Yes. The Directive states that: "The certificate shall be accompanied by recommendations for the cost-effective improvement of the energy performance."

Author: JC VISIER (CSTB) Date: 04/04/2006

This can be done but it is not mandatory. The choice is left to Member States.

Specifically, the Directive states in Article 3 that "The energy performance of a building shall be expressed in a transparent manner and may include a CO₂ emission indicator".

Author:   JC VISIER (CSTB)
Date:   04/04/2006

Yes. Public buildings require an energy performance certificate not older than 10 years old and the certificate shall be visible to the public in these buildings. Specifically, Article 7.3 of the Directive states that:

"Member States shall take measures to ensure that for buildings with a total useful floor area over 1 000 m2 occupied by public authorities and by institutions providing public services to a large number of persons and therefore frequently visited by these persons an energy certificate, not older than 10 years, is placed in a prominent place clearly visible to the public."

Author:   JC VISIER (CSTB)
Date:   04/04/2006

Member States may exclude the following types of buildings from certification (Article 4):

• "buildings and monuments officially protected as part of a designated environment or because of their special architectural or historic merit, where compliance with the requirements
• would unacceptably alter their character or appearance,
• buildings used as places of worship and for religious activities,
• temporary buildings with a planned time of use of two years or less, industrial sites, workshops and non-residential agricultural buildings with low energy demand and non residential agricultural buildings which are in use by a sector covered by a national sectoral agreement on energy performance,
• residential buildings which are intended to be used less than four months of the year,
• stand-alone buildings with a total useful floor area of less than 50 m2."

Author:   JC VISIER (CSTB)
Date:   04/04/2006

All buildings which are constructed, rented or sold out require an energy performance certificate (Article 7(1)).

The production of a certificate does not generally depend on the type or size of the building.

Furthermore Member States may exclude some types of buildings as stated in article 4(3).

Author:   JC VISIER (CSTB)
Date:   04/04/2006

Article 8 of the EPBD offers two options:

1. either inspection of boilers (8.a) or
2. provision of advice to the users that must achieve an overall equivalent impact to that of inspection (8.b).

The first option (inspection of boilers) requires regular inspection ofÿboilers fired with non-renewable liquid or solid fuelÿof an effective rated output of 20 to 100 kW and inspection of boilers of an effective rated output of more than 100 kW without restriction about the fuel used.

The Directive also states that regular inspection of boilers from 20 to 100 kW may apply to fuels other than non-renewable liquid or solid fuels.

Regular inspection of boilers is therefore not compulsory for all types of fuels or all rated outputs, especially as an alternative (but equivalent) approach is allowed.

Author:  François DURIER (CETIAT)
Date:   04/04/06

If a Member State chooses to implement inspection of boilers (by referring to article 8a), the following requirements should apply to wood-fired boilers:

• regular inspection of wood-fired boilers with a rated output of more than 100 kW at least every two years,
• one-off inspection of the whole heating installation with wood-fired boilers of more than 20 kW rated output which are older than 15 years.

The Member State may also require regular inspection for wood-fired boilers between 20 and 100 kW.

Author:  François DURIER (CETIAT)
Date:   04/04/06

The frequency of inspection of air conditioning systems is not specified in the Directive. It is up to the Member States to specify and implement.

Author:  Michèle MONDOT (CETIAT)
Date:   24/03/06

The definition of air-conditioning systems in article 2 of the EPBD (“a combination of all components required to provide a form of air treatment in which temperature is controlled or can be lowered, possibly in combination with the control of ventilation, humidity and air cleanliness”) refers to the whole system where the temperature of the air can be cooled, clearly including, therefore, its distribution and control systems.

EN standard 15240 (“Guidelines for inspection of air-conditioning systems”) includes specific items covering inspection of the distribution system and the controls of air-conditioning systems.

However, the details of the inspection procedure are fixed by each Member State and, therefore, different requirements may be found in different Members States.

Author:  Eduardo MALDONADO (University of Porto, Portugal)

Date:   27/11/07 

The definition of air-conditioning systems in article 2 of the EPBD (“a combination of all components required to provide a form of air treatment in which temperature is controlled or can be lowered, possibly in combination with the control of ventilation, humidity and air cleanliness”) refers to the whole system where the temperature of the air can be cooled. If that system also includes a heating mode, which is quite common, the heating component is just one more component of the whole system and, according to article 9 of the EPBD, the air-conditioning system (as whole) should be inspected. However, the details of the inspection procedure are fixed by each Member State. Thus, national procedures for inspection of air-conditioning systems may specify which components of the air-conditioning system must be inspected and how often and with which methodology that inspection is to be carried out, including, or not, the specific configuration when it operates in a heating mode. EN standard 15240 (“Guidelines for inspection of air-conditioning systems”) deals exclusively with “cooling” components and issues. Procedures for inspecting heating systems, including boilers and heat distribution systems, e.g., ventilation systems, are described in EN 15378.

Author: Eduardo MALDONADO (University of Porto, Portugal) Date: 27/11/07

If a ventilation system has no thermal component, i.e., if it strictly serves only the purpose of providing fresh air to guarantee a suitable indoor air quality, the EPBD requirement for inspections does not apply. The same applies for ventilation systems where the inlet air is only heated (e.g., when the outdoor air is too cold and would cause discomfort to the occupants or the possibility for formation of frost or condensate if brought inside the building untreated).

However, if the fresh air provided by the ventilation system can also be cooled before delivery to the occupied spaces, then these ventilation systems are, in reality, air-conditioning systems, in accordance with the definition of air-conditioning systems in article 2 of the EPBD (“a combination of all components required to provide a form of air treatment in which temperature is controlled or can be lowered, possibly in combination with the control of ventilation, humidity and air cleanliness”) and, as such, they are required to be periodically inspected, according to article 9 of the EPBD, if the cooling power is larger than 12 kW.

Author:  Eduardo MALDONADO (University of Porto, Portugal)
Date:   27/11/07

 The EPBD requires (article 9) that “Member States shall lay down the necessary measures to establish a regular inspection of air-conditioning systems of an effective rated output of more than 12 kW.”

The text in the first paragraph is ambiguous as it allows several interpretations: whether the effective rated (thermal) output of 12 kW (above which inspection is required) relates to one air-conditioning unit or to the sum of all units in one building, or even to the sum of all units in one building that are owned by the same owner.

It is possible to find Member States who have adopted any one of these different interpretations in the transposition, and they all seem to be strictly correct from a legal point of view. Each interpretation has its own advantages, and MS adopted the alternative that they considered most applicable to the local market conditions.

Limiting inspections to individual units above 12 kW reduces the number of inspections to be carried out. The cost of inspecting smaller units is usually large compared to the expected energy savings, and the cost-effectiveness of these inspections may be questionable. Moreover, fewer inspections mean the need for fewer inspectors, and their lack of availability is one of the main bottlenecks for implementing this EPBD requirement.

Requiring inspections for all units in a building (or owned by the same owner in a building) when the total installed AC capacity is above 12 kW cuts the loop-hole whereby an owner needing, e.g., 20 kW of AC opts to install two smaller, but less efficient, 10 kW units just to avoid inspections. This approach promotes installation of larger more efficient units, avoiding the proliferation of smaller units which also potentially have a non-negligible visual impact.

However, the same article 9 goes on to specify that “This inspection shall include an assessment of the air-conditioning efficiency and the sizing compared to the cooling requirements of the building”. So, if one space is served by more than one AC unit, the EPBD seems to indicate that the inspection must really cover all the units simultaneously, as otherwise it will be impossible to give advice about the sizing of any individual unit without carrying out a global analysis.

Author:  Eduardo MALDONADO (University of Porto, Portugal)
Date:   27/11/07

The categories of buildings listed in Article 4, paragraph 3, for which Member States may decide not to set or apply minimum energy performance requirements, do only relate to Article 4, paragraph 1, and not to the inspection of boilers (Article 8) and air conditioning systems (Article 9).

