EN ISO 10077-1:2017

SLOVENSKI STANDARD
01-september-2017
1DGRPHãþD
SIST EN ISO 10077-1:2007
SIST EN ISO 10077-1:2007/AC:2010
7RSORWQH]QDþLOQRVWLRNHQYUDWLQSRONHQ,]UDþXQWRSORWQHSUHKRGQRVWLGHO
6SORãQR,62
Thermal performance of windows, doors and shutters - Calculation of thermal
transmittance - Part 1: General (ISO 10077-1:2017)
Wärmetechnisches Verhalten von Fenstern, Türen und Abschlüssen - Berechnung des
Wärmedurchgangskoeffizienten - Teil 1: Allgemeines (ISO 10077-1:2017)
Performance thermique des fenêtres, portes et fermetures - Calcul du coefficient de
transmission thermique - Partie 1: Généralités (ISO 10077-1:2017)
Ta slovenski standard je istoveten z: EN ISO 10077-1:2017
ICS:
91.060.50 Vrata in okna Doors and windows
91.120.10 Toplotna izolacija stavb Thermal insulation of
buildings
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 10077-1
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2017
EUROPÄISCHE NORM
ICS 91.060.50; 91.120.10 Supersedes EN ISO 10077-1:2006
English Version
Thermal performance of windows, doors and shutters -
Calculation of thermal transmittance - Part 1: General (ISO
10077-1:2017)
Performance thermique des fenêtres, portes et Wärmetechnisches Verhalten von Fenstern, Türen und
fermetures - Calcul du coefficient de transmission Abschlüssen - Berechnung des
thermique - Partie 1: Généralités (ISO 10077-1:2017) Wärmedurchgangskoeffizienten - Teil 1: Allgemeines
(ISO 10077-1:2017)
This European Standard was approved by CEN on 27 February 2017.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 10077-1:2017 E
worldwide for CEN national Members.

EN ISO 10777-1:2017 (E)
Contents Page
European foreword . 3

EN ISO 10777-1:2017 (E)
European foreword
This document (EN ISO 10777-1:2017) has been prepared by Technical Committee CEN/TC 89
“Thermal performance of buildings and building components”, the secretariat of which is held by SIS, in
collaboration with Technical Committee ISO/TC 163 "Thermal performance and energy use in the built
environment".
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by January 2018 and conflicting national standards shall
be withdrawn at the latest by January 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
This document is part of the set of standards on the energy performance of buildings (the set of EPB
standards) and has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association (Mandate M/480, see reference [EF1] below), and supports essential
requirements of EU Directive 2010/31/EC on the energy performance of buildings (EPBD, [EF2]).
In case this standard is used in the context of national or regional legal requirements, mandatory
choices may be given at national or regional level for such specific applications, in particular for the
application within the context of EU Directives transposed into national legal requirements.
Further target groups are users of the voluntary common European Union certification scheme for the
energy performance of non-residential buildings (EPBD art.11.9) and any other regional (e.g. Pan
European) parties wanting to motivate their assumptions by classifying the building energy
performance for a dedicated building stock.
This document supersedes EN ISO 10077-1:2006.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands,
Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
the United Kingdom.
References:
[EF1] Mandate M480, Mandate to CEN, CENELEC and ETSI for the elaboration and adoption of
standards for a methodology calculating the integrated energy performance of buildings and
promoting the energy efficiency of buildings, in accordance with the terms set in the recast of the
Directive on the energy performance of buildings (2010/31/EU) of 14th December 2010
th
[EF2] EPBD, Recast of the Directive on the energy performance of buildings (2010/31/EU) of 14
December 2010.
EN ISO 10777-1:2017 (E)
Endorsement notice
The text of ISO 10777-1:2017 has been approved by CEN as EN ISO 10777-1:2017 without any
modification.
INTERNATIONAL ISO
STANDARD 10077-1
Third edition
2017-06
Thermal performance of windows,
doors and shutters — Calculation of
thermal transmittance —
Part 1:
General
Performance thermique des fenêtres, portes et fermetures — Calcul
du coefficient de transmission thermique —
Partie 1: Généralités
Reference number
ISO 10077-1:2017(E)
©
ISO 2017
ISO 10077-1:2017(E)
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

