 (when exporting or storing energy the classification can be A0⁺) for the global indicator as a performance value, required starting 1 January 2021.

At present, there are only a few examples of completed NZEB in the country. Some buildings are in the design stage, reflecting the requirements for building envelope components, the global indicator for primary energy and implementing RES, heat recovery systems and smart metering systems. Some buildings were already classified as A0⁺.

The Slovenian national plan for NZEB¹⁰ (2015) introduced the technical definition of NZEB based on the cost-optimal study (2014) for reference buildings. A core performance indicator of NZEB is primary energy, which is complemented by the requirement of a 50% share of RES in the final energy use (Table 1).

Table 1: Minimum requirements for new NZEB buildings

RES may be selected in consideration of their availability and acceptable NZEB technologies. In the future, the use of RES will be increased due to the growing share of RES in district heating systems which are subject to compliance with the energy efficiency targets already set in the Energy Act. Green transformation of district heating and cooling systems is also considered in the Integrated National Energy and Climate Plan of the Republic of Slovenia (2020). The nearly zero or very low amount of energy required in buildings is achieved by the limitation of energy needs for heating to a maximum value between 25 kWh/m².K and 15 kWh/m².K (EPC class A1, A2 or B1), depending on the shape factor (envelope area to building volume ratio) and the local climate.

A number of policies support the early construction of NZEB, including the following: the integration of NZEB criteria in revised building codes, the integration of energy efficiency in spatial planning, financial instruments for supporting private and public investments in new NZEB, demonstration projects, incentives for heating from RES (on-site, nearby and/or in district heating systems), the integration of NZEB criteria in green public procurement, energy information and advice, establishing a one-stop-shop portal, and the upskilling of blue collar workers and engineers for NZEB.

The national plan for NZEB also defined the intermediate targets for future NZEB, expressed in the floor area of new NZEB, and diversified by particular building types: single-family houses, multi-family houses, public buildings and other non-residential buildings. Comprehensive monitoring of newly constructed NZEB is not yet in place; the partial data are available only for NZEB supported by Eco Fund subsidies (Table 2).

Single-family houses are the prevailing type of early NZEB in Slovenia; after a decade of experience with constructing passive houses, low energy single-family houses and NZEB, there are several experienced designers, contractors and installers available within the market for single-family houses. Although the stakeholders involved in the building construction of multi-family houses turned out to be less experienced in NZEB, there are some successfully built private and public NZEB multi-family houses. In 2016, the Housing Fund of the Republic of Slovenia completed a NZEB multi-family house with 52 apartments and 4 individual staircases. This demonstration building has an average U-value of 0.26 W/m²K, EPC class A2, a primary energy of 36 kWh/m²year and a 72% share of RES (Figure 1).

Figure 1: NZEB multi-family house F3 Brdo, Ljubljana, built in 2016 as a demonstration project by the Housing Fund of the Republic of Slovenia (SSRS). The F3 Brdo building, with 52 apartments and a useful floor area of 5,708 m², holds an EPC class of A2 with a standard annual heat demand of 14 kWh/m².year, a total delivered energy of 49 kWh/m².year and a primary energy of 36 kWh/m².year. The share of RES in delivered energy is 72% (biomass: 48%, electricity: 28%, electricity from PV: 19% and heat from the environment for heat pumps: 5%) (www.brdo.ssrs.si) (Source: SSRS).

Figure 2. Airtightness quality control – Blower door tests for apartments and for the entire building were done in several stages during the construction of the building F3 Brdo, Ljubljana – a NZEB demonstration project of the Housing Fund of the Republic of Slovenia (2016) (Source: GI ZRMK, Photo: Andraž Rakušček).

Table 2: Intermediate targets for new early NZEB as given in the Slovenian national plan for NZEB (2015) versus actually constructed NZEB by September 2017.

The roadmap established in Spain for the construction and promotion of NZEB implies the compliance with the current CTE. These requirements have been demonstrated through the corresponding analysis of cost-optimal calculations, which indicates the most suitable and more restrictive possibilities according to what is considered state-of-the-art as well as the cost of implementing different construction solutions.

The roadmap establishes and provides for a revision of the limit values contained in the CTE in 2018, prior to the first phase of the NZEB entering into force according to the EPBD. Regarding the scope of planning and promoting the construction of NZEB, the Spanish administration has published two additional documents including regulatory developments: the Housing Plan of the Ministry of Development, and the Renovation Strategy of the Spanish Building Stock, following the requirement established in the Energy Efficiency Directive.

Both documents are published in the following links:

https://www.mitma.gob.es/portal-del-suelo-y-politicas-urbanas/sistema-de-informacion-urbana/enlaces-relacionados/plan-estatal-de-vivienda-y-rehabilitacion/presentacion

https://www.mitma.gob.es/el-ministerio/planes-estrategicos/estrategia-a-largo-plazo-para-la-rehabilitacion-energetica-en-el-sector-de-la-edificacion-en-espana

The Housing Plan analyses the Spanish building stock and establishes guidelines to promote the evolution towards a more efficient sector. It contributes to reactivating the real estate sector, which is fundamental for the promotion of the rehabilitation of buildings, and to regenerating urban or rural areas.

In parallel, the Renovation Strategy analyses the existing building stock, as well as the needs of the stock in the field of renovation, including renovation scenarios in order to meet the established requirements for both national and international commitments.

The NZEB definition has been fully implemented in Sweden as of 2017. The first NZEB-related requirement levels were set in 2015. The progression plan at the time indicated a planned tightening of the levels in 2020, when both primary energy number requirements would be tightened, and the primary energy factors would change.

