ISO 16343:2013

INTERNATIONAL ISO
STANDARD 16343
First edition
2013-07-15
Energy performance of buildings —
Methods for expressing energy
performance and for energy
certification of buildings
Performance énergétique des bâtiments — Méthodes d’expression de la
performance énergétique et de certification énergétique des bâtiments
Reference number
©
ISO 2013
© ISO 2013
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ii © ISO 2013 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Symbols and abbreviations . 2
4.1 Introduction . 2
4.2 Principal symbols . 2
4.3 Subscripts . 2
5 Procedure for building energy certification . 3
5.1 General . 3
5.2 Content of procedure for building energy certification . 3
5.3 Content of the energy performance certificate . 5
5.4 Overall energy performance rating types . 5
5.5 Performance scale . 7
5.6 Recommendations . 8
6 Energy performance indicators . 8
6.1 Overall indicator . 8
6.2 Other indicators . 8
6.3 Indicator basis . 8
6.4 Normalization of energy rating . 8
7 Expression of energy requirements . 9
7.1 Ways of expressing the requirements . 9
7.2 Overall energy performance requirements .10
7.3 Modification of the impact of certain parameters .11
7.4 Renovation of and extensions to existing buildings .12
8 Reference values .13
8.1 Types of reference values .13
8.2 Content of reference values.13
8.3 Documentation of reference values .14
Annex A (normative) Parallel routes in normative references .15
Annex B (informative) Procedure for building energy certification documentation .16
Annex C (informative) Procedure for building energy performance classification .25
Annex D (informative) Energy certificate format .26
Annex E (informative) Requirements on the characteristics of the building envelope and
system components .29
Annex F (informative) Reference buildings or notional building approach .33
Bibliography .35
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
The committee responsible for this document is ISO/TC 163, Thermal performance and energy use in the
built environment, in collaboration with Technical Committee ISO/TC 205, Building environment design.
iv © ISO 2013 – All rights reserved

Common terms, deinitions, and symbols
Introduction
This International Standard is prepared by ISO/TC 163, Thermal performance and energy use in the built
environment, in collaboration with Technical Committee ISO/TC 205, Building environment design, and
is one of three closely linked documents dealing with definitions and general procedures for the overall
building energy performance rating and certification (see also Figure 1):
— ISO/TR 16344, Energy performance of buildings — Common terms, definitions and symbols for the
overall energy performance rating and certification;
— ISO 16343, Energy performance of buildings — Methods for expressing energy performance and for
energy certification of buildings;
— ISO 16346, Energy performance of buildings — Assessment of the overall energy performance.
ISO/TR 16344 provides a coherent set of terms, definitions, and symbols for concepts and physical
quantities related to the overall energy performance of buildings and its components, including
definitions of system boundaries, to be used in all International Standards elaborated within ISO on
energy performance of buildings.
ISO 16346 defines the general procedures to assess the energy performance of buildings, including
technical building systems, different types of ratings, and building boundaries.
Their development greatly benefited from similar CEN documents (viz. CEN/TR 15615, EN 15217, and
EN 15603) developed to support the European Energy Performance of Buildings Directive (EPBD).
A revision of the set of CEN standards to support the EPBD is anticipated in the near future. Issuing the
ISO documents aims to bring the key subjects of building energy performance assessment to the global
international level.
Given the strong demand for these standards at ISO level, it was decided not to delay the advancement of
these International Standards and Technical Reports by waiting on these CEN developments. However, it
is expected that a future revision of these International Standards and Technical Reports will be carried
out in collaboration with CEN under the Vienna Agreement.
Energy Performance (EP)
ISO/TR 16344
EP
Overall Energy
Performance of the
EP
ISO 16343
building including its
expressions
technical building
ISO 16346
systems
EP aggregation
Boundaries, classi
ication
Collect all energy elements
Building energy needs
and system energy losses
Component input data
Boundary conditions
Figure 1 — Flow diagram illustrating the successive elements of the general procedures
Introduction to methods for expressing energy performance and for energy certification of buildings
Expression of the energy performance of buildings is needed to
— enable the establishment of regulations regarding energy performance of buildings, and
— encourage building designers, owners, operators, and users to improve the energy performance
of buildings.