ISO 10077-1:2017(E)
Contents Page
Foreword .iv
Introduction .vi
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 3
4 Symbols and subscripts . 3
4.1 Symbols . 3
4.2 Subscripts . 4
5 Description of the method . 4
5.1 Output of the method . 4
5.2 General description . 4
5.3 Other general topics . 5
6 Calculation of thermal transmittance . 5
6.1 Output data . 5
6.2 Calculation time intervals . 5
6.3 Input data . 5
6.3.1 Geometrical characteristics . 5
6.3.2 Thermal characteristics . 8
6.4 Calculation procedure .11
6.4.1 Applicable time interval .11
6.4.2 Calculation of thermal transmittance .11
7 Test report .17
7.1 Contents of test report .17
7.2 Drawing of sections .18
7.2.1 Drawing of the whole window or door.18
7.2.2 Values used in the calculation .18
7.2.3 Presentation of results .18
Annex A (normative) Input and method selection data sheet — Template .19
Annex B (informative) Input and method selection data sheet — Default choices .21
Annex C (normative) Regional references in line with ISO Global Relevance Policy .23
Annex D (normative) Internal and external surface thermal resistances.24
Annex E (normative) Thermal resistance of air spaces between glazing and thermal
transmittance of coupled, double or triple glazing .25
Annex F (normative) Thermal transmittance of frames .26
Annex G (normative) Linear thermal transmittance of frame/glazing junction and glazing bars .32
Annex H (normative) Thermal transmittance of windows .36
Bibliography .41
ISO 10077-1:2017(E)
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 (see 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 (see 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.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO’s adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: w w w . i s o .org/ iso/ foreword .html.
ISO 10077-1 was prepared by the European Committee for Standardization (CEN) Technical
Committee CEN/TC 89, Thermal performance of buildings and building components, in collaboration
with ISO Technical Committee TC 163, Thermal performance and energy use in the built environment,
Subcommittee SC 2, Calculation methods, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 10077-1:2006), of which it constitutes a
minor revision. The necessary editorial revisions were made to comply with the requirements for the
EPB set of standards.
In addition, the following clauses and subclauses of the previous version have been revised.
— In Clause 6 (previous edition), the boundary condition “determined with the glazing replaced with
a material of thermal conductivity not exceeding 0,04 W/(m ·K)” was deleted, because the rules are
defined in EN 12412-2.
— In Clause 6 (previous edition), the measurement according to EN 12412-2 for the determination of
Ψ and/or Ψ was deleted. It is not within the scope of EN 12412-2 to determine Ψ values.
g p
— In Clause 6 (previous edition), the second paragraph was deleted. It is not necessary to give further
possibilities. Determination of the input data in unambiguous is defined.
1)
— In 5.2.2 (previous edition), the formula was deleted. Determination of U is according to ISO 10292.
g
— Formulae (1) and (2) were extended for the consideration of glazing bars.
— Tabulated values were added for the linear thermal transmittance of glazing bars.
— Status of Annex C (previous edition) was changed to normative; some values were revised to give
the values to two significant figures.
1) See Table C.1 for alternative regional references in line with ISO Global Relevance Policy.
iv © ISO 2017 – All rights reserved

ISO 10077-1:2017(E)
— Table C.2 (previous edition) was moved to ISO/TR 52022-2:2017.
— Annex E (previous edition) was moved to the main body of the document.
— Annex G and Annex H (previous edition) were moved to ISO/TR 52022-2:2017.
It also incorporates the Technical Corrigendum ISO 10077-1:2006/Cor. 1:2009.
A list of all parts in the ISO 10077 series can be found on the ISO website.
ISO 10077-1:2017(E)
Introduction
This document is part of a series of standards aiming at international harmonization of the methodology
for the assessment of the energy performance of buildings, called “set of EPB standards.”
All EPB standards follow specific rules to ensure overall consistency, unambiguity and transparency.
All EPB standards provide a certain flexibility with regard to the methods, the required input data and
references to other EPB standards, by the introduction of a normative template in Annex A and Annex B
with informative default choices.
For the correct use of this document, a normative template is given in Annex A to specify these choices.
Informative default choices are provided in Annex B.
The main target groups of this document are manufacturers of windows.
Use by or for regulators: In case the document is used in the context of national or regional legal
requirements, mandatory choices may be given at national or regional level for such specific
applications. These choices (either the informative default choices from Annex B or choices adapted to
national/regional needs, but in any case, following the template in Annex A) can be made available as
national annex or as separate (e.g. legal) document (national data sheet).
NOTE 1 So in this case:
— the regulators will specify the choices;
— the individual user will apply the standard to assess the energy performance of a building, and thereby use
the choices made by the regulators.
Topics addressed in this document can be subject to public regulation. Public regulation on the same
topics can override the default values in Annex B. Public regulation on the same topics can even, for
certain applications, override the use of this document. Legal requirements and choices are in general
not published in standards but in legal documents. In order to avoid double publications and difficult
updating of double documents, a national annex may refer to the legal texts where national choices
have been made by public authorities. Different national annexes or national data sheets are possible,
for different applications.
It is expected, if the default values, choices and references to other EPB standards in Annex B are not
followed due to national regulations, policy or traditions, that
— national or regional authorities prepare data sheets containing the choices and national or regional
values, according to the model in Annex A. In this case, a national annex (e.g. NA) is recommended,
containing a reference to these data sheets;
— or, by default, the national standards body will consider the possibility to add or include a national
annex in agreement with the template in Annex A, in accordance to the legal documents that give
national or regional values and choices.
Further target groups are parties wanting to motivate their assumptions by classifying the building
energy performance for a dedicated building stock.
More information is provided in the Technical Report accompanying this document (ISO/TR 52022-2).
The calculation method described in this document is used to evaluate the thermal transmittance of
windows and doors, or as part of the determination of the energy use of a building.
An alternative to calculation is testing of the complete window or door according to ISO 12567-1 or, for
roof windows, according to ISO 12567-2.
vi © ISO 2017 – All rights reserved