The cases in which inspection of boilers and air conditioning systems could not be required are listed below:

In Member States that choose option (a) of Article 8 (regular inspection of boilers and one-off inspection of heating installation with boilers older than 15 years), buildings that use energy to condition the indoor climate could be exempted from the requirements of Article 8 if they use no boiler of an effective rated output of more than 20 kW fired with non renewable.

Member States that choose option (b) of Article 8 (provision of advice to the users) could decide that some boilers or buildings are not covered by the measures that they implement, provided that they show to the Commission that the overall impact oftheir approach is broadly equivalent to that arising from the provisions set out in option (a).

Buildings in which energy is used to condition the indoor climate cannot be exempted from the requirements of Article 9 (inspection of air conditioning systems) except if they do not use an air conditioning system of an effective rated output of more than 12 kW.

Author:  Francois DURIER (CETIAT)
Date:   16/12/08

Each Member State is applying different qualification criteria.

Article 10 of the EPBD suggests that practitioners must be "qualified and/or accredited experts".  This implies that no specific formal qualification is required if the Independent Expert is "accredited".

Since the accreditation requirements are not defined in the EPBD, each Member State is likely to establish different criteria for the accreditation of Independent Experts.  This may, or may not, include proof of competence by examination and/or the development of new nationally recognised qualifications.

If proof of competence to become an "accredited expert" is to be based on a qualification/examination, up to seven separate qualifications may be required, including:-

1. Certification of new domestic buildings.
2. Certification and drafting accompanying report for existing domestic buildings.
3. Certification of new non-domestic buildings.
4. Certification and drafting accompanying report for existing non-domestic buildings.
5. Certification and drafting of report for public buildings for display purposes.
6. Boiler plant inspection and reporting.
7. Air conditioning plant inspection and reporting.

Author:  David STRONG (BRE)
Date:   22/03/06

Provided Member States establish regulated competent person schemes which "accredit" experts on the basis of objective criteria with formal quality assurance checks and procedures (ISO 17024  and ISO 9001) the risks and liabilities associated with undertaking building certification and plant inspection should be low, (since obtaining Professional Indemnity (PI) Insurance should be cost-effective).

However, if Member States do not introduce formal qualification and/or accreditation requirements it is likely that building certification and plant inspection will be undertaken by unqualified practitioners operating outside any formal quality assurance framework.  In this instance, PI insurance may be difficult (or impossible) to obtain at a realistic cost.  This will result in major (potentially uninsurable) liabilities for building certifier and/or plant inspectors.

Author:  David STRONG (BRE)

Date:   22/03/06 

If the EPBD is to achieve its objectives, it is of considerable important that prospective building purchasers or tenants are able to have confidence in energy performance certificates, plant inspection and the accompanying reports and recommendations.

Major investment decisions and property transactions will be based upon recommendations made by the EPBD Independent Experts.  There are important issues of consumer protection and a major risk of fraud if the requirements of Articles 7, 8 and 9 are not undertaken in an independent manner.

Furthermore, Section 10 of the Recitals to the EPBD states that calculating the energy performance of buildings must be "carried out by qualified and/or accredited experts, whose independence is to be guaranteed on the basis of objective criteria".  Recital 10 also states that "This will contribute to a level playing field as regards efforts made in Member States to energy saving in the buildings sector and will introduce transparency for prospective owners or users with regard to energy performance in the community property market".

Author:  David STRONG (BRE)

Date:   22/03/06 

Different Member States are interpreting the definition of "in an independent manner" in various ways.

Some Member States are defining this requirement as requiring building certification and/or plant inspection to be undertaken by a person who is entirely independent of the building owner or occupier.

An alternative approach being adopted in some Member States allows "self-certification" by an accredited expert directly employed by the building owner or occupant. 

In most cases self-certification is being linked to a government endorsed quality assurance accreditation framework so as to ensure that self-certification is only undertaken by suitably qualified "competent persons".

Author:  David STRONG (BRE)
Date:   22/03/06

Article 10 of the EPBD states that "Member States shall ensure that the certification of buildings, the drafting of the accompanying recommendations and the inspection of boilers and air conditioning systems are carried out in an independent manner by qualified and/or accredited experts, whether operating as sole traders or employed by public or private enterprise bodies".

The minimum requirement for Independent Experts is to be "accredited" by a Member State as competent and to operate in a manner which guarantees independence, based upon objective criteria.

Author:  David STRONG (BRE)
Date:   22/03/06

Choices have to be made at the national level. In several countries this is or will be done, at least for the time being, in a practical way, by copying the relevant parts of EN ISO 13790 as national standard, adding further specifications. (See CENSE Information Paper P90 on the practical use of CEN standards which can also be downloaded from the BUILD UP Portal).
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 21/10/2008

If an ISO (International Organization for Standardization) standard is also an EN ISO standard, then it is a European standard just like any other EN (European) standard. As illustrated in several CENSE Information Papers, e.g. P92 or P94, a CEN standard to support the EPBD is one of a series of standards, which are mutually related and serve particular European (EPBD) needs; in particular: which are meant to be applied in the context of national building regulations. If, for this purpose, such an EN ISO standard needs to make a reference to another EN standard, then one may find in the standard a distinction between references to EN standards for use within the CEN area and references to ISO or national standards for use outside Europe.
In EN ISO 13790, for instance, this was solved by concentrating all references to other standards in one normative annex (Annex A), which provides for the "CEN area": references to CEN (EN or EN ISO) standards and for "elsewhere": references to ISO standards or, in absence of ISO standards, to national standards (see CENSE Info Paper P92 which can also be downloaded from the BUILD UP Portal).

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands) and Brian Anderson, BRE (UK)
Date: 2009/02/19

Yes, but some of the required input data may not be available at reasonable costs. For those cases default values may be provided at national level, e.g. as function of type and age of construction.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands) and Brian Anderson, BRE (UK)

Date: 2009/02/19

Heat is lost from a building or building part by transmission or ventilation, as a result of a positive temperature difference between the indoor and outdoor (or other) environment. However, if the indoor temperature of the considered building or building part is lower than the temperature of the other environment (outdoor environment or another building part), the heat loss becomes negative. Therefore the more neutral term “heat transfer” was introduced from the 2007 versions of the EPBD related standards on. The downside of this is, that now it must be explicitly stated which direction has the positive sign. By definition, if the heat flows from the considered building or building part to the other environment, it has a positive sign.
NOTE: a negative heat loss should not be confused with “heat gain”. The term heat gain (see e.g. EN ISO 13790, energy use for heating and cooling) is used for solar and internal gains which are not a function of the indoor-outdoor temperature difference: if the indoor temperature rises, e.g. due to excess gains, the heat transfer by transmission and ventilation will automatically rise proportionally, but the solar and internal heat gains remain the same (compare the electric equivalent: a current through a resistor versus a current source).

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands) and Brian Anderson, BRE (UK)
Date: 2009/02/19

National documents define under which conditions the two methods are to be applied. The choice of method depends on several aspects. First the purpose of the assessment should be considered, as it influences the level of detail required. The type and complexity of the building and its technical system are also relevant parameters. In general, the holistic approach is applied for complex systems and when a high level of detail is required.
More information: CENSE Information Paper P095 which can also be downloaded from the BUILD UP Portal.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Anna Staudt and Hans Erhorn, Fraunhofer Institute of Building Physics (Germany)
Date: 2008/02/04

No, it will not lead to the same energy performance rating in each Member State.

Regional differences in climate, building tradition and user behaviour in Europe will have an impact on the input data and consequently on the energy performance.
The standards developed to support the practical implementation of the EPBD have to be flexible enough to accommodate these differences, both in the (national) choice between different options provided in the CEN standards, and in the (national) choice of input data and boundary conditions. See also the question on the status of the EPBD related CEN standards.