This International Standard provides methods to express the energy performance of buildings in a way
that serves these purposes. It is based on International Standards that provide methods to calculate or
measure energy performance.
This International Standard is intended to be used by
— developers of a procedure for building energy certification,
— building authorities setting minimum requirements on the energy performance, and
— building designers, building owners, building operators, and building users to assess the performance
of a planned or existing building and ways to improve it and to express this performance.
vi © ISO 2013 – All rights reserved

INTERNATIONAL STANDARD ISO 16343:2013(E)
Energy performance of buildings — Methods for
expressing energy performance and for energy
certification of buildings
1 Scope
This International Standard sets out ways of expressing the energy performance in an energy
performance certificate of a building (including the technical building systems) and ways of expressing
energy performance requirements. This includes an overall numerical energy performance indicator
and classes against benchmarks.
This International Standard additionally includes numerical indicators at system or component level.
This International Standard defines the different types of rating (such as calculated, measured, design,
and tailored rating) and the energy uses to take into account (such as heating, cooling, domestic hot
water, ventilation, and lighting).
This International Standard defines
a) overall indicators to express the energy performance of whole buildings, including heating,
ventilation, air conditioning, domestic hot water, and lighting systems (this includes different
possible indicators),
b) ways to express energy requirements for the design of new buildings or renovation of existing buildings,
c) procedures to define reference values, and
d) ways to design a procedure for building energy certification.
Furthermore, it provides a (calculation) link between delivered energy and the energy performance
indicators for buildings. Since a building generally uses more than one fuel (e.g. gas and electricity), the
different energy sources are collected per energyware. The overall rating is based on a weighted sum of
delivered energywares. The weightings can be related to, for instance, primary energy or CO emissions
to provide the end result of the calculation of energy performance.
It also provides calculation procedures to assess the energy performance on the basis of measured
energy use, including ways to convert the measured values to values under standardized conditions
(environment, user).
Finally, it defines the system boundaries needed to make a distinction between building energy needs,
technical building systems, energy supply systems on site, and distant energy supply systems.
This International Standard can be applied to a group of buildings if they are on the same lot, if they are
serviced by the same technical systems, and if no more than one of them has a conditioned area of more
than 1 000 m .
This International Standard provides different options at different levels. When this International
Standard is used to set up national or regional methods for expressing energy performance and/or for
energy certification of buildings, the choices between the options shall not be made by the individual
user but by authorized national or regional bodies.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 7345, Thermal insulation — Physical quantities and definitions
ISO 16346, Energy performance of buildings — Assessment of the overall energy performance
ISO/TR 16344, Energy performance of buildings — Common terms, definitions and symbols for the overall
energy performance rating and certification
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7345 and ISO/TR 16344 apply.
NOTE These terms and definitions are applicable to energy calculations according to this International
Standard, and to International Standards that are based on this one, to provide input to or use output from this
International Standard.
4 Symbols and abbreviations
4.1 Introduction
The International Standards dealing with energy performance of buildings introduce a large number of
quantities and their associated symbols.
To facilitate the use of the standards, a common set of symbols and subscripts have been defined, as
given in ISO/TR 16344. The symbols follow established standards on nomenclature such as ISO 7345
and introduce others that are common to the set of International Standards needed to assess the energy
performance of buildings, in particular, a set of subscripts to distinguish between different energy uses,
different energy carriers, etc.
The symbols given in ISO/TR 16344 concern only data passed from one standard (or standard part) to
another.
4.2 Principal symbols
Table 1 provides the specific symbols for this International Standard that are not covered in ISO/TR 16344.
Table 1 — Specific symbols and units for this International Standard
Symbol Quantity Unit
A conditioned area m
C
A thermal envelope area m
E
*)
R Reference
4.3 Subscripts
Table 2 provides the specific subscripts for this International Standard that are not covered in
ISO/TR 16344.
