1. Kees Arkesteijn ISSO/the Netherlands k.arkesteijn@isso.nl
ENERGY PERFOMANCE CERTIFICATES EN "Energy performance of buildings – Methods for expressing energy performance and for the energy certification of buildings"
Kees Arkesteijn
ISSO/the Netherlands
The European Commission gave mandate 343 to CEN for the elaboration and adoption of a European methodology to calculate the integrated energy performance of buildings in accordance with the requirements of the Energy Performance of Buildings Directive (EPBD).
Access to such a calculation methodology in the form of European Standards makes it possible to coordinate the various measures for improving the energy efficiency in buildings between the Member States.
It will increase the accessibility, transparency and objectivity of the energy performance assessment in the Member States.
This paper describes how these European standards (published in 2007 and 2008) could be progressively integrated in the existing national buildings regulations in order to converge towards a common European calculation method of the integrated energy performance of buildings.

2. Outline The EU CENSE project. EPBD requirements.
Methods for expressing the Energy performance.
References values.
Certificate shape.
Conclusion and Outlook.

3. The EU CENSE project (Oct. 2007 - March 2010)
Aim of the project:
To accelerate adoption and improve effectiveness of the EPBD related CEN- standards in the EU Member States.
These standards were successively published in the years and are being implemented or planned to be implemented in many EU Member States. However, the full implementation is not a trivial task.
Main project activities:
To widely communicate role, status and content of these standards; to provide guidance on the implementation;
To collect comments and good practice examples from Member States aiming to remove obstacles;
To prepare recommendations to CEN for a “second generation” of standards on the integrated energy performance of buildings.

4. Brief introduction
A brief introduction to the CENSE project and the CEN-EPBD standards is provided in a separate presentation:

5. More information More information and downloads: www.iee-cense.eu
Disclaimer:
CENSE has received funding from the Community’s Intelligent Energy Europe programme under the contract EIE/07/069/SI
The content of this presentation reflects the authors view. The author(s) and the European Commission are not liable for any use that may be made of the information contained therein.
Moreover, because this is an interim result of the project: any conclusions are only preliminary and may change in the course of the project based on further feedback from the contributors, additional collected information and/or increased insight.
More information on EN standard context and CENSE project can be found in the document “Background, status and future of the CEN standards to support the Energy Performance of Buildings Directive (EPBD)”

6. EPBD requirements
Article 7 of the EPDB ( 2002/91/EC) stipulates the information that an energy certificate must contain
The certificate is available when the building is constructed, sold or rented out.
Buildings > 1000 m2 usable floor area:
Occupied by public authorities;
Institutions providing public services to a large number of person
must have a certificate placed in prominent place, clearly visible for public.
The certificate shall include:
Reference values;
Recommendations for cost-effective improvements.
The EPBD asks for a methodology to assess the integrated energy performance of buildings.
At this time only few European countries already had a methodology to take into account the effect of the necessary technical systems (heating, dhw…) and no international standard was available on this topic.
The EPBD directive only establish some requirements to the calculation methodology, which are listed in the annex of the Directive.
In order to get a more harmonised approach, the European Commission, DG TREN and DG Enterprise, gave the mandate 343 to CEN for the elaboration and adoption of a calculation methodology of the integrated energy performance of buildings in accordance with the terms set forth in Directive 2002/91/EC (Energy Performance of Buildings Directive-EPBD). Access to such a calculation methodology in the form of European Standards makes it possible to coordinate the various measures for improving the energy efficiency in buildings between the Member States. It will increase the accessibility, transparency and objectivity of the energy performance assessment in the Member States (as mentioned in recital (10) of the EPBD).
Having different methodologies in the European countries is practically a new barrier to the exchange of products and services:
it is difficult for a professional to work in a different country if he has to learn a new method
software market is limited, small countries may lack the necessary calculation tools
products have to be tested and/or qualified separately for each country, since the input data may be not the same
So availability a common calculation method is an essential requirement to get a true common market of products and services in the building and related technical services field.
The CEN standards developed under mandate 343 were published in 2007 and 2008 and are now available.

7. Definition Energy performance
The energy performance of a building is the amount of energy actually consumed or estimated to meet the different needs associated with a standardised use of the building ….
reflected in one or more numeric indicators.
The starting point for a smooth convergence could be to adopt the same overall calculation structure and to start by connecting the existing national methods (or parts of it) to this common general structure. National methods could then be gradually be replaced by the appropriate CEN standards and the related national annexes.
The general structure is defined in the standard EN 15603 "Energy performance of buildings - Overall energy use and definition of energy ratings". The general structure defined in EN 15603 summarises the main parameters of the energy performance of buildings. The same parameters are required by the EPBD.
The results of the energy performance calculations can be obtained either by simplified methods or by more detailed methods. This has the advantage that the same structure can be used for different issues, e.g. for the assessment of single family houses and/or commercial buildings, for energy performance certificates and/or for checking compliance with minimum energy performance requirements, for new and/or existing buildings.

