2.I.i. Progress and current status of new buildings (regulation overall performance) – OVERVIEW

Requirements in the OIB Guideline 6 for residential buildings differ to those for non-residential (public or commercial) buildings only in including requirements for the maximum energy demand for cooling. The remaining parameters regarding U-values, space-heating demand, the energy efficiency factor, heating and final energy demand are the same for residential and non-residential buildings.

Minimal U‐values requirements of the different building elements in the new OIB Guideline 6 (2019) are mostly the same as in the former version (2015). The maximum space heating demand requirement is tightened and requirements for heating energy demand are no longer included. The implementation date of the OIB Guideline 6 (2019) in the building regulations differs in the nine Austrian provinces. Therefore, there are two different effective dates mentioned according to minimum requirements: one valid from entry into force in the Austrian Province until the end of 2020 and one valid starting from 2021 (which is more tightened).

Residential buildings

The minimum requirements for residential buildings are now either:

• a combination of space heating demand, the final energy demand and indirectly the heating energy demand;

Table 1. Maximum requirements for the energy performance of new residential buildings by heating energy demand.

or, alternatively,

• a combination of space heating demand and final energy efficiency factor (f_GEE).

Table 2. Maximum requirements for the energy performance of new residential buildings by total energy efficiency factor.

Non-residential buildings

The minimum requirements for non-residential buildings are either:

• a combination of space heating demand, cooling energy demand, and final energy demand;

Table 3. Maximum requirements for the energy performance of new non-residential buildings by heating energy demand.

or, alternatively,

• a combination of space heating and cooling demand and final energy efficiency factor.

Table 4. Maximum requirements for the energy performance of new non-residential buildings by total energy efficiency factor.

Furthermore, the OIB Guideline 6 (2019) sets new additional requirements concerning the use of RES in buildings and includes measures for the protection of the internal building elements (e.g., walls) against harmful condensation resulting from thermal bridges, as well as improved protection against summer overheating for both residential and non-residential buildings.

The energy performance requirements have been mandatory since July 2008 for new buildings and for renovations in which a building permit is requested. The applicable energy performance requirements are set for primary energy consumption, insulation level, ventilation rate, overheating, technical installation, etc. These requirements are different for new or renovated buildings and units depending on the function (residential, office, educational, other non-residential). The requirements have been strengthened over the years, and in 2011, the energy performance requirement (E-level²) was tightened to become E70 (for housing) and E75 (for offices and schools). Moreover, a requirement regarding thermal bridges was introduced. The reduction in energy consumption linked to this reinforcement of requirements has been estimated by simulation to be 25%.

In 2014, although the global insulation requirement for the envelope (K-level³) K40 (for housing) and K45 (for offices and schools) did not change, some maximum U-values were tightened for all new or retrofitted elements of the building envelope.

In 2015, the E-level and K-level requirements for housing, offices and schools were replaced by two new requirements, referred to as ‘very high performance’ requirements, one concerning the total primary energy consumption (PEC), and the other concerning the net heating requirement (NHR). The requirements by type of unit are presented in Table 1.

Table 1. Requirements applicable from 2015 to 2017 for new units by unit type*.

Units considered as new⁷ (>75% change in the envelope and replacement of all technical installations) are subject to the same requirements as new units, with the exception of the net energy use for heating and the total primary energy consumption, for which the requirement is lowered by 20%. 

Since 1 July 2017, the requirement for the total energy consumption (PEC) is extended to all non-residential buildings and units (offices, schools, shops, healthcare facilities, courts, laboratories) and the net heating requirement (NHR) for non-residential units was abandoned.

In 2019, the total primary energy consumption (PEC) for non-residential units was reinforced, and a new reinforcement is planned in 2021 in order to achieve NZEB requirements for all unit types. Those requirements will be further strengthened in 2022. The reinforcements are applied to all functional units of public and private buildings.

The requirements as planned for 2021 are presented in Table 2 by unit type.

Table 2. As of 1 July 2017, requirements for new units by unit type*.

The most important requirement for new buildings concerns the dimensionless E-level¹. The E100-level was introduced in 2006 for new houses, offices and schools. Up to 2019, it was subsequently reduced by 60% to E40, based on cost-optimal studies. Following the cost optimal study of 2012, the path to E30 for NZEB houses was set out in 2013 and confirmed by new cost-optimal calculations in 2015 and 2017.

In 2017, the E-level, including an NZEB-path towards 2021, was introduced for all non-residential buildings (hotels, hospitals, retail, etc.). A new cost-optimal study was carried out in 2018.

Since 2006, existing requirements have been strengthened for all new buildings. A number of new requirements were introduced in the following years (in 2012 for net energy demand, in 2014 for the minimal share of RES, in 2018 a replacement for the K-level, i.e. the S-level²). This set of requirements and its cost-optimal levels were evaluated in 2018, mainly based on cost-optimal studies³.

Until 2019, more than 395,000 final declarations (calculations of the energy performance requirements in as-built situations) were collected in the central register (Figure 2).

Figure 2. Total number of final energy performance declarations (cumulative).

The analysis by the Flemish Energy Agency⁴ indicates that the average E-level decreases every year (Figure 3). This evolution is most evident for new single-family houses. The number of NZEB single-family houses with an E-level lower than E30 rises from only 4% for building permits in 2010 to more than 30% for building permits in 2014 and more than 60% for building permits in 2017 (Figure 4).

Figure 3. Evolution of the average energy performance level of new residential buildings, per year of the building permit application.

Figure 4. Share of NZEB single-family houses per year (application of building permit).

The administrative procedure for new buildings, subject to an overall energy performance level requirement, is as follows:

The amendments to the regulation also set requirements for accrediting qualified experts, which include the requirement to undergo training and pass an examination. To ensure a smooth transition, all previously accredited experts³ could directly attempt the examination without going through training up until the end of 2016.