2 © ISO 2013 – All rights reserved

Table 2 — Specific subscripts for this International Standard
R requirement of regulation
C conditioned
S building stock
E envelope
5 Procedure for building energy certification
5.1 General
Clause 5 includes the following:
a) content of the procedure for building energy certification;
b) content of an energy certificate;
c) options in selecting the overall energy performance indicator EP which is used for the procedure for
building energy certification;
d) description of a performance scale;
e) description of types of recommendations to be included in the energy certificate.
In addition to Clause 5, Annexes C and D provide a way to describe a procedure for building energy
certification, an informative procedure for buildings classification, and three examples of an energy
certificate format.
5.2 Content of procedure for building energy certification
When the procedure for building energy certification is set up according to this International Standard,
information on the choices done shall be documented according to the format provided in Annex B.
The national party or other responsible body setting up a procedure for building energy certification
may state that its procedures are in accordance to this International Standard if the documentation
according to Annex B has been completed and the completed Annex B is published as national or
equivalent annex to this International Standard.
NOTE The purpose of the national annex is to achieve transparency on the differences in (national or regional)
procedures for building energy certification.
The following shall be included in a procedure for building energy certification.
a) BUILDING FUNCTIONS: Description of the function or functions of the building or part of the
building to which the procedure applies. The main functions of buildings considered are: single
family houses, apartment blocks, offices, education buildings, hospitals, hotels and restaurants,
sport facilities, wholesale and retail trade service buildings, and other types.
b) APPLICATION: Specification of the cases where the procedure for building energy certification applies:
— for sale, rent, new building design or after construction, display in a public building, etc;
— for checking compliance with minimum energy performance requirements or not.
c) TYPE OF RATING: Specification of the type of rating or ratings used, as specified in 5.4, for each
application [calculated (design, standard, or tailored) and/or measured; compliance check or not]
and for which building function(s) it applies. In case of design rating, this includes under what
conditions the design rating can be considered as or converted to a calculated energy rating for the
actually realized building. In case of measured energy rating, this includes specification of which
information on the actual conditions in the building is to be recorded (if any) and whether or not
corrections shall be made to correct for deviating periods, weather, and/or indoor conditions.
d) OVERALL NUMERICAL INDICATOR: Specification of what the overall numerical indicator represents,
as specified in 6.1, and specifically, which energy services are included and if renewable energy
produced on site is part of delivered energy or not.
e) NORMALIZATION: Specification of how the overall numerical indicator is normalized, as
specified in 6.4.
f) ENERGY PERFORMANCE REQUIREMENTS: Specification of how the energy performance
requirements are expressed, as specified in 7.1, including the way requirements for buildings with
different functions are defined, as specified in 7.2, the way the impact of certain parameters is
modified, as specified in 7.3, the way the requirements are expressed in case of renovations of and
extensions to existing buildings, as specified in 7.4, and the specifications in case of the application
of the notional (reference) building approach as described in Annex F.
g) REFERENCE VALUES: Specification of the definition of the reference values and the procedure to
define the values, as specified in Clause 8, including the way the impact of certain parameters is
modified, as specified in 8.1.
h) OTHER (COMPONENT) INFORMATION: Specification of other information on the energy performance
of main building and system components required on the certificate (if any).
i) ADDITIONAL INDICATORS: Specifications and assessment procedures on additional indicators
required on the certificate (if any, see 6.1).
j) RECOMMENDATIONS: Procedures to assess the recommendations for cost-effective improvements,
as defined in 5.6, and for which applications these are required on the certificate.
k) ENERGY PERFORMANCE CLASSES OR SCALING: Setup and procedures to assess the energy
performance class presented on a scale or other scaling (to be specified), as defined in 5.5.
EXAMPLES Examples of energy certificate classes or other scaling options are given in Annex D.
l) ADDITIONAL CONTENT: Specific additional content on the certificate to identify the characteristics
of the building.