Author:  Dick van DIJK (TNO)
Date:   14/04/06

All CEN standards (EN or EN-ISO) and draft standards (prEN or prEN-DIS) can be ordered from the National Standards Body organisation (NSB) (see www.cen.eu).
All EPBD CEN standards were published in 2007 or 2008, as EN or EN-ISO standards.
The total set contains 2000 pages. As usual, EN’s are published in English and, by choice of DIN and AFNOR, also published in a German or French version. It is up to the other NSB’s to decide if national language versions will be produced, depending on the target group as explained under the question: "Are CEN standards only available in English?".
Author: Dick van DIJK (TNO)
Answered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 2008/03/10

There is an agreement between CEN and ISO saying that they shall not work on the same Work Items. New work can only be started in CEN if it is not already on the ISO program and vice versa.

CEN-Technical Committees are encouraged to seek contact with related ISO-Technical Committees to agree on possible parallel voting. This means that the European standard (EN) may become a combined CEN-ISO standard (ISO-EN) if accepted by ISO.

Existing ENs will by preference be maintained by related ISO-Technical Committees. Only when related ISO-Technical Committees are not interested or not giving it enough priority, will the CEN-TC continue the normal 5 years maintenance schedule or faster if needed.

Author:  Dick van DIJK (TNO)
Date:   14/04/06

There is an agreement between CEN and the national standards bodies (NSBs) that CEN standardisation work shall be considered before starting national standardisation work. If CEN work is already started, this line shall be followed and national work should not be done. It is called a "Stand still". After the ENs are published, existing and possibly conflicting national standards shall be withdrawn within a certain time frame. If national legislation is referring to these national standards, the NSB can get some years to repair this. A three to five years period is considered as the maximum deviation period in which national standards shall be withdrawn.

Note, however, that in some Member States the building regulations do not always refer to national standards, but e.g. have (part of) the assessment procedures included in the regulations. In the case of the Construction Products Directive, the European Commission issues mandates to CEN to make use of CEN standards mandatory for all Member States. The EPBD allows a national/regional differentiation. See also the question on the status of the EPBD related CEN standards.

Author:  Dick van DIJK (TNO)
Date:   14/04/06

CEN standards (ENs) or draft CEN standards (prENs) and combined EN-ISO standards are officially published by CEN in Brussels but can only be obtained from the so called National Standards Bodies (NSBs). The CEN website (www.cenorm.be) provides the contacts and also has a search engine to see which standard activities are in progress and which existing and draft standards are available. 

Author:  Dick van DIJK (TNO)
Date:   14/04/06

CEN is the European Association of national standardisation institutes, the so called National Standards Bodies (NSB’s). These NSB’s are responsible for the contact with the interested market parties and experts preparing the CEN standards in the same way they do when preparing national standards. Members of CEN-Technical Committees (CEN-TC’s) are nominated by the NSB’s. The TC’s decide on the scope and content of a standard. The actual work is done in smaller CEN-TC-Working Groups whose expert members are nominated by NSB’s. In most countries the NSB organises a national mirror group to monitor and support the work of a CEN-TC. This was also done in the EPBD program of CEN. Because in this case the work covers 5 CEN-TC’s, some NSB’s organised a special mirror group to follow the work on the total EPBD CEN program.
Members who participate to CEN-TC-WG’s are involved in the details of the standard development. They should contribute themselves, as expert, and be motivated to find the right expertise in their own network.
Once a draft standard is approved by the responsible CEN-TC, it goes out as draft standard (“prEN”) for Public Enquiry. The comments are prepared via the NSB’s. The working group prepares the replies to the comments and prepares a new draft standard which, once approved again by the CEN-TC goes out as final draft for Final Vote. The time between publishing the prEN and publishing the final standard is usually between 21 and 30 months.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 10/03/2008

In the framework of EPB regulations, an innovative system/technology is defined as a system/technology:

· that in most cases gives a better EPB performance than the common systems/technologies and,

· whose performance cannot be assessed by the standard EPB calculation procedure.

According to the definition mentioned here above, a glazing unit with a very low thermal transmittance (e.g. U-value = 0.3 W/m²K) is not an "innovative technology" if the procedure in the EPB regulation is based on EN 673, because this standard allows the calculation of such U-value – independently of the fact that this glazing can be very innovative from a technical point of view. On the other hand, an electrochromic glazing is an innovative technology if the EPB method foresees no procedure for handling the fact that the properties of this glazing vary with time. This will probably be the case because there is currently no CEN standard to estimate the energy performances of such glazing on an annual basis.

It is important to note that, according to the above definition, a technology can be considered as innovative in one Member State and not in another. For instance, ventilation systems based on humidity control are integrated in the French basis procedure of EPB regulation; they are therefore not considered in France as innovative systems whereas they will be considered as such in most of the other European countries.

More information can be found in the final report of the SAVE ENPER project (see: www.buildingsplatform.eu/cms/index.php or www.enper.org) which will be made available by the SAVE ASIEPI project, started in October 2007 (www.asiepi.eu – coming soon).

Author:  Nicolas Heijmans (BBRI)
Date:   14/01/08

There are several reasons why there is not just one CEN standard covering all EPBD aspects. The two main reasons are:

1. The CEN standards cover different types, with different application areas and different target groups, ranging from building designers and inspectors to specific specialists on building physics or systems (lighting, ventilation, cooling, heating, hot water, ..).
2. CEN didn't start this work from scratch. The short timescale and pre-existing drafts (from 5 CEN Technical Committees, each covering a specific field of expertise) have resulted in more fragmentation than if started from scratch. On the other hand, starting from scratch would undeniably have taken much more time and discussion. A guidance document (CEN/TR15615, "Umbrella Document") has been produced on the application of the standards. Moreover, it is expected that, over time the standards will converge into a more unified set.

More information on this subject is given in the Information Papers on CEN standards to support the EPBD. These can be downloaded from the BUILD UP Portal.

Submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands)
Date: 29/04/2009

CEN/TR 15615 is not a standard, but a technical report and therefore the definitions (annex C) are not mandatory. However, most of the definitions are adopted also in the European standard EN 15603, which is one of the key standards in the set of standards to support the EPBD. It is intended that the annexes C and D of CEN/TR 15615 will form the basis of a future trilingual standard covering common definitions and symbols for energy calculations. Most Member States are planning to adopt the CEN standards in one way or another within a few years.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 29/04/2009

It may be that although the National Standard Body produced a national language version, the standard will always be available in English (the official text), in many cases also a French and German version may be available. The French language versions can be ordered from AFNOR and other CEN countries where French is the official language, the same for the German versions, they can be ordered from DIN, ON, etc..

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands)
Date: 29/04/2009

For instance: in EN ISO 13789 the subscripts for transmission and ventilation are T and V in ISO and tr and ve in CEN.
There may be two reasons:
1) because the EN ISO standard was already published before the common symbols were agreed upon in CEN (which was in 2007);
2) because the ISO standard is closely linked to other ISO standards which use different symbols.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 29/04/2009

In particular in the context of building regulations it is essential that a prescribed method is verifiable and legally secure and that there is consensus on the procedures. Therefore, transparency, robustness and reproducibility are important quality aspects which may hinder the choice of a detailed simulation tool. An overview of advantages and disadvantages of different types of methods, depending on the application, is given in the Buildings Platform Information Paper P026 which can be downloaded from the BUILD UP Portal.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 29/04/2009

It is a fact that in general most of the preparatory work in the Technical Committees and working groups in CEN is in English. The underlying documentation and the preliminary drafts are in English. When publishing a draft standard (prEN), it is up to DIN (German NSB) and AFNOR (French NSB) to decide if they want to translate and provide CEN with a German or French version. The time schedules allow for 2 months to make this translation available. It is up to the so called National Standards Bodies (NSBs) to decide if other national language versions will be produced. This decision will only be taken if this is required by the users. If the user group is a small expert group of, for example, software developers this seems unlikely.  When the standard is referred to in a more general way by a bigger target group, translation should be considered by the NSB.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 2008.03.10

Standards are copyright protected property of the publisher (CEN , ISO etc.) and not part of the public domain.
Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 2008/03/10

In general questions on standards could be answered by the National Standard Body helpdesk. They may also refer you to their national experts who have been involved in the preparation of the standard on a national or international level.
For the EPBD standards the BUILD UP website (www.buildup.eu) has a FAQ section and will offer a possibility to raise matters and participate in discussions. Your feed back (e.g. comments and suggestions) is also highly appreciated at the CENSE website (www.iee-cense.eu).