ISO 10077-1:2017(E)
The calculation is based on four component parts of the overall thermal transmittance:
— for elements containing glazing, the thermal transmittance of the glazing, calculated using EN 673
or measured according to EN 674 or EN 675;
— for elements containing opaque panels, the thermal transmittance of the opaque panels, calculated
according to ISO 6946 and/or ISO 10211 (all parts) or measured according to ISO 8301 or ISO 8302;
— thermal transmittance of the frame, calculated using ISO 10077-2, measured according to EN 12412-
2, or taken from Annex D;
— linear thermal transmittance of the frame/glazing junction, calculated according to ISO 10077-2 or
taken from Annex E.
The thermal transmittance of curtain walling can be calculated using ISO 12631.
EN 13241-1 gives procedures applicable to doors intended to provide access for goods and vehicles.
Table 1 shows the relative position of this document within the set of EPB standards in the context of
the modular structure as set out in ISO 52000-1.
NOTE 2 In ISO/TR 52000-2, the same table can be found, with, for each module, the numbers of the relevant
EPB standards and accompanying technical reports that are published or in preparation.
NOTE 3 The modules represent EPB standards, although one EPB standard could cover more than one module
and one module could be covered by more than one EPB standard, for instance, a simplified and a detailed method
respectively.
Table 1 — Position of this document (in case M2–5) within the modular structure of the set of
EPB standards
Building
Overarching Technical Building Systems
(as such)
Do- Building
Sub- Ven- Dehu- PV,
Descrip- Descrip- Descrip- Heat- Cool- Humidi- mestic automa-
mod- tila- midifi- Lighting wind,
tions tions tions ing ing fication hot tion and
ule tion cation .
water control
sub1 M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11
1 General General General
Common
terms and
Building
definitions;
a
2 energy Needs
symbols,
needs
units and
subscripts
(Free)
Maxi-
indoor
mum
3 Applications conditions
load and
without
power
systems
Ways to Ways to
Ways to ex- express express
4 press energy energy energy
performance perfor- perfor-
mance mance
Building Heat
Emission
categories transfer by
5 ISO 10077-1 and
and building transmis-
control
boundaries sion
a
The shaded modules are not applicable.
ISO 10077-1:2017(E)
Table 1 (continued)
Building
Overarching Technical Building Systems
(as such)
Do- Building
Sub- Ven- Dehu- PV,
Descrip- Descrip- Descrip- Heat- Cool- Humidi- mestic automa-
mod- tila- midifi- Lighting wind,
tions tions tions ing ing fication hot tion and
ule tion cation .
water control
sub1 M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11
Heat
Building oc-
transfer by Distribu-
cupancy and
6 infiltration tion and
operating
and venti- control
conditions
lation
Aggregation
of energy Storage
Internal
7 services and
heat gains
and energy control
carriers
Genera-
Building Solar heat
8 tion and
zoning gains
control
Load dis-
Building patching
Calculated
dynamics and op-
9 energy per-
(thermal erating
formance
mass) condi-
tions
Meas-
Measured
Measured ured
energy
10 energy per- Energy
perfor-
formance Perfor-
mance
mance
Inspec-
11 Inspection Inspection
tion
Ways to ex-
12 press indoor BMS
comfort
External
13 environment
conditions
Economic
calculation
a
The shaded modules are not applicable.
viii © ISO 2017 – All rights reserved