EXAMPLES Conditioned area, number of conditioned floors, year or period of construction, and year or
period of the last major refurbishment.
m) ADDITIONAL INFORMATION: Specification of any other additional information required on the
certificate (if any).
n) COMPLETION OF THE CERTIFICATE: General procedures for the completion of the administrative
and technical data required on the certificate, as specified in 5.3.
o) FORMAT OF THE CERTIFICATE: Format of the certificate and which content is to be given in the
certificate itself and which is to be given in an accompanying report.
EXAMPLES Examples of energy certificate formats are given in Annex D.
p) CENTRAL DATABASE: If this is part of the certification procedures, the purpose of this procedure
is to ensure that the data obtained from the energy certificates describing the building stock are
stored in an organized way and in a central place (one database).
4 © ISO 2013 – All rights reserved

5.3 Content of the energy performance certificate
The following administrative and technical data shall be provided according to the setup of the procedure
for building energy certification as specified in 5.2.
a) Administrative data:
1) reference to a specific procedure for building energy certification, including its date;
2) name of person responsible for issuing the energy certificate;
3) address of the building where the energy certificate was issued to;
4) date when the energy certificate was issued and its limit of validity;
b) Technical data:
1) one overall indicator representing the energy performance, as specified in 5.2 under d);
2) type of rating(s) used, as specified in 5.2 under c), adding the following note depending on the
type of rating:
In case of type: Note:
Calculated energy rating
Design rating based on design data
Standard rating based on standard conditions
Tailored rating based on actual data
Measured energy rating based on actual conditions

3) reference values as specified in 5.2 under g);
4) if the certificate is based on design energy rating, the requested additional content as specified
in 5.2 under c);
5) if the certificate is based on measured energy rating, the requested additional content as
specified in 5.2 under c);
6) specific other information on the energy performance of main building and system components,
as specified in 5.2 under h);
7) specific additional indicators, as specified in 5.2 under i);
8) recommendations for cost-effective improvements, as specified in 5.2 under j);
9) energy performance class or other scaling presented on a scale, as specified in 5.2 under k);
10) specific additional content on the certificate to identify the characteristics of the building, as
specified in 5.2 under l).
5.4 Overall energy performance rating types
The procedure for building energy certification shall specify the chosen type or types of rating, as listed
in 5.2 under c), and for which application and building functions.
The types of rating are defined in 5.3 of ISO 16346.
— A) Calculated energy rating, with the following subdivisions:
— A1) Design rating: rating applied to a planned building;
— A2) Standard rating: rating based on standard input data for climate, use, surroundings, and
occupant-related input data;
— A3) Tailored rating: rating calculated with climate, occupancy, and surroundings data adapted
to the actual building and to the purpose of the calculation.
— B) Measured energy rating: rating based on measurement of all energy carriers delivered to the
building and exported by the building and corrected for non-standard conditions, as specified in
Clause 8 of ISO 16346.
If the choice depends on the application and function of the building, this shall be described in the
procedure as part of 5.2 point c).
NOTE Which energy services are included or not is dealt with under 6.1.
Rationale for making the choice:
The selection of the relevant rating type shall take into account the following points.
The procedure for building energy certification shall describe how these points have been taken into
account as part of 5.2 point c).
— For new buildings, the measured energy indicator is not available.
— The utilities which collect data on energy consumption may not be authorized to disclose them for
privacy reasons.
— A measured energy indicator will no longer be valid following a change of building occupier or of the
pattern of use of the building. For existing buildings which are rented or sold, the way the building
is managed could change and the measured energy indicator could change as a result.
— Defining a standard calculated energy indicator includes the collection of data on the building
(insulation, heating system, etc.) which will be useful in giving advice on the improvement of its
energy performance.
— In existing public buildings where there is no change in ownership, the measured energy
indicator can be a measure of the quality of the management and can be used to motivate
building operators and users.