Meanwhile, the administration put the necessary elements in place to prepare the sector for the arrival of the 2021 building regulation, which includes the NZEB requirements. Continuous training for qualified experts has been taking place since April 2017.

The Energy Efficiency Act, the Law on Spatial Planning and the relevant regulations that follow set out the legislative and technical measures that should, by law, be applied to new buildings. The energy performance of a new building, before the commissioning stage, shall be certified by an “Energy Performance Certificate of New Building”. This is valid for six years from the date of commissioning of the building and is issued on the basis of the energy performance of the building according to the development and project design of the building. Minimum energy performance requirements have been gradually tightened since the EPBD was first implemented. At present, these requirements are set with the goal of achieving cost-optimal levels and have been defined for ten categories of buildings, depending on their assigned use. A new building meets the requirement for energy efficiency when the value of their integrated energy efficiency indicator (specific annual expenditure of primary energy in kWh/m²) corresponds to at least the energy efficiency class “B”.

The National Plan for Nearly Zero-Energy Buildings (NZEB), adopted in December 2015, provides the national definition and the technical parameters of NZEB and the national annual targets for construction of new NZEB by 2020.

Based on cost‐optimal analyses that were carried out in 2013 and 2014, requirements are set on individual types of buildings regarding annual energy needs for heating per usable floor area of a building (Q"_H,nd). The requirement regarding annual primary energy per usable floor area of a building (E"_prim) is included in the Technical Regulation on the rational use of energy and thermal protection in buildings (OG 97/2014 and 130/2014) – prior Technical Regulation on energy savings and thermal protection in buildings ceased to be valid. The remaining requirements for annual delivered energy per usable floor area of a building (E"_del) are specified in the new Technical Regulation on the rational use of energy and thermal protection in buildings, published in November 2015 (OG 128/15).

The new Technical Regulation on amendments to the Technical Regulations on the rational use of energy and thermal protection in buildings (OG 128/2015, 70/2018) entered into force on 9 August 2018.

The new amendments to the technical regulation introduce several changes and new definitions related to:

• the surface of the useful area of the heated part of the building, A_K (m²);
• delivered energy;
• NZEB;
• the maximum allowed values of the heat transfer coefficient U [W/(m²K)];
• requirements for the building parts to be fulfilled when designing new buildings and designing the reconstruction of existing buildings;
• established default values for the calculation of the technical characteristics of certain construction products required by this regulation;
• the prescribed maximum permissible values of the annual heat energy required for heating per unit of useful area of the heated part of the building, Q’’_H,nd [kWh/(m² year)];
• the maximum permissible values of the annual primary energy per unit of useful area of the heated part of the building E_prim [kWh/(m² year)];
• for new buildings heated and/or cooled at a temperature of 18°C or more, for existing buildings with reconstruction being performed in a way prescribed by Article 45, Paragraph 7 of technical regulation and NZEB.

The technical requirement for the rational use of energy and thermal protection of the building is further determined by the maximum allowed annual heating energy requirement per unit of useful area of the heated part of the building Q’’_H,nd [kWh/(m²·year)] and the maximum allowed annual primary energy per unit of useful surface area of the heated part of the building E_prim[kWh/(m²·year)] based on cost-optimal levels.

A new residential building (multi-residential building or family house) and a non-residential NZEB, depending on the type, must be designed and constructed in such a way that the annual heat energy required per unit of useful area of the heated part of the building, Q’’_H,nd [kWh/(m² year)] is not greater than the allowed values set out in Table 8 of Annex B to the new amendments on the Technical Regulation.

The annual primary energy per unit of useful surface area of the heated part of the building E_prim [kWh/(m² year)] includes the energy listed in Table 8a and should not be higher than the values set out in Table 8 of Annex B to the new amendments on the technical regulation for new buildings.

The main design of buildings other than buildings owned and used by public authorities, which are subject to issuing a building permit, shall be made in accordance with the provisions for NZEB if the request for the building permit has been submitted after 31 December 2019.

The main design of buildings owned and used by public authorities, which are subject to issuing a building permit, shall be made in accordance with the provisions for NZEB if the request for the building permit has been submitted after 31 December 2017¹.

Depending on the building type, the requirements are prescribed for the maximum E"_prim, E"_del, Q"_H,nd, the annual energy need for cooling per usable floor area of a building (Q"_C,nd), the maximum permitted thermal transmittance for individual building components of the building envelope (U-value), the reduction of the effects of thermal bridges (for this purpose, a catalogue of good solutions² as integral part of the Technical Regulation on rational energy use and thermal protection in buildings has been developed), the efficiency of technical building systems, the efficiency class of the building automation and control systems, the airtightness, and the share of RES (See the Key Indicators and Decisions, KIDs). Provisions for indoor environmental quality (including air quality, thermal comfort, lighting and acoustics) are also provided.

The results of the first calculation for setting the minimum energy performance requirements at cost-optimal levels have indicated that, while energy class B was at the optimal level, requirements regarding insulation and RES were much less ambitious than the optimal levels. At the same time, the economic benefit of shading for all buildings and improving lighting in office buildings has been made apparent by the results of the calculation.

In order to set minimum requirements at cost-optimal levels by 2017, the maximum U-values were reduced by approximately 15% in December 2013, and a maximum shading factor for windows was introduced⁴. This factor is the product of the solar radiation reduction factor of fixed shading, external removable shading, and transmission of solar radiation through glazing. Also, according to the requirements for non-residential buildings, at least 3% of the total energy consumption should come from RES.

From 1 January 2017, the U-values of the building envelope were reduced even further, closely approaching the requirements for NZEB. Additionally, the minimum proportion of total energy consumption that should come from RES, both for residential and non-residential buildings, has significantly increased.