INTERNATIONAL STANDARD ISO 10077-1:2017(E)
Thermal performance of windows, doors and shutters —
Calculation of thermal transmittance —
Part 1:
General
1 Scope
This document specifies methods for the calculation of the thermal transmittance of windows and
pedestrian doors consisting of glazed and/or opaque panels fitted in a frame, with and without shutters.
This document allows for
— different types of glazing (glass or plastic; single or multiple glazing; with or without low emissivity
coatings, and with spaces filled with air or other gases),
— opaque panels within the window or door,
— various types of frames (wood, plastic, metallic with and without thermal barrier, metallic with
pinpoint metallic connections or any combination of materials), and
— where appropriate, the additional thermal resistance introduced by different types of closed shutter
or external blind, depending on their air permeability.
The thermal transmittance of roof windows and other projecting windows can be calculated according
to this document, provided that the thermal transmittance of their frame sections is determined by
measurement or by numerical calculation.
Default values for glazing, frames and shutters are given in the annexes. Thermal bridge effects at the
rebate or joint between the window or door frame and the rest of the building envelope are excluded
from the calculation.
The calculation does not include
— effects of solar radiation (see standards under M2-8),
— heat transfer caused by air leakage (see standards under M2-6),
— calculation of condensation,
— ventilation of air spaces in double and coupled windows, and
— surrounding parts of an oriel window.
The document is not applicable to
— curtain walls and other structural glazing (see other standards under M2-5), and
— industrial, commercial and garage doors.
NOTE Table 1 in the Introduction shows the relative position of this document within the set of EPB
standards in the context of the modular structure as set out in ISO 52000-1.
ISO 10077-1:2017(E)
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 6946, Building components and building elements — Thermal resistance and thermal transmittance —
Calculation method
ISO 7345, Thermal insulation — Physical quantities and definitions
ISO 8301, Thermal insulation — Determination of steady-state thermal resistance and related properties —
Heat flow meter apparatus
ISO 8302, Thermal insulation — Determination of steady-state thermal resistance and related properties —
Guarded hot plate apparatus
ISO 10077-2, Thermal performance of windows, doors and shutters — Calculation of thermal
transmittance — Part 2: Numerical method for frames
ISO 10211, Thermal bridges in building construction — Heat flows and surface temperatures — Detailed
calculations
ISO 10291, Glass in building — Determination of steady-state U values (thermal transmittance) of multiple
glazing — Guarded hot plate method
ISO 10292, Glass in building — Calculation of steady-state U values (thermal transmittance) of multiple
glazing
ISO 10293, Glass in building — Determination of steady-state U values (thermal transmittance) of multiple
glazing — Heat flow meter method
ISO 10456, Building materials and products — Hygrothermal properties — Tabulated design values and
procedures for determining declared and design thermal values
ISO 12567-2, Thermal performance of windows and doors — Determination of thermal transmittance by
hot box method — Part 2: Roof windows and other projecting windows
ISO 52000-1:2017, Energy performance of buildings — Overarching EPB assessment —– Part 1: General
framework and procedures
EN 673, Glass in building — Determination of thermal transmittance (U value) — Calculation method
EN 674, Glass in building — Determination of thermal transmittance (U value) — Guarded hot plate method
EN 675, Glass in building — Determination of thermal transmittance (U value) — Heat flow meter method
EN 12412-2, Thermal performance of windows, doors and shutters — Determination of thermal
transmittance by hot box method — Frames
EN 12664, Thermal performance of building materials and products — Determination of thermal resistance
by means of guarded hot plate and heat flow meter methods — Dry and moist products of medium and low
thermal resistance
EN 12667, Thermal performance of building materials and products — Determination of thermal resistance
by means of guarded hot plate and heat flow meter methods — Products of high and medium thermal
resistance
EN 13125, Shutters and blinds — Additional thermal resistance — Allocation of a class of air permeability
to a product
EN 13561, External blinds and awnings — Performance requirements including safety
2 © ISO 2017 – All rights reserved