— When the energy certificate is displayed in an existing public building, the operational indicator can be
a measure of the quality of the management and can be used to motivate building operators and users.
— For managers of buildings, a measured energy indicator can be easily obtained from data often
stored in their information systems (energy bills, areas, etc.).
— Measured energy indicator and standard calculated energy indicator do not necessarily include the
same energy uses.
— For new buildings, a design indicator may be the only practical means of assigning an indicator.
The typical application of the different rating types is summarized in Table 3.
6 © ISO 2013 – All rights reserved

Table 3 — Types of ratings
Name Input data Type of application
Use Climate Building
Calculated Design Standard Standard Design Building permit, certificate under condi-
tions
Standard Standard Standard Actual Energy performance certificate, regula-
tion
Tailored Depending on pur- Actual Optimization, validation, retrofit planning
pose
Measured Operational Actual Actual Actual Energy performance certificate, regula-
tion
NOTE When applicable, the presentation of both indicators enables differentiation between the calculated
intrinsic potential of the building represented by the standard calculated energy indicator and the impact of
building management and actual properties of the building and its installations (including control), the effects of
which are included in the measured energy indicator.
5.5 Performance scale
The procedures for building energy certification shall specify the setup and the procedures to assess the
performance scale as part of 5.2 point k).
In addition to the numerical indicator EP, the energy certificate contains energy efficiency classes or
another scaling.
If sufficient information is not available to define the boundaries of classes for a given type of building,
the use of classes or another scaling may be postponed until sufficient data becomes available.
The energy class for a given building shall be based on the value of the energy performance indicator.
A procedure to neutralize or reduce the impact of certain parameters on the energy class can be used by
modifying some parameters used in the calculation of EP as described in 7.3.
Unless differently defined by the developer of the procedure for building energy certification, the
following applies as specified in 5.2 under k).
— The performance scale shall range from A (buildings of highest energy performance) to G (buildings
of lowest energy performance).
— The energy performance regulation reference, R , shall be placed at the boundary between
r
classes B and C.
— The building stock reference, R , shall be placed at the boundary between classes D and E.
s
— A building with a net delivered energy equal to 0 shall be placed at the top of class A.
— Subclasses can be defined in order to subdivide the classes, e.g. class A can be split between A*, A**, A***.
The procedure for building energy certification shall describe the limits of each class, to be specified in
5.2 under k).
NOTE 1 Annex C (informative) provides a procedure for building classification.
NOTE 2 This means that for a given country or region and a given building type, most buildings completed
from 2006 onwards should be in classes A and B, approximately 50 % of the building stock will be in classes
between A and D, and approximately 50 % of the building stock will be in classes E, F, and G.
NOTE 3 Annex D (informative) provides example descriptions of an energy certificate.
5.6 Recommendations
The procedures for building energy certification shall specify the procedures to assess the
recommendations for cost-effective improvements and for which applications these are required on the
certificate, as part of 5.2 point j).
The energy certificate shall contain, if applicable, recommendations dealing with:
a) modernisation measures (building envelope, technical systems);
b) measures of property management (improvement of the operation and control of building and
technical systems).
The assessment of the impact of possible measures can be done according to ISO 16346.
6 Energy performance indicators
6.1 Overall indicator
The procedures for building energy certification shall specify the energy performance indicator or
indicators and for which applications these are required on the certificate, as part of 5.2 points d), e), and i).
The energy performance of a building is represented by an overall indicator, EP, that is the weighted sum
of the delivered and exported energy per energyware determined according to Clause 5 of ISO 16346,
normalized according to 6.4.
The procedure for building energy certification shall describe whether EP represents the following:
a) primary energy (E );
p
b) CO emissions (m );
2 CO2
c) net delivered energy weighted by any other parameter defined by national energy policy (e.g.
delivered energy, E , or cost).
p
The calculated energy rating shall include energy use for heating, cooling, ventilation, and hot water.