The new minimum energy efficiency requirements will take effect in 2020. These will require all new buildings to be energy class A and cover at least 25% of their primary energy consumption from RES except for hotels, for which the requirement is 9%. Maximum primary energy consumption is set, while additionally for residential buildings a maximum heating demand must be obtained. The new requirements are the result of the second calculation of the cost-optimal levels carried out in 2018, as well as the public consultation with all stakeholders.

In order for a new building to be constructed, the builder must document that it meets the minimum values for primary energy per year, total delivered energy per year and the average U-value, as well as minimum NZEB requirements. The primary energy indicator must reach EPC level C (in exceptional cases level D), which is set as the minimum requirement for the building to be constructed. This applies to all types of buildings (residential, non-residential, public, etc.). Decree 264/2020 also sets minimum energy performance requirements/values for technical building systems and requirements for nearly energy zero buildings. Figure 1 shows the evolution of the energy performance/class for new family houses constructed in the Czech Republic between 2010 and 2017. Although the NZEB level for family houses entered into force in 2020 (NZEB level for new buildings with total floor energy area less than 250 m² in the year 2020), the majority of buildings fulfilled stricter criteria years before (since 2016).

Figure 1: Evolution of the energy performance/class for new family houses constructed in the Czech Republic between 2010 and 2017.

The current energy performance requirement methodologies for new residential and non-residential buildings were implemented through the Danish Building Regulation 2006 as an implementation of Directive 2002/91/EC.

Denmark has focused on reducing energy consumption in new buildings for many years. The energy consumption in new buildings has steadily declined since introducing the first energy requirements in building regulations in 1961. Since 2006, requirements have been set for a building's overall energy consumption in accordance with the EPBD. In 2008, the Danish government entered an energy agreement on reducing the energy needs of buildings by 25% in 2010, 25% in 2015 and another 25% in 2020 – a total reduction of 75% compared to the 2006 requirements, which was supported by a broad majority of political parties in the Danish Parliament. In 2010, the first steps were taken by introducing Building Regulation 2010 (BR2010), in which the energy requirements were tightened by about 25% and a voluntary energy class was revised and renamed 'Low-energy Class 2015 (Lavenergiklasse 2015)'. Already in 2011, the new 'Building Class 2020' was introduced – also as a voluntary building class – due to requests from the Danish building industry to have sufficient time for developing new products for the future.

In July 2016, the previously voluntary 'Low-energy Class 2015' became final and binding and was renamed the 'Danish Building Regulation 2015 (BR2015)'. The BR2015 sets minimum energy performance requirements for all types of new buildings. In addition to the minimum requirements, the BR2015 also sets requirements for a voluntary low-energy class, 'Building Class 2020' (equivalent to NZEB level at that time). In 2018, the energy performance requirements were slightly changed, primarily due to upgrades of the primary energy factors and the calculation procedure, and were implemented in the Building Regulation 2018 (BR2018). The voluntary class of 2020 was evaluated to be beyond the cost-optimal level and will remain a voluntary low energy class with a small change in the requirements due to updated primary energy factors.

Figure 1. Danish Building Regulations 2018. The Danish Building Regulation (current and historic) can be found at: http://bygningsreglementet.dk.

The minimum energy performance requirements are expressed as a primary energy performance indicator (EPI). The maximum primary energy values are listed in Table 2. Buildings that will be erected after 31 December 2019 and waiting for a construction permit must meet the NZEB (class A) requirements. Small residential buildings (detached houses, row houses) with a heated floor area <220 m² are exempted from this requirement and must meet low-energy building (class B) requirements without considering local renewable energy production. Estonia has not set minimum requirements for U-values.

The building has to meet the minimum energy performance requirements as a whole. For detached and terraced houses, compliance with the minimum energy performance requirements can also be demonstrated by a simplified calculation. From 2008 to 2018, this alternative method was based on the specific heat loss tabulated values through the building envelope. This method required only envelope heat transfer coefficients (U-values) to be subjected to heat loss calculations for conduction and infiltration losses and could be used if a mechanical supply and exhaust ventilation system with specified heat recovery and specific fan power were used. Depending on the heat source, specific heat loss values are set, so that they comply with minimum energy performance requirements. With this method, no further energy calculation was required. For example, the maximum specific heat loss value to be fulfilled in the case of a ground source heat pump serving as the heat source was 1.0 W/(m².K), and in the case of a gas boiler, it was 0.6 W/(m².K). It is important to note that these values are not U-values, but specific conduction (average U-value of building envelope including thermal bridges) and infiltration heat loss values calculated per heated floor area.

From 2019, this alternative method was further developed and implemented as an Excel calculator. Heating energy need is still calculated from the specific heat loss but corrected with solar heat gains. Building envelope and technical systems (ventilation, heating, solar collector and photovoltaic) input data can be specified by the user, and the calculator also uses certain simple rules, e.g. window to wall ratio multiplied by the solar heat gain coefficient, for overheating risk estimation.

* EE EPI values in other columns include appliances in non-residential buildings, and lighting and appliances in residential buildings that are not included in EPBD energy uses. As being tabulated fixed values, EPI values for EPBD scope can be reported.

Table 2. Primary energy requirements for buildings (bold values denote minimum requirements for new built structures).

Requirements are also set for summer thermal comfort in buildings. For residential buildings, this requirement is defined as the hourly mean indoor temperature in excess of the maximum limit of 150 degree-hours (ºCh) over +27°C during the summertime period (from 1 June to 31 August). For non-residential buildings, this requirement is defined as the hourly mean indoor temperature in excess of the maximum limit of 100 degree-hours (ºCh) over +25°C (+27°C for warehouses, industrial buildings) during the summertime period (from 1 June to 31 August, educational buildings 1 May to 15 June and 15 August to 30 September). For compliance assessment, detailed procedures are described in the regulation 'Calculation Methodology for Building Energy Performance Calculations'⁹. Temperature calculations are needed for typical living rooms and bedrooms that are most likely to encounter overheating. Temperature calculations for non-residential buildings are needed for typical room types. The verification is to be conducted considering rooms as single zones, and by using dynamic simulation software.