The last step in the Swedish implementation of NZEB for new buildings was taken in September 2020 when the PBF and the BBR were revised and weighting factors, instead of primary energy factors, were introduced. The revision was implemented with the aim of creating a better balance between the different types of energy systems (electrical heat pumps, district heating, local boilers). The revision meant a tightening of the energy performance requirements for certain types of buildings and a relaxation of requirements for other types of buildings. The new requirements, however, include criteria that focus on building components: the average thermal transmittance (U_m) of the building envelope (A_om).

The amended regulation means that weighting factors replace primary energy factors when a building's energy performance (the primary energy number) is calculated. At the same time, a clarification that the small amount of energy supplied to NZEB should largely come from renewable sources was introduced in the PBF.

The next calculation of cost-optimal levels in accordance with the EPBD is expected to be called upon by the EC in 2023.

The 2012 UK national plan “Increasing the number of Nearly Zero‐Energy Buildings”¹⁶ covers all four UK jurisdictions. The plan was submitted to the European Commission and confirms the UK’s legally binding commitment (under the Climate Change Act 2008) to reduce greenhouse gas emissions by at least 34% by 2020 and 80% by 2050. In 2019, legislation increased the 80% target to 100% by 2050¹⁷. To meet these targets, the emissions footprint of buildings will need to be almost zero, which will mainly be achieved through:

• reducing the energy demand in buildings;
• decarbonising the heating and cooling supply.

England has made successive improvements in new‐build energy standards through changes to the Building Regulations (Figures 1 and 2).

The Government introduced Regulation 25B into the Building Regulations in 2012 to transpose the EU Energy Performance of Buildings Directive requirements for new buildings to be nearly zero energy buildings. Subsequently guidance has been provided for new buildings occupied by public authorities, which were required to be nearly zero energy buildings (NZEB) from 1 January 2019¹⁸.

NZEB statistics are not maintained in England. Figure 3 shows historical EPC records for energy efficiency ratings A and A+. The graph shows a steady increase in A rated non-residential buildings¹⁹ and a sharp drop in 2016 of A rated residential buildings²⁰, which levelled out between 2016 and 2018. Since 2018 there has been an increase in the number of A rated residential buildings. New building construction rates also affect these data.

Figure 3: Historical EPC ratings A and A+, England.

The current Building Regulations incorporate NZEB. Regulation 25B² states: “Where a building is erected, it must be a nearly zero-energy building.” and implementation dates align with the EPBD.

A review of Building Regulations Part L is ongoing. The review is intended to deliver, as a minimum, improvements to energy requirements where necessary to deliver NZEB standards at a cost optimal level or better to all new buildings in late 2021/ early 2022.

National application of the NZEB definition

NZEB statistics are not maintained in Wales. Figure 4 shows historical records of EPCs for energy efficiency ratings A and A+^7,8. The graph shows an upward trend in A rated buildings for non-residential sectors, and a sharp drop in 2015/16 of A rated residential buildings, which levelled out in 2017. Since 2018 there has been a sharp increase in the number of A rated residential buildings. New building construction rates will also affect these data.

Figure 4. Historical EPC A/A+ records for residential and non-residential buildings in Wales.

The UK national plan titled “Increasing the number of Nearly Zero‐Energy Buildings”¹³ covers all four UK jurisdictions: England, Wales, Northern Ireland and Scotland. See England report for details.

The Department introduced Regulation 43B into the Building Regulations in 2014³ to transpose the requirement of the Energy Performance of Buildings Directive requirements for new buildings to be nearly zero energy buildings. Subsequently an information note has been provided for new buildings occupied and owned by public authorities, which were required to be nearly zero energy buildings from 1 January 2019.⁵

NZEB statistics are not maintained in Northern Ireland. The following records of EPC A/A+ rated buildings provide an alternative for high performance buildings. These records have been sourced from the Northern Ireland EPC register, and are not publicly available. 

Figure 5. Historical EPCs classes A and A+, Northern Ireland. 2008-2019.

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The UK national plan titled “Increasing the number of Nearly Zero‐Energy Buildings”¹² covers all four UK jurisdictions: England, Wales, Northern Ireland and Scotland. See England report for details. Scotland specific details are included below.

Key elements and milestones, including national application of the definition of NZEB for new buildings

Building Regulations were amended in 2016 to transpose dates for nearly zero energy new buildings set out under Article 9(1). A review of the energy standards commenced in 2018. The publication of improved standards is programmed for 2020/21.

The Climate Change (Scotland) Act 2009¹³ creates a legal framework to deliver greenhouse gas emissions reductions. This Act was amended by the Climate Change (Emissions Reduction Targets) (Scotland) Act 2019¹⁴ which introduced revised interim targets and a target for net zero emissions by 2045.

In February 2018, Scotland published its Climate Change Plan: Third Report on Proposals and Policies 2018-2032 (RPP3)¹⁵. The RPP3 sets out the path to a low carbon economy while helping to deliver sustainable economic growth and secure the wider benefits for a greener, fairer and healthier Scotland in 2032. Chapter 2 of the RPP3 reports on progress to date and sets out actions to reduce emissions associated with Scotland’s building stock. Following the 2019 amendment of Scotland’s Climate Change Act¹⁴, an updated Climate Change Plan will be published later in 2020. 

Examples of existing NZEBs

NZEB statistics are not maintained in Scotland. The following records of EPC A/A+ rated buildings provide an approximate alternative for high performance buildings.

Figure 4 shows historical EPC records for ratings A and A+. The graph shows a sharp increase for domestic and non-domestic buildings from 2012 to 2015, a drop in 2016 in both sectors, and the domestic sector sharply picking up again in 2017. Note that new building construction rates also affect these data, and non-domestic EPCs were only registered from 2013¹⁶.

Figure 4. Historical EPCs Ratings A and Carbon Neutral/ A+, Scotland.

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