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 29/04/2009

General
The commission supported the development of the CEN standard by giving a mandate to CEN to produce the standards needed to support the implementation of the EPBD. It will be beneficial for Europe if all Member states use these standards as reference. However building regulation is an area where the EU Member States claim their national privilege to formulate the national legislation (also the EPBD adopted the subsidiarity principle in this respect). Although most MS say they use the CEN standards as a basis, as these procedures are in accordance with the EPBD, most of the Member states do not require the direct use of these standards. Standards are worked out in such a way that direct practical use, without supporting national information (national annexes), may be difficult. In some MS part of the content will be found in national publications or regulations, in some other MS using the EPBD standards is always an alternative solution.

Legal arguments
The EPBD has stimulated the more rapid development of CEN standards (ENs) for energy calculation procedures for buildings and their systems, and the related standards that are needed to specify buildings and systems performance in accordance with the Directive. The European Commission issued a mandate to CEN in order to speed up the development of standards needed for implementation of the EPBD.

In the case of the Construction Products Directive (CPD), the European Commission issues mandates to CEN to make use of CEN standards mandatory for all Member States.
In contrast with the CPD, the EPBD allows national and regional differentiation: the European Commission is responsible for generating a common framework (the Directive) in the field of energy efficiency in the building sector. The implementation of the framework and the definition of requirements and procedures is within the exclusive jurisdiction of each Member States (subsidiary principle). The Member States are not bound to use any standard in their regulations. The implemented procedures can be fully covered in the national laws without reference to national or European standards.

Practical arguments
From a practical point of view, within the given short timescale (2004-2007) it was impossible to produce a set of approved and published standards to be implemented in the Member States before the national implementation of the EPBD (which began in 2006).
Consequently, Member States, in the preparation of national legislation, had to refer to either existing or new national procedures.

In addition, at the time of writing the CEN standards, only a limited number of countries had practical experience with procedures for assessing the integrated energy performance of buildings that could be used in national building regulations. Several of the CEN standards reflect this situation by allowing different options to be decided at national level.
Nevertheless, most Member States are planning to adopt the CEN standards in one way or another within a few years.

The IEE CENSE project (www.iee-cense.eu) organizes the information on the CEN standards and the feed back from the Member States.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 29/04/2009

We expect a further harmonization in the near future. In particular when feedback from the Member States and other target groups has lead to recommendations for improvement of the CEN standards and when these recommendations have been implemented in updated versions of the standards in a few years from now.
The IEE CENSE project (www.iee-cense.eu) may play an important role in identifying and removing the barriers and to promote examples of good practice.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 29/04/2009

Today most companies (consultants, manufacturers and contractors) work internationally. From their point of view it is preferable to have internationally accepted calculation methods and input data for the energy efficiency of buildings and building systems.
European standards should therefore form the basis of any revision of national building codes. The IEE CENSE project (www.iee-cense.eu) will interact with all partners (building code writers, consultants, manufacturers, educational institutions, etc.).
The point is to establish a two-way communication:
- CENSE will provide information about the “European Method” and explain the background and use of the standards.
- CENSE will gather information on any obstacles that are encountered and provide examples of good practice for use when applying the standards, in dialogue with the Member States and other stakeholders and will provide feedback to CEN for a any revision of the standards.

So will the future be one harmonized set of CEN procedures to assess and express the energy performance of buildings?

That would be ideal from the point of view of harmonization.
However, we still have to see to what extent regional differences in Europe require differentiation of input data and boundary conditions.

This has to do with differing climates, building traditions (types of new and existing buildings, types of skill) and the economic and social climate (user behaviour, availability of products and skills), legal settings and quality assurance. It may also have to do with related national or regional requirements.To name a few:

•  indoor air quality (e.g. which affects the input data for ventilation rates),
• summertime comfort (e.g. which affects the input data for temperature set points), 
•  usability of indoor spaces (e.g. which affects the classification of an attic as a storage space or as a study or bedroom).

It will be very interesting and important to learn to what extent such differentiation will constitute an obstacle for trans-border transparency, in particular for the comparison between Member States of the energy performance of buildings.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 29/04/2009

To support the open EU market, more and more standards have been prepared as ENӳ. For building products this is even a requirement based on EU mandates to CEN according to the EU-CPD (Construction Product Directive). To stimulate an open EU market, construction products shall only be specified according to mandatory, socalled ԨarmonisedԠEN (or EN-ISO) standards.

The EPBD stimulates EN standards for the energy calculation procedures for buildings and their systems, and all related performance prescriptive standards needed to specify buildings and systems in relation to the Energy Performance of Buildings Directive. The European Commission gave a mandate to CEN in order to speed up the development of standards needed for the EPBD implementation.

CEN didnӴ start this work from scratch. Already existing CEN Technical Committees have been quite active during the last 15 years preparing international standards in this field. These TCӳ have been involved in developing the CEN program to support the implementation of the EPBD.

The process was overseen by CEN/BT WG 173, Energy performance of buildings project group (currently: CEN/BT TC 371). Itӳ task was to coordinate the work and to ensure that standards prepared in different committees interface with each other in a suitable way.

The EU Mandate to CEN:
The European Commission decided after consultation of the Member States experts, interest groups and CEN, that there was an urgent need for standards to support the EPBD. The aim was to offer within a short period (2004-2006) a clear and consistent set of standards as basis for the national procedures in the Member States. In particular the Member States with a very limited experience in the field of the EPBD could benefit from this.

On the long term, harmonisation of the standards will also be attractive for all Member States. The maintenance and further development costs will be lower compared with the situation where all NSBӳ have to do this on their own. In addition, there is great advantage in having harmonised standards throughout Europe. The widescale implementation of new technical solutions, equipment and systems will become easier if the performance is calculated in a similar way. This means that the industry may have a bigger market throughout Europe which may also benefit their opportunities on the world market.
The development of CEN standards may lead to CEN-ISO standards. The ISO standards are widely accepted and may even increase the market opportunities of the European industry.

Regional differences in climate, building tradition, legal settings, quality assurance and user behaviour in Europe will have impact on the input data and consequently on the energy performance. These differences will also lead to different choices when it comes to finding the optimum balance between accuracy and simplicity. The standards developed under the EPBD have to be flexible enough to accommodate these differences.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands)
Date: 29/04/2009

The developed standards reflect the requirements of the EPBD as given in the different articles and the annex. The procedures as given in the standards meet the essential requirements as set out by the EPBD.