Finland’s National Building Code has set minimum requirements for the thermal insulation and ventilation of new buildings since 1976. These requirements have been amended and enhanced several times to improve the energy efficiency of buildings.

The requirements for the overall energy consumption of buildings are set with the new building code that came into force on 1 January 2018 for all new buildings. The aim of the regulations is to set the level for NZEB in Finland. The development of the requirements is shown in Table 1.

Table 1: Development of minimum requirements for new buildings (all building types).

The overall energy consumption is calculated using standard user profiles and primary energy factors (weighting factors) for different energy sources (Table 2). For single-family homes and apartment buildings an alternative method was introduced that is based on requirements for building components.

Table 2: Primary energy factors.

.

The current thermal regulation in response to the EPBD is the RT 2012 (Réglementation Thermique 2012)⁴. It has been mandatory only for some public buildings since the end of 2011, and for all new buildings since 2013. This regulation is the result of a two year-long dialogue with all stakeholders, including seven consultative conferences, where the work in progress was presented. The next thermal regulation, RE2020, is planned to be released in January 2021. It will contain even more ambitious objectives, since it will also include environmental requirements, based on a life-cycle analysis. Indeed, in France, different simulations have shown that about two thirds of a new building carbon impact occur during the construction phase and not during the use phase, meaning that reducing construction climate impact also requires to regulate construction itself.

In order to anticipate this new regulation, a testing scheme called ’E+C-’ (standing for Energy plus Carbon minus) was launched for volunteering contractors in late 2016.

As a first step towards NZEB, the requirements for new buildings were tightened in January 2016 (Table 2). The maximum primary energy demand now equals 75% of the 2014 value, whereas the requirements addressing the thermal envelope were strengthened by 20%. The German report¹⁰, as required by Article 5 paragraph 2 of the EPBD, proved the 2016 requirements to be cost-optimal.

Table 2. Requirements for new residential buildings: reference construction to determine the maximum primary energy demand and additional requirements to building envelope and system performance.

New buildings or building units must meet minimum energy performance requirements (class B) set out in the KENAK. In July 2017, with Ministerial Decision (M.D. DEPEA/oik. 178581, GoG B’ 2367/12.07.2017) the KENAK was amended according to the results of a cost-optimal study. This study determined the minimum energy performance requirements for new buildings or building units and for existing ones that undergo a major renovation, so that the maximum energy savings are achieved with a lower cost impact. The results of the cost-optimal study were also incorporated into the new technical guidelines of the Technical Chamber of Greece (TOTEE), which were approved in November 2017 with Ministerial Decree (M.D. DEPEA/oik. 182365, GoG B’ 4003/17.11.2017).

Moreover, in combination with the obligation set in Law 4122/2013, every new building of the public sector from 1 January 2019 should be NZEB. This obligation also applies for all new buildings constructed after 1 January 2021.

The definition of NZEB has been used since 2013. The national plan for increasing the number of nearly zero-energy buildings was issued in August 2018 and defined, among others, that a new building may be characterised as a nearly zero-energy building if it falls at least under energy class A, while an existing building when it falls at least under energy class B+; this was incorporated into Greek legislation through Ministerial Decision YPEN/DEPEA/85251/242 (GoG B’ 5447/5.12.2018). Nevertheless, a decision on the minimum share of RES and the way it contributes to primary energy consumption is still pending. The YPEN is expected to procure a study in the first semester of 2020 in order to deal with these issues.

At the stage of issuing a building permit for new buildings or building units, additional documentation must be prepared and submitted to the relevant Building Office Authority. This documentation accompanies the energy study and contains the technical, environmental and economic feasibility of the installation of at least one of the following alternative energy supply systems:

• decentralised energy supply systems based on RES;
• combined heat power (CHP);
• district heating or cooling systems in the region or block;
• heat pumps that meet the minimum eco-labelling requirements¹.

For new buildings or building units, it is obligatory since 2011 to cover part of the hot water needs from solar, thermal or other RES/CHP systems. The minimum percentage of the solar share on an annual basis is set at 60%. Non-application of the above rate requires adequate technical documentation in accordance with current legislation and the prevailing conditions. 

The first ministerial order (7/2006. (V. 24) Decree about Determination of Energy Efficiency of Buildings) to transpose Directive 2002/91/EC was issued in May 2006 and has been in force since 1 September 2006, with several modifications having taken place since. For buildings supported by public funds and for any construction projects financed by the state budget, cost-optimal requirements are applicable since the beginning of 2015. The same requirements were introduced for all new buildings (with exceptions allowed by the EPBD) and those undergoing major renovations as of 2018. The fulfilment of the cost-optimal level requirements is a precondition for any subsidy. Commissioning of such a building could be realised by the end of 2020.

An amendment entered into force on 29 November 2019 with the aim to assess the real energy characteristics of district heating. Thus, during the energy calculations, each district heating system is evaluated according to its own characteristics. Goal of this amendment was to improve the energy performance of the domestic building stock, while also promoting the energy and climate protection benefits of district heating in line with other energy strategy goals.

With effect from 1 January 2021, the Decree has again been amended, in order to replace the 25% renewable share on one hand and to promote electromobility on the other.

The amendment allows the builder, if justified, to replace the requirement for the share of renewable energy as defined in Directive 2010/31/EU by meeting an increased cost-effectiveness requirement. The amendment thus demonstrably retains the requirement to encourage the use of renewable energy, but also provides acceptable alternative requirements for buildings where the share of renewable energy cannot be reasonably (technically, economically, or environmentally) met.