The procedure for building energy certification shall describe [as part of 5.2 point i)] if lighting is included
or not. The procedure for building energy certification shall also describe [as part of 5.2 point i)] if energy
for other services is included, for instance, transport of people (elevators, escalators) and/or appliances.
6.2 Other indicators
The procedure for building energy certification shall describe if this overall indicator EP is complemented
by other indicators, in which case, these are to be specified as part of 5.2 point i). In case specific
requirements are defined (see 7.1), appropriate indicators to check compliance with the requirements
shall be specified.
EXAMPLE Thermal performance of the building envelope. See also 7.1 and Annex E.
6.3 Indicator basis
The indicators shall be based on one of the types of ratings chosen under 5.4, to be specified as part of
5.2 point i).
6.4 Normalization of energy rating
The overall indicator, EP, is the rating defined in ISO 16346, divided by the conditioned area, A .
C
8 © ISO 2013 – All rights reserved

The procedures for building energy certification shall specify [as part of 5.2 point e)] the type of
dimensions used to calculate A : internal dimension, external dimension, or overall internal dimension.
C
Rationale for making the choice:
NOTE 1 The type of dimension used has a high impact on the indicator obtained after normalization. For a
house of 10 m × 10 m, the indicator obtained using internal dimensions could be 20 % larger than the one obtained
with external dimensions.
NOTE 2 Usually, the choice is the same as for the calculation of the transmission heat transfer (see
ISO 13789:2007); in addition, there is a direct correlation with input parameters that are related to the conditioned
area (e.g. conventional hot water demand, minimum ventilation, lighting).
NOTE 3 An estimate of A can be obtained from the conditioned volume and mean floor height.
C
7 Expression of energy requirements
7.1 Ways of expressing the requirements
The procedures for building energy certification shall specify [as part of 5.2 point f)] the way or ways
the energy performance requirements are defined and for which applications.
Two main types of requirements can be defined:
a) overall energy performance requirement in accordance with 7.2;
b) specific requirements based on the following:
1) energy use for one specific purpose (e.g. heating, domestic hot water, cooling, lighting,
ventilation);
2) energy need for heating domestic hot water and cooling;
3) characteristics of the building itself or of its technical building systems considered as a whole
(e.g. heat transfer coefficient of the building envelope, heating, hot water or cooling system,
efficiency of lighting systems);
4) characteristics of the building envelope or technical building systems components (e.g.
thermal transmittance of walls, efficiency of boilers, insulation of heating and hot water pipes,
specific fan power).
NOTE 1 Information on possible specific requirements is given in Annex E.
An overall indicator may be combined with specific requirements.
Rationale for making the choice:
NOTE 2 Reasons for doing that include:
a) to avoid too large trade-offs between the performance of the building envelope and the performance
of the technical systems;
b) to avoid technical health or discomfort risks;
c) to prevent components with low performance to be put on the market.
See Reference [2] for more background information on the advantages and disadvantages of additional
requirements.
The indicators used can be different for:
— a new building;
— renovation of an existing building;
— an extension to an existing building;
— different types of buildings.
For new buildings and major renovations, the requirement shall include one overall energy performance
requirement expressed according to 7.2.
For partial renovation of existing buildings and for extension to an existing building where overall
requirements can be difficult to apply, simplified approaches based on specific requirements can be used.
When specifying these requirements, consideration shall be given to the following important energy uses:
— thermal characteristics of the building envelope;
— heating installation and hot water supply;
— air conditioning installation (including dehumidification);
— ventilation (including humidification);
— built-in lighting installation;
— passive solar heat sources and solar protection;
— energy production, particularly by renewable sources and co-generation.
7.2 Overall energy performance requirements
The procedures for building energy certification shall specify [as part of 5.2 point f)] the way the overall
energy performance requirements are defined, particularly in case of buildings with more than one
function with different requirements.
The overall energy requirement, EP , shall be a limit value of the overall energy performance indicator,
r
EP, defined in 6.4.