Note that the EPBD is an example of the application of the principles of subsidiarity and proportionality: general principles are established at Community level, but the detailed implementation are left to Member States, thus allowing each Member State to choose the regime which corresponds best to its particular situation.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands)
Date: 29/04/2009

The set of CEN-EPBD standards consists of 43 titles or parts and can be grouped as follows:
The building physics standards, e.g. describing the calculation of heat transfer by transmission and ventilation, load and summer temperature, solar transmittance and the calculation of the energy need for heating and cooling of the building.
In the second group there are standards on the description and properties (classification) of ventilation systems plus cooling and air conditioning systems.
The third group is focussing on the description of space heating and domestic hot water systems:
- The generation efficiency.
- The emission efficiency.
- Domestic hot water systems.
- Low temperature heating and cooling systems integrated in building elements (embedded systems).
A series of supporting standards on:
- Lighting systems for buildings (including the effect of daylight)
- Controls and automation for building services
- Classification of the indoor environment
- Financial economic evaluation of sustainable energy applications.
A set of standards on inspection:
- Boilers and heating systems
- Cooling- and AC systems
- Ventilation systems.
And, last but not least, the two key standards on expressing energy performance and for energy certification of buildings, the overall energy use, primary energy and CO2 emissions, the assessment of energy use and definition of energy performance ratings.

If an ISO (International Organization for Standardization) standard is also an EN ISO standard, then it is a European standard just like any other EN (European) standard. As illustrated in several CENSE Information Papers, e.g. P92 or P94, a CEN standard to support the EPBD is one of a series of standards, which are mutually related and serve particular European (EPBD) needs; in particular: which are meant to be applied in the context of national building regulations. If, for this purpose, such an EN ISO standard needs to make a reference to another EN standard, then one may find in the standard a distinction between references to EN standards for use within the CEN area and references to ISO or national standards for use outside Europe.
In EN ISO 13790, for instance, this was solved by concentrating all references to other standards in one normative annex (Annex A), which provides for the "CEN area": references to CEN (EN or EN ISO) standards and for "elsewhere": references to ISO standards or, in absence of ISO standards, to national standards (see CENSE Info Paper P92 which can also be downloaded from the BUILD UP Portal).

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands) and Brian Anderson, BRE (UK)
Date: 19/02/2008

Yes, but some of the required input data may not be available at reasonable costs. For those cases default values may be provided at national level, e.g. as function of type and age of construction.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Brian Anderson, BRE (UK)
Date: 19/02/2009

Heat is lost from a building or building part by transmission or ventilation, as a result of a positive temperature difference between the indoor and outdoor (or other) environment. However, if the indoor temperature of the considered building or building part is lower than the temperature of the other environment (outdoor environment or another building part), the heat loss becomes negative. Therefore the more neutral term “heat transfer” was introduced from the 2007 versions of the EPBD related standards on. The downside of this is, that now it must be explicitly stated which direction has the positive sign. By definition, if the heat flows from the considered building or building part to the other environment, it has a positive sign.
NOTE: a negative heat loss should not be confused with “heat gain”. The term heat gain (see e.g. EN ISO 13790, energy use for heating and cooling) is used for solar and internal gains which are not a function of the indoor-outdoor temperature difference: if the indoor temperature rises, e.g. due to excess gains, the heat transfer by transmission and ventilation will automatically rise proportionally, but the solar and internal heat gains remain the same (compare the electric equivalent: a current through a resistor versus a current source).

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO (The Netherlands) and Brian Anderson, BRE (UK)
Date: 19/02/2009

Each method has its own applications: the seasonal method is the simplest, but it is applicable only in climates where seasons are clearly defined, the monthly method is easy to use in buildings without or with small intermittence effects, while the simple hourly method is of more general use, but requires hourly meteorological and use data and, despite the fact that it produces hourly results, it is based on a simplified model with only the monthly results validated. Concerning the pro's and con's of a detailed simulation method, see chapter 8 of CENSE Information Paper P92 which can also be downloaded from the BUILD UP Portal. The choice is strongly related to the (national) application and may depend on the type and complexity of the building.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 29/04/2009

The monthly method and the simple hourly method were indeed validated by comparison to detailed calculations and to the actual energy use of several buildings (monthly values). The monthly method for heating has been in use since 1990. (See annex H of the standard EN ISO 13790.)

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 21/10/2009

This is explained in detail in annex I.5 of the standard EN ISO 13790. The main difference is that the degree day method contains an implicit assumption about the effect of internal and solar gains on the heat balance (independent of the specific building), while this effect is explicitly taken into account in the monthly method (as a function of the building parameters).

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 21/10/2009

Background information on the origin and rationale of the monthly method can be found in Annex I of the standard EN ISO 13790. It also contains more technical information concerning the content of EN ISO 13790, as well as Annex H of the standard EN ISO 13790 and the bibliography at the conclusion of the standard.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk (TNO, The Netherlands)
Date: 21/10/2008

This is possible if not only the overall energy performance (in MJ or kWh), but also the system energy performance is reported separately. The same goes for the local production of renewable energy. EN 15603 describes how this could be done. Given the different lifespan of building elements and building systems separate consideration would be beneficial.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 10/03/2008

There is a consensus within Europe that the built environment has a major task to reduce the CO2 emissions and convert to sustainable energy systems. The energy saving targets are high and there is a need to show in a non controversial way the achievement of the various Member States. This is one of the reasons that harmonised calculation procedures, including harmonised input parameters, are desirable. However there are still a lot of national differences in the various regulations directly influencing the EP requirement level; for example the requirements on ventilation or other health related issues. The EN 15251 “Indoor Environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality thermal environment, lighting and acoustics “ has been developed to give the MS regulators the opportunity to harmonise these requirements.
See also question "What are the future prospects for the status of the CEN standards?" and other related questions.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 10/03/2008

This is up to the National Standard Body, most countries offer both possibilities.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 2008/03/10

The energy performance of products is taken into account in an indirect way. The EPBD CEN standards are generally dealing with performance description of buildings and systems. The EPBD standards describe the way the system performance has to be determined. These values are influenced by the relevant product specifications. The standards developed under the EPBD either refer to relevant product standards or specify the required input for the system standards.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Dick van Dijk, TNO and Jaap Hogeling, ISSO (The Netherlands)
Date: 10/03/2008

EN ISO 13790 describes calculation methods for the energy need for heating and cooling for each building zone, whereas EN 15603 deals with the overall energy use and the energy performance of buildings, collating the results from other standards, including those from EN ISO 13790.
More information: CENSE Information Paper P095 which can also be downloaded from the BUILD UP Portal.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Anna Staudt and Hans Erhorn, Fraunhofer Institute of Building Physics (Germany)
Date: 2008/02/04

The primary advantage of the more detailed and thus more advanced method (holistic approach) is the higher quality and reliability of the results, due to the very realistic model on which the calculation is based. The intermediate results are quite exact and very appropriate for further more detailed analysis. Its main disadvantages are the need for suitable computer software for the complex calculation and the longer time required to perform the calculation.
The advantages mentioned above represent the disadvantages of the simplified approach, which uses a very approximate model. Nevertheless, the results can definitely be used to assess and compare the energy performance of simple buildings with conventional performance. The advantages of the simplified approach are the shorter time required to perform the calculation, and the fact that it can be done by hand.
More information: CENSE Information Paper P095 which can also be downloaded from the BUILD UP Portal.

Question submitted by: Dick van Dijk (TNO, The Netherlands)
Anwered by: Anna Staudt and Hans Erhorn, Fraunhofer Institute of Building Physics (Germany)
Date: 2008/02/04

 The EPBD states in Article 4 that a Member State has to take the necessary measures to ensure that minimum energy performance requirements for buildings are set. It does not state that the requirements have to be set nationally. Even the methodology that is the basis for the requirements (see Article 3) may be set at national or at regional level.

Authors: Hans ERHORN and Heike ERHORN-KLUTTIG (FHG)
Date:   24/03/06

No. If the existing requirements already meet the definitions of Articles 4-6, a Member State does not necessarily have to make them more demanding. Article 4 states that the requirements shall be reviewed at regular intervals (not longer than 5 years) and if necessary be updated in order to reflect technical progress in the building sector.