Regarding the promotion of electromobility, as a result of the modification of the Decree, in accordance with the EU Directive, in the case of a new building or a major renovation or extension of an existing building where the extension exceeds 100% of the useful floor area of the building to be extended, the building must meet the new requirements for electromobility. This means that new non-residential buildings with more than ten parking spaces (e.g., office buildings) must be equipped with an electrical charging point at every five parking spaces. For new residential buildings, any tenth parking space must also be equipped with electrical cables. For other existing non-residential buildings with more than twenty parking spaces, an electric charging point is required from 1 January 2025.

NZEB requirements, defined by the 7/2006. (V. 24) Decree since 2016, were introduced in 2019 for public buildings and will be mandatory from 2021 for all new buildings. The NZEB threshold of the specific primary energy consumption for residential buildings is 100 kWh/m²year. For educational buildings the NZEB levels are 85kWh/m²year and for office buildings 90 kWh/m².

In addition, after entry into force, on 1 January 2022, of the amendment of Act LVII/2015 on energy efficiency, the previous Hungarian regulatory environment for the on-site inspection of heating and air-conditioning systems will also undergo a significant modification. An IT system supporting the performance and control of the energy review is currently being developed.

Also, in order to properly transpose Article 20 of the EPBD, the Hungarian Chamber of Engineers has been appointed to carry out tasks related to informing the retail and business sectors.

Overall maximum permissible energy performance and CO₂ emissions requirements were introduced for residential buildings in 2005, and for non-residential and public buildings in 2008.

The Energy Performance Coefficient and Carbon Performance Coefficient are defined as the ratios of calculated primary energy consumption and corresponding CO₂ emissions for the proposed building relative to a reference building.

The Maximum Permitted Energy Performance Coefficient and Maximum Permitted Carbon Performance Coefficient for new residential buildings are given in Table 1.

Table 1: Maximum Permitted Energy Performance Coefficient and Maximum Permitted Carbon Performance Coefficient for new residential buildings.

Energy from RES is mandatory for new residential buildings since 2008. In 2008 and 2011, the minimum requirement was 10 kWh/m².year thermal energy or 4 kWh/m².year electrical energy. In 2019, the RES requirement was changed from 10 kWh/m².year to a Renewable Energy Ratio (RER) of 0.2 or 20%. A RER of 0.2 represents 20% of the primary energy from RES technologies to total primary energy as defined and calculated in DEAP.

The Maximum Permitted Energy Performance Coefficient (MPEPC) and Maximum Permitted Carbon Performance Coefficient (MPCPC) for new non-residential buildings are given in Table 2.

Table 2: Maximum Permitted Energy Performance Coefficient and Maximum Permitted Carbon Performance Coefficient for new non-residential buildings.

For all new non-residential buildings, the 2017 NZEB Regulations require 60% reduction in the calculated energy use compared to the 2008 Regulations. This means an improved energy performance for the fabric, services and lighting specifications. The comparison reference and notional buildings were updated in 2017 thus the maximum coefficient values remain at 1.0. In 2017, a mandatory requirement for RES was introduced. RES must in general provide 20% of the primary energy use, however there is flexibility where the building is more energy efficient than the regulations. This typically corresponds to an A3 energy rating.

Waiting for the complete implementation of Directive 2018/844, Decree 26.06.2015 'Minimum Requirements' is in force and provides:

1) Minimum energy performance requirements for buildings, building systems and building components:

The minimum energy performance requirements for new buildings (and major renovations) are based on the application of the cost-optimal methodology results (EPBD, Article 5) and include heating, cooling, domestic hot water and ventilation for residential buildings as well as lighting and internal transports (lifts, escalators) for non-residential buildings.

The overall energy performance of new buildings varies with typology and climatic zone.

The minimum energy performance requirements were set for two different time steps:

- from July 2015

- from January 2019 (for public buildings) and from January 2021 (for all the other buildings)

2) Rules for taking into account the use of RES in buildings and the system boundary:

Compensation between energy needs and renewable energy produced on-site is allowed only for the same energy carrier on a monthly basis and only to cover the total energy demand for that carrier (the exported energy is not taken into account).

3) The energy performance calculation methodologies:

The calculation methodologies are based on national standard UNI/TS 11300 (series from 1 to 6)⁵, which constitutes the national instrument for applying the set of standards developed by CEN to support EPBD implementation. UNI/TS 11300 series are presently under revision to be in line with the new set of CEN standards defined under mandate M/480. The adoption of the hourly calculation instead of monthly calculation is under consideration.

4) Primary energy conversion factors:

Renewable, non-renewable and total primary energy conversion factors are defined for each energy carrier (see Table 1).

5) Definition and requirements for NZEB:

NZEB are new or renovated buildings respecting:

• all the requirements included in Decree 26.06.2015 'Minimum Requirements', with the limit values set for 2019/2021;
• the RES requirements included in Decree 3.3.2011 n. 28 (i.e., 50% of the energy used for heating, cooling, ventilation and domestic hot water).

Table 1. Primary energy factors.

Before 1980, building envelope characteristics were based on requirements for preventing moisture from forming on the inner surface of the outer walls, and for preventing freezing through the walls. For properly constructed buildings, the envelope heat transfer coefficient U-value was usually less than 1.3 W/(m² K). From 1980 onwards, buildings were built in accordance with a formal USSR Standard for the thermal resistance of the envelope, e.g., improving wall U-values to 1.1 W/(m² K). Significantly more demanding requirements were adopted by the Ministry of Architecture and Construction of the Republic of Latvia in September 1991. Since 2003, the LBN 002-15 (approved in 2001 and tightened in 2015 following cost-optimal studies) has been in force. Requirements for the minimum permissible level of energy consumption for heating (amendments in Regulation No. 383) were set in 2015.