8. Methodology The methodology shall include at least:
Building shell (thermal properties, position, orientation, passive solar systems etc);
Technical Building systems and uses (HVAC- installation, hot water supply, built-in lighting);
Positive influence innovative systems (active solar-systems, renewable energy sources, electricity procuded by CHP;
Large scale systems (district or block heating).
The CEN standards are structured by modules starting from the product characteristics until and including the overall energy uses described in EN  This "going through" approach is very important in order to maintain the links between product testing and system evaluation, as the product is not longer evaluated as such but as part of a system.
The standards dealing with product characteristics (example: thermal properties of materials, appliance testing…) are the first level.
The standards dealing with building energy needs are the second level. Heating, cooling, lighting, ventilation and domestic hot water needs are taken into account. This part of the calculation deals with the building only, without consideration of any technical system. Losses and gains are taken into account.
The standards dealing with the technical systems are the third level. From the building needs you get the energy use of the technical systems (sorted by energy carrier) to fulfil the building energy needs
The top level EN 15603 collects the results of the calculation of the relevant energy uses (heating, cooling, lighting, ventilation and domestic hot water) and converts them into one or more numeric indicators (primary energy, CO2 emissions, cost…).
EN 15603 defines the boundaries of the calculation (“the system boundaries”), comprising the building energy needs and the energy used (and optionally: produced) by the technical building systems, including their interactions. It also defines the different types of energy flows entering and/or leaving the system boundaries.
EN also deals with possible interactions between buildings and technical systems, such as system losses recovery.
Finally, EN defines minimum requirements to reporting.

9. Methods for expressing the Energy Performance
Building Need
Building Need
EN provides methods that are required to express the energy performance (EP) of buildings:
Based on measured rating; or
Based on calculated rating;
Indicator EP based on EN
EN ISO 13790
EN ISO 13790
Emission & control
Emission & control
EN 15316
EN 15316 - - 2 2 - - 1 1
Distribution
Distribution
EN 15316
EN 15316 - - 2 2 - - 3 3
Generation
Generation
EN 15316
EN 15316 - - 4 4 - - xx xx
Primary Energy
Primary Energy
EN 15603
EN 15603
EN 15603 defines the general structure and highlights the basic steps (connecting points for the calculation) of the building/systems energy balance as follows:
Building energy needs (heating, cooling, lighting, ventilation and domestic hot water);
Input to all distribution systems (these are the required outputs of generation systems)
This part deals with technical systems without the generation part. Losses and auxiliary energy needs are taken into account;
Generation systems energy input (energy use) This part deals with the generation systems. The result is the delivered and exported energy, sorted by energy carrier;
Calculation of ratings (weighted energy ratings); The delivered and exported amounts of energy carriers are weighted (using appropriate conversion factors) and summed. This takes into account everything that happens outside the building.
Reporting.
The calculation direction in EN 15603 goes from the needs to the source, e.g. from the building energy needs to the weighted delivered/exported energy carriers (such as primary energy as shown in the example for space heating). It follows the opposite direction of the physical energy flow in a building. Electrical services (such as lighting, ventilation, auxiliary) and thermal services (e.g. heating, cooling) are considered separately inside the building boundaries.
Energy performance
EN 15217

10. Methods for expressing the Energy Performance
The certificate at least contain:
Global indicator (easy-to-understood) of the energy consumption of the certified building.
The certificate can also contain:
Primary energy;
CO2 emmissions;
Total energy cost;
Sum of the net delivered energy weighted by any other parameter (defined by national energy policy);
Conditioned area.
EN 15603 defines the general structure and highlights the basic steps (connecting points for the calculation) of the building/systems energy balance as follows:
Building energy needs (heating, cooling, lighting, ventilation and domestic hot water);
Input to all distribution systems (these are the required outputs of generation systems)
This part deals with technical systems without the generation part. Losses and auxiliary energy needs are taken into account;
Generation systems energy input (energy use) This part deals with the generation systems. The result is the delivered and exported energy, sorted by energy carrier;
Calculation of ratings (weighted energy ratings); The delivered and exported amounts of energy carriers are weighted (using appropriate conversion factors) and summed. This takes into account everything that happens outside the building.
Reporting.
The calculation direction in EN 15603 goes from the needs to the source, e.g. from the building energy needs to the weighted delivered/exported energy carriers (such as primary energy as shown in the example for space heating). It follows the opposite direction of the physical energy flow in a building. Electrical services (such as lighting, ventilation, auxiliary) and thermal services (e.g. heating, cooling) are considered separately inside the building boundaries.
slide 10 10