Authors: Hans ERHORN and Heike ERHORN-KLUTTIG (FHG)
Date:   24/03/06

Buildings with a useful floor area over 1000 m² which undergo a major renovation have to meet minimum energy performance requirements (in so far as this is technically, functionally and economically feasible).  The minimum energy performance requirements may be set in two different ways:

1. for the renovated building as a whole
2. for the renovated systems or components
The objective is the improvement of the overall energy performance of the building.
Note that Germany, for example, also sets minimum requirements for buildings that have a useful floor area less than 1000 mý.

Authors: Hans ERHORN and Heike ERHORN-KLUTTIG (FHG)
date:   24/03/06

Article 4 requires that minimum requirements are based on the methodology referred to in Article 3 (calculation of the energy performance of buildings). For more information on the general framework for the calculation of energy performance of buildings see the Annex of the EPBD. The energy performance of a building shall be expressed in a transparent manner and may include a CO₂ emission indicator.

If the building has a useful floor area of more than 1000 m², alternative systems have to be considered and taken into account (see Article 5).

Authors: Hans ERHORN and Heike ERHORN-KLUTTIG (FHG)
Date:   24/03/06

No. The EPBD requires Member States to take the necessary measures to ensure that energy performance requirements for buildings are set (see Article 4). The requirements may differentiate between new and existing buildings and different categories of buildings. The EPBD also includes a list of buildings for which requirements are not obligatory. Article 5 of the EPBD states that Member States have to take necessary measures to ensure that, for new buildings with a useful floor area of more than 1000 m², certain alternative systems (e.g. renewable technologies) have to be considered and taken into account. Article 6 requires that existing buildings undergoing a major retrofit have to meet minimum requirements in so far as this is technically, functionally and economically feasible. In either case individual Member States provide the quantitative definition of the minimum requirement.

Authors: Hans ERHORN and Heike ERHORN-KLUTTIG (FHG)
Date:   24/03/06

Demonstration of the technical feasibility and the user-friendliness of building concepts that go (far) beyond the national EP requirements and that may include innovative technologies and strategies is very important to set the path for enforced EP requirements. In the past, but also currently, a lot of EU Member States are supporting those demonstration project. The building concepts demonstrated cover both, new buildings and building renovation projects. The energy performance levels can be as ambitious as so-called “zero energy houses”, but also more contemporary like 20% to 50 % lower than the current national requirements. In many cases the idea is to show that these low energy consumptions can be achieved with only few additional costs and that these costs are going to be paid-back within a limited amount of years. As buildings are valuable objects, building owners tend not to rely on studies and simulations of the effects of energy concepts only, they prefer to have a realised and in detailed measured, analysed and proven building before they overtake a new building concept. This makes demonstration projects even more relevant. A well-known international, EU-supported demonstration programme is the Ecobuildings programme. The aim of the building concepts is “towards an energy efficient European building stock beyond national requirements”. Currently 4 projects that have been started in the 6th Framework Programme are in the final phase and many project results are already available for the public. An Information Paper on Ecobuildings will be soon presented on the EPBD Buildings Platform. For more information go to: http://www.ecobuildings.info

Authors: Hans ERHORN and Heike ERHORN-KLUTTIG, Fraunhofer Institute of Building Physics Date: 19/11/07

Many countries have started studies on comparing their own EP requirements with those of neighbour countries. They are currently in different stages of realisation and not all of them are going to be published. A new IEE SAVE project “ASIEPI – Assessment and Improvement of the EPBD Impact (for new buildings and building renovation) will also deal with this item. The project is running from October 2007 to March 2010. The results of the work will be published as Information Papers on the EPBD Building Platform. The first Information Paper on the intercomparison study is foreseen for March 2008.

Authors: Hans ERHORN and Heike ERHORN-KLUTTIG, Fraunhofer Institute of Building Physics
Date:   19/11/07

 The status of EPBD implementation in nearly all EU Member States countries is available on the EPBD Building Platform in the form of special Information Papers, so-called Country Reports. The following list gives an overview on the Papers that are available in the Northern and Middle European Member States and which status they document:

- Austria: P036 ; status: March 2007

- Belgium – Flemish Region: P006 ; status: August 2006

- Belgium – Brussels Capital: P020 ; status: August 2006

- Denmark: P009 ; status: August 2006

- Finland: P044 ; status: May 2007

- England and Wales, Scotland and Northern Ireland: P050 ; status: September 2007

- Germany: P021 ; status: October 2006

- Ireland: P011 ; status: August 2006

- Luxembourg: P037 ; status: March 2007

- the Netherlands: P007 ; status: August 2006 and P038 ; status: February 2007

- Norway: P022 ; status: August 2006

- Sweden: P023 ; status: August 2006 and P047 ; status: May 2007

Authors: Hans ERHORN and Heike ERHORN-KLUTTIG, Fraunhofer Institute of Building Physics
Date:   19/11/07

Key aspects of the Certificates include (see also article 7 of the EPBD):

• They shall be available when buildings are constructed, sold or rented out - so they are applicable to existing buildings as well as new ones.
• They should be accompanied by recommendations for cost-effective improvement of the energy performance including reference values such as benchmarks
• For public buildings the Certificate has to be publicly displayed (note: the definition of "public buildings" is unclear and implementation may differ between Member States)
• Certificates cannot have a validity of more than 10 years, and some Member States may apply shorter periods.

Author:  Roger HITCHIN (BRE)
Date:   07/04/06

 A number of European Standards are being developed in parallel with the implementation of the Directive(see also Information Paper P02). Unless national legislation demands it, they are not mandatory. However, when agreed, they should represent good practice. Many countries are taking note of the draft standards in their implementation. Some standards are likely to be further developed as experience in implementing the Directive is gained. Over time it is probable that the range of national implementation mechanisms will tend to become less diverse and will instead reflect the developed European Standards.

The draft standards are due to be issued for formal voting during 2006. If accepted, they will become full CEN standards in 2007.

Author:  Roger HITCHIN (BRE)
Date:   07/04/06

Member States have discretion in how they implement the Directive as long as they satisfy its requirements. Depending on their legal and building control systems together with their existing infrastructure and practices, different countries will implement it in different ways. Over time, some procedures may become more widespread than others.

Author:  Roger HITCHIN (BRE)
Date:   07/04/06

An "Asset" Rating is:

• a calculated rating based on standard weather and building use
• similar in principle to "typical use" consumption figures for cars
• useful when comparing two buildings with different users, i.e. provides like-for-like figures

An "Operational" Rating is:

• based on measured energy use
• takes how the building is used and managed
• useful for energy managers and potential users of the building because it includes factors they control.

NB. the relevant CEN standards have adopted the terms "Calculated Rating" and "Measured Rating".  These are equivalent to "Asset Ratings" and "Operational Ratings" respectively.

Author:  Roger HITCHIN (BRE)
Date:   07/04/06

They serve two purposes:

1. Purchasers and renters of buildings will be able to compare the energy performance of different buildings before signing. While Energy Performance Regulations require minimum standards, performance ratings will identify buildings that go beyond this to achieve higher specification.
2. Building and energy managers will be able to compare their building's energy performance with other buildings and identify possible improvements (these could include better operational practices or modifications to the fabric or services)

Author:  Roger HITCHIN (BRE)
Date:   07/04/06

Key aspects of the Certificates include (see also article 7 of the EPBD):

• They shall be available when buildings are constructed, sold or rented out - so they are applicable to existing buildings as well as new ones.
• They should be accompanied by recommendations for cost-effective improvement of the energy performance including reference values such as benchmarks
• For public buildings the Certificate has to be publicly displayed (note: the definition of "public buildings" is unclear and implementation may differ between Member States)
• Certificates cannot have a validity of more than 10 years, and some Member States may apply shorter periods.