A timetable to reinforce energy performance requirements for residential buildings and a first step to reinforce energy performance requirements for non-residential buildings have been defined in 2012 and 2014, respectively.

A new step on the path towards the non-residential NZEB entered into force in 2015, with the non-residential NZEB entering into force by mid-2021.

For residential buildings, a similar stepwise approach was used with reinforcements in 2012 and 2015. The last step of the reinforcement for new residential buildings entered into force in 2017 and thereby introduced the residential NZEB as a standard.

Figure 1. Reduction of energy needs over time for residential buildings. Source : Dr. Markus Lichtmess, Goblet Lavandier & Associés Ingénieurs-Conseils S.A.

In 2020, Luxembourg implemented the following important requirements for residential buildings:

• new buildings need to be equipped with ducting infrastructure for electromobility and photovoltaics;
• mandatory 'as built' EPC;
• the definition of the NZEB standard as the new standard from 1 January 2017 onwards;
• changes to the requirements and calculation methods for thermal protection in the summer, with the aim of limiting summertime overheating;
• the ability to take photovoltaic production into account, at least partly;
• a change in the calculation method for global requirements (primary energy needs and heating energy needs) towards implementing the reference building procedure;
• the adjustment of calculated energy needs in the EPC to more adequately reflect the real energy consumption;
• the introduction of an interface in the EPC calculating tool for measured airtightness values.

Figure 2. Integration of photovoltaic production. SOURCE: Dr. Markus Lichtmess, Goblet Lavandier & Associés Ingénieurs-Conseils S.A.

Figure 3. Methodology of the reference building. SOURCE: Dr. Markus Lichtmess, Goblet Lavandier & Associés Ingénieurs-Conseils S.A.

The minimum energy performance requirements in place, which came into force in 2016, were based on the cost-optimal studies carried out in 2013-2014. They set an overall energy performance level as guided by the cost-optimal studies. The requirements also introduced minimum levels of performance for technical building systems, together with requirements for controls of such systems. The first set of cost-optimal studies determined that the cost-optimal level varies considerably with both the building use and building typology. This is reflected in the overall energy performance for different building uses and building typologies.

The second set of cost-optimal studies was carried out on an array of reference buildings to reflect various building typologies with particular emphasis on buildings which are disproportionately highly representative in the local building stock and therefore contribute significantly to the use of energy. The reference buildings included sport complexes, restaurants, hotels, homes for the elderly, shops, existing offices, new offices, existing residences and proposed residences. A number of buildings were chosen for each of the building typologies such that the cost-optimal level could be assessed over a representative sample of the building stock.

The difference between the minimum requirements and the determined cost-optimal level varies according to building typology. The installation of renewable energy sources was found to be cost-optimal for all building typologies. The development of new minimum requirements that address the results from cost-optimal studies and advances in technology are under way. These are expected to deliver new possibilities in the design and construction of buildings to satisfy NZEB requirements.

Figure 3. Extract from studies for offices showing energy performance levels over a spectrum depending on size and configuration of buildings.

The Energy Performance Standards (EPN), established in 1995, were replaced in July 2012 by a new standard, the Energy Performance Standard for Buildings (NEN 7120, also referred to as EPG, that replaced both the existing residential and non-residential standards.

The main requirement for the energy performance of new buildings is the energy performance coefficient (in Dutch the ‘energieprestatiecoefficient”), setting minimum energy performance (MEP) for new buildings. This indicator is based on the calculated total primary energy consumption of a building based on a series of indicators, e.g., heating, ventilation and lighting, adjusted to the useful floor area and the renewable energy produced by the building. This indicates the building energy performance in MJ/m².

The calculation of the energy performance coefficient is mandatory for all new buildings and for large renovations.

The energy performance coefficient calculation is part of the building permit application.

As of 1 January 2021, NZEB-requirements will become effective for all new residential and non-residential buildings.

Energy Performance Calculation Method in the Netherlands

The energy calculation method for new and existing buildings is defined in Standard NEN 7120 that is in line with the CEN standards³. This calculation of the primary energy consumption of a building is based on monthly climate data that is adjusted for physical processes with a shorter timeframe, e.g., solar gains and heat accumulation. The calculation of the thermal quality of the building envelope includes thermal bridges, ventilation and air infiltration, hot water use, efficiency of heat and cold generators, renewable energy used both in and near the building, and the contribution of passive energy, lighting and daylighting. Shading caused by the building itself is included in these calculations. Shading by other buildings is not taken into account.

As of 1 January 2021, the energy performance requirements for new buildings will be calculated with the newly developed energy performance calculation method NTA 8800⁴ (Nederlandse Technische Afspraak), which will be applicable for all buildings, both residential and non-residential. This method will also be used to calculate and determine the energy performance certificate for all existing buildings, both residential and non-residential. NTA8800 is based on the CEN Standards.

The quotient of a building’s calculated annual primary energy needs to the allowed primary energy performance provides the energy performance coefficient (Table 1).

In 2012, a broad agreement in the Norwegian Parliament stated that all new buildings should be at 'Passive House' level in 2015, and at NZEB level by 2020.

The two Norwegian standards for passive houses and low-energy buildings are already in place: the NS 3700 for residential buildings and the NS 3701 for non-residential buildings². The definition of 'Passive House' level from the political agreement was to be implemented in building regulations in 2015. In November 2015, the new requirements were published and have been effective since January 2017. The requirements of 2015 do not fully meet the Norwegian passive house standards but are set at a more cost-optimal level.

The requirements for 2020 and the national definition of NZEB are in preparation so as to comply with Directive 2010/31/EU.