11. Reference values
Reference values shall be defined for classes of buildings with different functions.
Classes of buildings:
Single family houses, appartment blocks, office buildings, eductional buildings, hospitals, hotels and restaurants, sportsfacilities, wholesale and retail trade service buildings.
Functions :
Services that are required( HVAC, domestic hot water);
Different specifications for internal climate and occupant densities and occupancy schedules.
The calculation starts with the building energy needs. The values related to the building energy needs are collected in table 4 of EN 15603.
In national building regulations the values in table 4/EN 15603 can be determined by national methods or ideally by EN standards (such as ISO EN 13790). The values shown in EN 15603 are annual values. They can be calculated by simplified methods (e.g. monthly calculation step) or detailed methods (e.g. hourly calculation step). The values shown in these tables are the sum of the values of each calculation interval (i.e. the sum of the 12 monthly values …)
Elements having a major effect on the building energy needs such as thermal insulation, glazing, etc., should be taken into account.
slide 11 11

12. Energy classes
EN indicates that the energy certificate may contain energy classes:
Range from A to G.
Range A: buildings of highest energy performance.
Range G: buildings of lowest energy performance.
The current legal status shall be placed at the boundary between classes B and C, while the building stock reference shall be placed at the boundary between classes D and E.
The calculation starts with the building energy needs. The values related to the building energy needs are collected in table 4 of EN 15603.
In national building regulations the values in table 4/EN 15603 can be determined by national methods or ideally by EN standards (such as ISO EN 13790). The values shown in EN 15603 are annual values. They can be calculated by simplified methods (e.g. monthly calculation step) or detailed methods (e.g. hourly calculation step). The values shown in these tables are the sum of the values of each calculation interval (i.e. the sum of the 12 monthly values …)
Elements having a major effect on the building energy needs such as thermal insulation, glazing, etc., should be taken into account.
slide 12 12

13. Certificate shape
EN offers 3 examples of the certificate layout:
Certificate including a calculated rating and energy classes;
Certificate includes a calculated and measured rating;
Certificate including a continuous scale instead of energy classes.
Examples of certificates
The calculation then continues with the part related to the technical building systems.
In EN the calculation of technical systems is divided into two steps:
Technical system without building generation devices Losses, auxiliary energy needs and recovery are taken into account here. The result is the required input of the distribution systems, that is also the required output of generation systems, see below;
Energy generation systems (energy use) The input is the required input of distribution systems. Priority of generation systems is taken into account here. The result is the delivered and exported energy, sorted by energy carrier;;
Technical system thermal losses, electrical and auxiliary energy without building generation devices
The values related to the technical system thermal losses, electrical and auxiliary energy, taking into account emission, control and distribution, without building generation devices, are collected in table 5/EN  The values in table 5/EN can be calculated according to available national methods or issued by tables like the following.
EN defines that for each sub-system, simplified (e.g. tabulated values) and/or detailed methods may be applied according to the required accuracy and the available data.
Different levels of details may be used for the different sub-systems of the heating system. However, it is essential that the results correspond to the defined output values of the sub-system in order to ensure proper links to calculations for the following sub-systems and development of a common structure.
The example shown is an hypothetical simplified national table stating that losses are a fixed value in kWh/m² according to the system type. This will be connected to the general structure of EN in the next slide.

14. Conclusion and Outlook
CEN worked out a complete, consistent and flexible approach, from the product standard to the overall energy use.
EN gives the methods for expressing energy performance and for energy certification of buildings.
Adopting EN in national building regulation is the first step towards an European way of expressing the Energy Perfomance on the certificate.
The example before has shown that the general structure defined in EN 15603 is:
well structured with defined inputs and outputs;
simple, complete and consistent, starting from the product standards until and including the overall energy use;
 flexible, because only the method is standardised. The method can be parametered at national level by national annexes. Simplified and detailed methods can be used, because different uses require different methods.
The general structure can gradually be filled in by the Member States:
as a first immediate step, with national methods;
then, with CEN standards (with or without national annexes).
It is also possible to mix up CEN standards for some modules and national methods for other modules. For example for the energy generations systems different CEN standards are available . If a Member State prefers, for the time being, to use national methods, the CEN standards can be replaced by national methods but the national method must provide the standardised outputs of the CEN standards in order to be integrated in the general approach.

15. More information More information and downloads: www.iee-cense.eu
Disclaimer:
CENSE has received funding from the Community’s Intelligent Energy Europe programme under the contract EIE/07/069/SI
The content of this presentation reflects the authors view. The author(s) and the European Commission are not liable for any use that may be made of the information contained therein.
Moreover, because this is an interim result of the project: any conclusions are only preliminary and may change in the course of the project based on further feedback from the contributors, additional collected information and/or increased insight.