Author:  Roger HITCHIN (BRE)
Date:   07/04/06

This Directive lays down requirements as regards (see article 1 of EPBD):

 (a)   the general framework for calculation methodology the integrated energy performance of buildings, i.e. there must be in each Member State one or more calculation methods for determining the integrated energy performance of buildings;

 (b)   the application of minimum requirements for the energy performance of new buildings;

 (c)   the application of minimum requirements for the energy performance of large existing buildings that are subject to major renovation;

 (d)   the energy certification of buildings; and

 (e)   the regular inspection of boilers and of air-conditioning systems in buildings and in addition an assessment of the heating installations in which the boilers are more than 15 years old.

Author:  Roger HITCHIN (BRE)
Date:   07/04/06

According to the European Climate Change Programme, the Directive could deliver a reduction of up to 45 million tonnes of carbon dioxide by 2010. In order to meet the agreed Kyoto targets, the European Union must implement reductions of 330 million tonnes between 1990 and 2010.

Author:  Roger HITCHIN (BRE)
Date:   07/04/06

The 160 million buildings in the EU use over 40% of Europe's energy and create over 40% of its carbon dioxide emissions, and this proportion is increasing. Under the Kyoto protocol, Europe is committed to reducing emissions and the Directive is intended to contribute to this. The cost effective savings potential is around 22% of present consumption in buildings that can be realised by 2010.

Author:  Roger HITCHIN (BRE)
Date:   07/04/06

Details and full Information on infringement procedures can be found here: ec.europa.eu/dgs/energy_transport/infringements/index_en.htm

For specific information regarding infringement procedures in relation to the EPBD (2002/0091), please visit eur-lex.europa.eu/smartapi/cgi/sga_doc

Author: Sabrina PRIEUS (BBRI)
Date: 14/05/08

Information on the recasting technique by the European Commission is available here: http://ec.europa.eu/governance/better_regulation/codif_recast_en.htm

For information on the main problems, main policy objectives, and policy options, the List of Strategic and Priority Initiatives can be accessed here: clwp2008_roadmap.pdf

You may also find of interest the details and information from the conference and discussion on the recasting of the EPBD which is available at: http://www.buildup.eu

Author: Sabrina PRIEUS (BBRI)
Date: 14/05/08

Article 4 of the EPBD stipulates explicitly that attention should be paid to indoor climate conditions: “Member States shall take the necessary measures to ensure that minimum energy performance requirements for buildings are set … These requirements shall take account of general indoor climate conditions, in order to avoid possible negative effects…”.

This is also listed in the annex of the EPBD: “The methodology of calculation of energy performances of buildings shall include…

(d) ventilation;…

(h) natural ventilation;…

(i) indoor climatic conditions, including the designed indoor climate.”

Whereas in the past the major challenge was to keep our buildings sufficiently warm, nowadays the challenge is in guaranteeing reasonable comfort conditions in summer without (or with minimum) cooling energy. It is therefore important that building designers and other stakeholders understand the thermal behavior of a building and its occupants and are aware of the available alternative techniques that substantially improve the comfort in the building and significantly decrease (or even eliminate) energy consumption. For example, solar and thermal control techniques, heat amortisation and heat dissipation techniques have been proven to be extremely efficient and may decrease the cooling load of buildings up to 80 %.

Based on the idea that the human body continually adapts to a variety of conditions, an adaptive standard, would not include fixed indoor parameters but, would aim to promote (easy) adaptation by using the following principles:

·         People adapt more easily to the temperatures they are most familiar with. The range of conventional temperatures is population related and depends on geography, culture (customs) and climate. Therefore, the adaptive standard would define a range of conventional temperatures for each specific population and building type at different seasons of the year.

·         Adaptation is easier under more or less stable conditions. An adaptive standard would indicate which degree of stability of indoor conditions is required and how to achieve this.

·         A building may or may not provide opportunities for user friendly adaptation and control over the thermal environment. The adaptive standard would prescribe which opportunities for control are required (f.e. openable windows, temperature or solar controls, etc.) 

The adaptive approach is beginning to influence standards and guidelines for comfort in buildings, as is evident from the use of field results in ASHRAE Standard 55-2004 (ASHRAE, 2004) and (in the UK) the CIBSE (Chartered Institute of Building Services Engineers) Guide (CIBSE, 2006).

Adaptive comfort builds on the principle that people experience differently and adapt, up to a certain extent, to a variety of indoor conditions, depending on their clothing, their activity and general physical condition. Therefore, contrary to the conventional cooling which is based on pre-calculated temperatures and humidity levels, the adaptive approach is based on a non fixed set of conditions, taking into account thermal perception and behavior of the user, requiring him to take an active role in controlling his indoor environment.

The main international guidelines and standards on thermal comfort are:

·         International Standard ISO 7730. This standard is based on Fanger’s Predicted Mean Vote (PMV), which predicts the mean thermal sensation of a group of people, and the Predicted Percentage of people Dissatisfied with the environment (PPD).

·         ASHRAE 55 defines conditions that are being considered satisfactory for a specific percentage of users, including calculation methodologies for thermal comfort based on PMV/PPD

·         CEN 15251: Criteria for the indoor environment including thermal, indoor air quality, light and noise. The CEN standard defines minimum ventilation requirements, minimum and maximum indoor temperatures that can be used for energy calculation, assessment and certification. It is different than prescribed standards because it makes a difference between mechanically ventilated systems and naturally ventilated systems. For buildings without mechanical ventilation /cooling, alternative methods are proposed.

These guidelines and standards specify comfort in a broader sense that is easier to refer to and often stem from numerous more detailed and sophisticated guidelines and standards (normative references) such as:

·         ISO 7243, Hot Environments – Estimation of the heat stress on working man, based on the WBGT Index (wet bulb globe temperature)

·         ISO 7726, Ergonomics of the thermal environment — Instruments for measuring physical quantities

·         ISO 7933, Ergonomics of the thermal environment — Analytical determination and interpretation of heat stress using calculation of the predicted heat strain

·         ISO 8996, Ergonomics of the thermal environment — Determination of metabolic rate

·         ISO 9920, Ergonomics of the thermal environment — Estimation of the thermal insulation and evaporative resistance of a clothing ensemble

·         ISO 10551, Ergonomics of the thermal environment — Assessment of the influence of the thermal environment using subjective judgement scales

·         ISO 11399, Ergonomics of the thermal environment — Principles and application of relevant International Standards

·         ISO TR 11079, Ergonomics of the thermal environment — Analytical determination and interpretation of cold stress using calculation of the required clothing insulation (IREQ) and the assessment of local cooling effects

·         ISO 13731, Ergonomics of the thermal environment — Vocabulary and symbols

·         ISO/TS 13732-2, Ergonomics of the thermal environment — Methods for the assessment of human responses to contact with surfaces — Part 2: Human contact with surfaces at moderate temperature

·         ISO/TS 14415:, Ergonomics of the thermal environment — Application of International Standards to people with special requirements

·         Humphreys, M.A. and Nicol, J.F. (1998) Understanding the Adaptive Approach to Thermal Comfort, ASHRAE Transactions 104 (1) pp 991-1004

·         DeDear (2004), Thermal Comfort in Practice. Indoor Air Journal. Vol 14. Supplement 7, pp 32-39.

·         McCartney K.J and Nicol J.F. (2002) Developing an Adaptive Control Algorithm for Europe: Results of the SCATs Project. Energy and Buildings 34(6) pp 623-635

The general tendency on summer comfort should be to use the best available practical means, including alternative techniques, to control the indoor environment and provide stable indoor conditions in order to avoid discomfort, using the least possible energy. 