The energy performance requirements entered into force on 1 January 2014 and determined obligatory minimum requirements as follows:

• from 1 January 2017 for new buildings³;
• from 1 January 2019 in the case of buildings occupied and owned by public authorities;
• from 1 January 2021 for all buildings (dates refer to building permit).

A detailed description of the regulation is given in the CA EPBD Book 2016 country report of Poland.

The Portuguese legislation focuses heavily on new buildings, both residential and non-residential, with the primary objective of setting the pace for more efficient buildings to come. This objective considers the substantial share of energy consumption spread across buildings throughout Europe, with Portugal being no exception. To achieve this goal, a stepped tightening of requirements of the 2013 regulations has been implemented, focusing on the building envelope and the building’s technical systems. The first level of tightened requirements was defined to be applicable until the end of 2015, after which a stricter level of requirements came to force in the beginning of 2019, preparing the path towards NZEB.

This significantly strengthened regulation² brings new challenges to building design in order to fulfil a robust level of minimum requirements and an important contribution from RES.

Requirements for the energy performance of new buildings have been set since 2016. According to these, new buildings, including new public buildings, should fulfil the requirements set for ultra-low energy constructions and achieve the global indicator for energy class A1 (until the end of 2015, the requirement for low-energy buildings was energy class B). For all building categories and construction levels, a minimum air change rate of 0.5/h is required. Heat recovery systems with a minimal efficiency of 60% for the ventilation of spaces is further required. Starting 1 January 2021 new buildings should fulfil the requirements set for NZEB and achieve the global indicator for energy class A0. If the NZEB exports or stores energy, it is classified in subclass A0⁺. The requirements for the global indicator for primary energy are set depending on the category of the building. New public buildings must fulfil NZEB requirements as of 1 January 2019. The requirements for building components are the same for residential and non-residential buildings.

In line with the EPBD and according to the long-term planning integrated into the building codes PURES 2010, as of January 2015 more severe minimum requirements for maximum energy needs for heating have entered into force⁶. This change had already been integrated into the transitional provisions of PURES 2010 and is compliant with the cost-optimal study outcome. Minimum requirements are expressed using performance-based and energy-related requirements as well as detailed technical requirements for building components and systems.

In 2015/2016, the building codes were put under revision in order to take into account the outcome of the cost-optimal study (2013, 2018), and mainly to include further details associated with the national definition of NZEB, as well as to make the necessary changes in the calculation methodology pursuant to the new CEN EPBD standards. The revision process is still ongoing and shall be finalised by the end of 2021 with the publication of the updated rules.

The current development deploys detailed energy modelling for new non-residential buildings and the increased use of RES and RES systems, respectively. To support this process, the revised building codes will introduce obligatory (instead of optional) hourly energy calculations for complex non-residential buildings as well as to regulate the quality control of the airtightness of the envelope.

With the publication of the CTE update in Spain in 2013, through the Order of the Ministry of Development 1635, three main changes were made to the previous Technical Code:

• Stricter energy performance requirements were established, increasing the requirements for both public and private buildings.

• The indicator system was modified and adapted to incorporate a new indicator for non-renewable primary energy consumption, which was recommended by European standards for energy performance published in 2008 and 2009.

• The requirements for the contribution of renewable energy sources to buildings were increased. The document increased the requirements for the contribution of renewable energy from solar thermal, and attempted to eliminate the technological barriers that had been detected up to now, which could hinder the implementation of the different renewable generation systems in new construction projects.

The change of RD 732/2019 implies new indicators such as total primary energy consumption, as well as once again increases in regulatory requirements promoting energy efficiency and renewable energies, as established by the Directive on Energy Efficiency of Buildings.

Figure 1. Climatic zones

From 2006 to 2017, Sweden had energy requirements set in the BBR that were continuously tightened to gradually improve the energy performance of new constructions.

In 2015 (BFS 2015:3 BBR 22), the requirements were tightened, and the geographic climatic zones for climate correction (Figure 1) of energy requirements were changed. As an example, see below how the energy performance requirement for an apartment building in Växjö has developed over time:

Table 1. Development of energy performance (kWh/m² A_temp and year) requirement, for apartments buildings over time.

A new method for adjusting to normal use was developed and came into force in December 2016, in Boverket’s Regulations on the determination of the building's energy use during normal use and a normal year, BEN³ (2016:12) (henceforth BEN).

In 2017 (BFS 2017:5 BBR 25), a major change in the requirements was implemented with the introduction of the NZEB definition in Swedish regulations. The system boundaries for energy performance requirements in BBR were changed from measured delivered energy to a primary energy number. The numerical requirements levels were changed, but the change was not intended as a ‘tightening’ of existing requirements levels, but rather comprised a recalculation according to the new system boundaries.

In 2020 (2020:4 BBR 29), changes were made concerning how the primary energy number is calculated, when weighting factors, instead of primary energy factors, were introduced. This revision of the BBR also meant that the requirements for energy performance of buildings were tightened, for most types of buildings. The revised requirement levels were based on the calculation of cost-optimal levels.

Figures 1 and 2 show the simplified historical Building Regulations improvements in England for new residential and new non‐residential buildings. Since 2010, energy standards for new buildings have been strengthened by over 30%. Energy requirements are set as net CO₂ emissions targets (kg CO₂/m².year) and primary energy is also reported. Each new building must have emissions below those of a reference building, which has the same geometry as the actual building, but with standard levels of insulation, systems efficiency, etc. Each type of energy (e.g. gas, electricity) has a different carbon intensity, expressed as kg CO₂/kWh, which reflects the amount of CO₂ emitted to deliver 1 kWh of energy to the building.

The graphs in Figures 1 and 2 are based on the 2006 Building Regulations (the reference) and historical improvements for 2010² and 2013³.