The requirement is written as
EP ≤ EP (1)
r
where
EP is the overall performance indicator;
EP is the limit value which defines the requirement.
r
When a given building has different functions, k, (e.g. education + sport) with different requirements,
EP , procedures shall be defined to weight the different requirements.
r,k
Unless differently defined by the developer of the procedure for building energy certification, as specified
in 5.2 under f), Formula (2) applies:
n
AE⋅ P
∑ ck,,rk
k=1
EP = (2)
r
A
c
where
k represents the functions: k = 1, 2, ., n.
10 © ISO 2013 – All rights reserved

The conditioned area of a space that is commonly used for more than one building function shall be
proportionally divided over the conditioned areas of these building functions.
7.3 Modification of the impact of certain parameters
7.3.1 General
The procedures for building energy certification shall specify [as part of 5.2 point f)] the way the impact
of certain parameters is modified.
The requirements can be written so as to modify (e.g. reduce, neutralize, correct, or normalize) the
impact of some parameters. These parameters can include those listed in Table 4.
Table 4 — Parameters with reduced or neutralized impacts
Parameter Possible reason
Climate To adapt the level of technologies requested to the climate
Building function To adapt the requirements to the different design, occupation, and feasible tech-
nologies
Energyware For national energy policy regarding the possible use of different energy sources
(e.g. gas/ electricity) or to take into account the availability of specific energy
sources in specific locations
Building size To avoid unduly onerous requirements on detached houses and too low require-
and/or shape ments on large compact buildings
To adapt the requirements to buildings with different sizes and shapes
Ventilation rate To prevent too costly requirements for building/occupation which requires a high
ventilation rate
Illumination To prevent too costly requirements for building/occupation which requires a high
level illumination level
The impact of a parameter can be modified either by specifying particular values or procedures for
the data used in the calculation of EP [see 7.3.1, item a)] or by adjustment of the energy performance
requirement, EP , [see 7.3.1, item b)].
r
a) Standard values for climate and occupant-related input are defined as described in 8.3.2 of ISO 16346.
b) EP can be made dependent upon the parameters whose impact is to be reduced. In this case, EP
r r
may be defined by either
1) the formula approach wherein EP is defined by a simple formula, e.g. EP = f (climate, building
r r
form and function, etc.), or
2) the notional building approach wherein EP is the value of EP calculated for a building having the
r
same location, building function, size, etc. but with parameters such as insulation level, heating
system efficiency, activity schedules, internal heat gains etc. replaced by reference values.
NOTE See Reference [2] for more background information on different reasons and ways to neutralize the
impact of certain parameters and the consequences.
7.3.2 Impact of building shape
The building shape is characterized by the building shape factor:
fA= /A (3)
EC
or the compactness ratio
cA= /V (4)
EC
where
A is the thermal envelope area, in m ;
E
A is the conditioned area, in m ;
C
V is the conditioned volume, in m .
c
The impact of the building shape is taken into account by introducing the building shape factor or the
compactness ratio in the formula expressing EP .
r
EXAMPLE EP = EP (a + b·f ), where a and b are non-dimensional coefficients.
r o
7.3.3 Evolution of the requirements
The requirements can be modified throughout time by writing EP in the following way:
r
EP =⋅α EP (5)
rr,date
where
α is a strengthening factor between 0 and 1, which evolves with time;
EP corresponds to the value of EP at a given date.
r,date r
7.4 Renovation of and extensions to existing buildings
The procedures for building energy certification shall specify [as part of 5.2 point f)] the way the
requirements are expressed in case of renovations of and extensions to existing buildings.
In case of a minor renovation or extension, dealing with few single components or subsystems, e.g. windows,
boilers, artificial lighting installation, the requirements are set at the component or subsystem level.
In case of large renovation, the overall energy performance indicator shall be used but the procedures
for building energy certification may specify higher values of EP than for new buildings.
r
In case of large extension, the overall energy performance indicator shall be used but the procedures for
building energy certification may specify distinct values of EP for the existing part and the new part.
r
When the notional or reference building approach is used, the pe
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