In line with the principle of equivalence, each Member State implements various EN standards into its regulations to assist in the evaluation of the performance of alternative cooling techniques. Examples of such standards are:

·         EN 13790: Energy performance of buildings-Calculation of energy use for space heating and cooling

·         EN 15241: Calculation methods for energy losses due to ventilation and infiltration in commercial buildings

·         EN 15242: Calculation methods for the determination of air flow rates in buildings including infiltration

As has already been done for centuries before us, good indoor climate conditions during summer can be achieved through efficient use of the physical and natural conditions and sources around the building such as its position and orientation, the relief, the climate, the vegetation, the wind direction, air velocity etc. During design of the building such parameters need to be taken into account to prevent the building from overheating, by using proper materials, making efficient use of windows and openings, providing sufficient shading, night cooling, etc. Occupants should also be provided with control over their environment like for example openable windows and manual override on control systems to ensure satisfaction and increased adaptation levels during hot spills.  

This is defined in EN 13829, § 6.1.2. All exterior surfaces, plus floors, ceiling and walls to neighbouring apartments are taken into account.
However, other assumptions are used in some countries to extract indicators that better fit the national requirements of the EP-regulations (see question regarding the measurement of multi-family buildings).

Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)
Date: 2008/12/12

Measurements usually show that light (e.g., timber-frame or steel) constructions are leakier than massive construction, but this is not bound to be. In fact, PassivHaus houses are often light constructions and are very airtight.

The general statement that can be drawn is that light constructions are more sensitive as the airtight layer can be more affected by poor design and workmanship than in massive constructions.

Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)
Date: 2008/12/12

To our knowledge, the UK is the only country that has made testing mandatory. This has been in force since 2002 for large buildings and extended to most buildings in 2006.

Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)
Date: 2008/12/12

The airtightness measurement of single apartments is usually performed the same way as in individual houses. Therefore, there is no specific protocol to balance the pressure between the apartment under test and other apartments. Different protocols may lead to very different results.

Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)
Date: 2008/12/12

There is little information on the subject at the moment. A study referenced in a paper written by Erhorn et al. and presented at the 2008 AIVC conference shows airtightness values of 31 “PassivHaus” houses at commissioning and 2 year later. The average n50 at commissioning and 2 year later were 0.37 and 0.46 ach at 50 Pa, respectively.

Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)
Date: 2008/12/12

Measuring or evaluating the airtightness of multi-family buildings is challenging as there may be technical and practical difficulties that prevent from pressurizing the whole building. These difficulties include for instance building configuration (e.g., exterior hall ways that do not allow pressurisation from a single point), pressurisation fan size, stack effect, or cost.
Therefore, the measurement of the whole envelope of multi-family buildings is rarely performed in practice. However, several countries use alternate schemes to overcome these problems, for instance:
- in France, in the framework of the BBC-Effinergie label, the measurement can be performed by apartment. The basic idea is to test a sample (e.g., of 3 units for a building of 30 apartments or less) and to make a weighted average of the results to estimate the global airtightness.
- in Norway, tests on single apartments can be used. It is seen as a simple practical measure that also encourages airtightness between apartments, which is good to avoid noise and cross-contamination.

Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)
Date: 2008/12/12

There exists a certification scheme in Germany which is not compulsory to perform tests.
There exists a compulsory authorisation process in France for technicians who perform test on BBC-Effinergie buildings.
To our knowledge, there is no other certification or authorisation scheme in European countries.

Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)
Date: 2008/12/12

There is no up-to-date document at this time.

Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)
Date: 2008/12/12

To our knowledge, only two low-energy labels include a minimum requirement for low-energy buildings:
- the PassivHaus standard (www.passivhaus.de) that requires an airtightness better than 0.6 air changes per hour at 50 Pa (n50 <= 0.6 ach);
- the BBC-Effinergie standard (www.effinergie.org) that requires for an individual house an airtightness better than 0.6 m3/h per m2 of cold surface area at 4 Pa (this translates for an individual house to a n50 of about 2.5 ach).
Although a minimum requirement is not imposed, the global energy use requirements of low-energy labels encourage to achieve good envelope airtightness. Problems may arise when an appropriately set default value can be used, allowing buildings to be labelled although their airtightness is much worse than the default value.

Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)
Date: 2008/12/12

Now in Europe, many countries have adopted the n50 value (i.e., the leakage flow divided by the volume) for their EP regulation while others (e.g., Belgium, France, UK) use the envelope area normalisation. The rationale behind this latter choice lies in the fact that the volume is not needed for an energy performance calculation. Using the n50-value should require a precise definition of the way the volume is calculated, which to our knowledge, is not the case in any European country. On the other hand, the envelope area is usually well-defined in regulations.
More generally, the indicator used may be different depending on the application. The volume normalisation seems well-appropriate to pollutant transfer applications as the volume is a necessary input. Similarly, the exterior envelope area indicator seems well-appropriate to energy use applications. The floor-area normalisation may be interesting for comparison purposes as it is often more difficult to have access to the volume or envelope area data than the floor-area.

Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)
Date: 2008/12/12

To some extent yes. A collection and analysis of some data collected through the ASIEPI partners has been presented at the 2008 BlowerDoor conference (Papaglastra et al., 2008). However, caution should be exercised when comparing airtightness values :
- the measurement methods are not necessarily the same. EN 13829 mentions two methods (A and B) that can lead to very different results e.g., depending on how combustion appliances are sealed; (*)
- the calculation of the volume or the envelope area that is used to normalise the leakage flow may be different for the same building, depending on the assumptions adopted nationally or even by the operator.
It would be useful to harmonise these methods to be able to reliably compare and monitor results.

(*) In Belgium, additional specifications for the measurement of envelope airtightness have been published (http://www.epbd.be/go/airtightness-measurement)

Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)
Date: 2008/12/12

There are three major ways to estimate this impact:
- the simplest is to evaluate the infiltration losses based on a rule of thumb established by Drubul in 1988 (*) and suggested by Kronvall (**) in 1978. The rule says that the infiltration airflow rate in air changes per hour may be determined by dividing the n50 value by an empirical coefficient that lies between 10 and 30. In practice, the empirical coefficient is often set to 20 (i.e., the infiltration airflow rate is equal to the airtightness at 50 Pa divided by 20);
- an intermediate approach is to estimate the infiltration airflow rate based on the empirical model proposed in ISO 13790, annex G;
- a more detailed approach is to perform and hourly simulation of the airflow rates, based on a pressure network code such as that described in EN 13465.
Once the infiltration airflow rate is known, the calculation of the energy losses is straightforward.
In national regulations, one of those three methods is commonly used in the EP-calculation.

(*) Drubul C, Inhabitant’s behaviour with respect to ventilation, Technical note 23, Air Infiltration and Ventilation Center, 1988
(**) Kronvall J, Testing of houses for air-leakage using a pressure method, ASHRAE trans. Vol 84 no 1 1978

Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)
Date: 2008/12/12

Energy wastage due to envelope leakage has been estimated in various countries through numerical simulations:
- in Belgium and in Germany, the energy impact has been calculated to be about 10% of the energy performance level for individual houses;
- estimates based on simulations on 9 real buildings in France lie between 0.5 and 15 kWh-pe/m2 per year (depending on climate, ventilation system type, and building configuration), with an average of 6.6 kWh-pe/m2, between “default” and excellent airtightness

For comparison purposes, in Belgium, France and Germany, the impact of good envelope airtightness is similar to that of solar collectors for domestic hot water.

Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)
Date: 2008/12/12

The SAVE-DUCT project has shown that there are large discrepancies between countries on this subject (the project report is available through AIVC at www.aivc.org). Analyses performed on measurements results have shown that Belgian and French ductwork systems were typically 3 times leakier than Class A whereas Swedish systems commonly complied with Class B (i.e., 3 times tighter than Class A). The main reason is that the Swedish quality system (Boverket) imposes a rather pragmatic testing scheme which has encouraged the systematic use of ductwork with pre-fitted seals that guarantee good airtightness. This type of ductwork is very much used in Nordic countries where similar conclusions can be drawn.
This topic will be discussed in more detail during the next ASIEPI WP 5 Web Event in October 2009.

Anwered by: Rémi Carrié and Gaëlle Guyot (CETE de Lyon)
Date: 2008/12/12