The 2013 Building Regulations set energy performance requirements for new and existing buildings (residential and non‐residential) and came into effect in April 2014. The 2013 Regulations were strengthened to deliver improved CO₂ savings over the previous 2010 Building Regulations of:

• 6% across new residential buildings;
• 9% across new non‐residential buildings.

There are no specific requirements for public buildings.

In 2019, the Government passed legislation to commit the UK to a legally binding target of net zero emissions by 2050⁴. The Grand Challenge Buildings Mission⁵ builds on this legislation to at least halve the energy use of new buildings by 2030.

Within the same year, the Government consulted on changes to Part L (conservation of fuel and power) and Part F (ventilation) of the Building Regulations for new homes in England to ensure the 2050 target is met. The consultation proposes an ambitious uplift in the energy efficiency of new homes through the introduction of the Future Homes Standard from 2025⁶. It is expected that an average home built to the Future Homes Standard will have carbon emissions 75-80% lower than those built to current Building Regulations. Standards such as low carbon heating and good fabric will mean they will be fit for the future.

The Government has also consulted on a meaningful and achievable increase to the energy efficiency standards for new homes. It is anticipated that a two-stage approach to implementing the Future Homes Standard will help to prepare the necessary supply chains by encouraging the use of low-carbon heating in new homes, while accounting for the skills of industry and market factors. The Government will publish its response to the Future Homes Standard consultation in due course.

The UK Government will keep energy efficiency standards under review. Cost effectiveness/ cost optimality is regularly assessed and informs whether any strengthening of standards is required. The Government plans to consult further in due course, proposing improvements to the energy efficiency standards for new non-domestic buildings.

Figure 1: New residential Building Regulations (England), historical improvements.

Figure 2: New non-residential Building Regulations (England), historical improvements.

Figures 1 and 2 show simplified historical Building Regulations improvements in Wales for new buildings. The graphs are based on the 2006 Regulations (the reference year), historical improvements for 2010 and 2014, and Government announcements for 2017 and 2020. Note that the 2006 and 2010 Regulations applied across England and Wales, whereas the 2014 Regulations apply to Wales only, following the devolution of powers to the Welsh Government in 2011.

The 2014 amendments to the Building Regulations set energy performance requirements for new and existing buildings¹. The Regulations were strengthened to deliver improved CO₂ savings over the previous Regulations i.e., 8% across new residential buildings and 20% across new non-residential buildings. Changes to existing building requirements were also introduced in 2014. There were also 2016 amendments to clarify the application of the approved calculation methodology².

In 2019, the UK Government passed legislation to commit the UK to a legally binding target of net zero emissions by 2050³.

Within the same year, the Welsh Government consulted on the changes to Part L (conservation of fuel and power) and Part F (ventilation) of the Building Regulations for new residential buildings. Within the consultation, the Government outlined their vision of the future Part L for 2025. This vision includes high fabric standards, a higher specification for glazing, and the use of heat pumps, heat networks, direct electric heating and/ or other technologies⁴.

A review of the Building Regulations’ energy performance requirements (“Part L”) is ongoing. This review will be informed by further consultation and, as a minimum, it will aim to improve energy requirements where necessary to deliver NZEB standards at a cost optimal level or better for all building types, with amendments to the Building Regulations expected to come into force in late 2021/ early 2022. The review will also develop proposals to implement the 2018 amendments to the EPBD (2018/844).

Figure 1. New residential Building Regulations improvements, Wales.

Figure 2. New non-residential Building Regulations improvements, Wales.

Northern Ireland implements the EPBD energy performance requirements through Part F “Conservation of Fuel and Power”² of the Building Regulations. Amendments to Part F in 2012 followed England’s Regulations and guidance, and implemented a performance uplift of 25% on previous standards (Figures 1 and 2). Minor amendments were introduced in 2014³ and 2016⁴ to comply with, or to help clarify, other EPBD requirements. Department of Finance (DoF) issued an information note on the application of nearly zero-energy buildings (NZEB) in relation to new buildings owned and occupied by public authorities in 2019⁵, clarifying that public procurement policies together with the existing building regulatory regime are sufficient to meet the NZEB requirements. During the same year, the UK Government passed legislation to commit the UK to a legally binding target of net zero emissions by 2050.⁶

As Northern Ireland Building Regulations are normally updated in light of amendments made in England, DoF is working to update the current technical guidance with a view to the English Building Regulations amendment proposals.

Figure 1. New domestic Building Regulations improvements, Northern Ireland.

Figure 2. New non-domestic Building Regulations improvements, Northern Ireland.

Minimum energy performance requirements, for new buildings and new work to existing buildings, are set in the Building Regulations. These regulations were reviewed and improved most recently in October 2015 (Figures 1 and 2) based on percentage CO₂ emissions reductions (2002 regulations are the reference). Technical Handbooks^{2 3} provide guidance on achieving compliance with the regulations.

Building Regulations were amended in 2016⁴ to transpose dates for nearly zero energy new buildings set out under Article 9(1). A review of the energy standards commenced in 2018 with a ‘call for evidence’⁵ to investigate where further improvement can be made in the energy performance of new buildings. Consultation and publication of improved standards is programmed for 2020/21.

The UK Government has assessed current minimum energy performance requirements in Building Regulations across the UK against the cost-optimal levels as required under Article 5 of the Directive. Following this assessment, it was concluded that EPBD requirements for ‘nearly zero energy’ new buildings are, at this time, met by the minimum energy performance requirements set by current Building Regulations.

In 2019, the Scottish Government passed legislation to amend its previous 2009 Climate Change Act and commit to a legally binding target of net zero emissions by 2045⁶.

Figure 1. New domestic Building Regulations improvements, Scotland.

Figure 2. New non-domestic Building Regulations improvements, Scotland.