ISO 10077-1:2017(E)
EN 13659, Shutters and external venetian blinds — Performance requirements including safety
NOTE Default references to EPB standards other than ISO 52000-1 are identified by the EPB module code
number and given in Annex A (normative template in Table A.1) and Annex B (informative default choice in
Table B.1).
EXAMPLE EPB module code number: M5–5, or M5–5.1 (if module M5–5 is subdivided), or M5–5/1 (if
reference to a specific clause of the standard covering M5–5).
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 10292, ISO 7345, ISO 52000-1
and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
NOTE In Clause 6, descriptions are given of a number of geometrical characteristics of glazing and frame.
3.1
EPB standard
[3]
standard that complies with the requirements given in ISO 52000-1, CEN/TS 16628 and
[4]
CEN/TS 16629
Note 1 to entry: These three basic EPB documents were developed under a mandate given to CEN by the European
Commission and the European Free Trade Association (Mandate M/480), and support essential requirements of
EU Directive 2010/31/EU on the energy performance of buildings (EPBD). Several EPB standards and related
documents are developed or revised under the same mandate.
[SOURCE: ISO 52000-1:2017, definition 3.5.14]
4 Symbols and subscripts
4.1 Symbols
For the purposes of this document, the symbols given in ISO 52000-1 and the following apply.
Symbol Name of quantity Unit
A area m
R thermal resistance m ⋅K/W
U thermal transmittance W/(m ⋅K)
b width m
d distance, thickness m
l length m
q density of heat flow rate W/m
Ψ linear thermal transmittance W/(m⋅K)
λ thermal conductivity W/(m⋅K)
ISO 10077-1:2017(E)
4.2 Subscripts
For the purposes of this document, the subscripts given in ISO 52000-1 and the following apply.
Subscript Description
D door
W window
WS window with closed shutter or blind
d developed
e external
f frame
g glazing
gb glazing bar
i internal
j summation index
p panel (opaque)
s space (air or gas space)
se external surface
sh shutter or blind
si internal surface
5 Description of the method
5.1 Output of the method
The output of this document is the thermal transmittance of windows and pedestrian doors consisting
of glazed and/or opaque panels fitted in a frame, with and without shutters:
Depending on the type of product or assembly, it is one of the following:
— the thermal transmittance of a single window, U ;
W
— the thermal transmittance, U , of a system consisting of two separate windows;
W
— the thermal transmittance, U , of a system consisting of one frame and two separate sashes or
W
casements;
— the thermal transmittance of a window with closed shutters or external blinds, U ;
WS
— the thermal transmittance, U , of a door set of which the door leaf is fully glazed, or if the door
D
consists of frame, glazing and opaque panels, or if the door has no glazing.
5.2 General description
In general, the thermal transmittance or U-value of the window or door product or assembly is calculated
as a function of the thermal transmittance of the components and their geometrical characteristics,
plus the thermal interactions between the components.
— The calculation procedures depend on the composition of the product or assembly.
— Components may include (where appropriate): glazings, opaque panels, frames, and closed shutters
or external blinds.
— Thermal interactions are lateral heat flow (linear thermal bridge effect) between adjacent
components and surface and cavity thermal resistances (thermal radiation and convection).
4 © ISO 2017 – All rights reserved

ISO 10077-1:2017(E)
— The geometrical characteristics concern the sizes and positions of the components and the tilt angle
of the window or door.
5.3 Other general topics
Results obtained for the purposes of comparison of products (declared values) shall be calculated or
measured for horizontal heat flow.
If design values are taking into account the actual inclination of the window, they shall be determined
for the actual inclination and boundary conditions, by including the effect of the inclination of the
window in the determination of U . However, U and Ψ and/or Ψ as determined for the window in the
g f g p
vertical position are used for all inclinations of the window. The design value is to be calculated only if
it is needed for the calculation of the energy demand of the building.
Throughout this document, where indicated in the text, Table C.1 shall be used to identify alternative
regional references in line with ISO Global Relevance Policy.
6 Calculation of thermal transmittance
6.1 Output data
The outputs of this document are transmission heat transfer coefficients as shown in Table 2.
Table 2 — Output data
Description Symbol Unit Destination Validity Varying
module interval
Thermal transmit- U W/(m ·K) M2-2, M2-3, 0 to ∞ No
W
tance of window M2-4
Thermal transmit- U W/(m ·K) M2-2, M2-3, 0 to ∞ No
D
tance of door M2-4
Thermal transmit- U W/(m ·K) M2-2, M2-3, 0 to ∞ No
WS
tance of window M2-4
with closed shutter
or external blind
6.2 Calculation time intervals
The input, the method and the output data are for steady state conditions and assumed to be independent
of actual conditions, such as indoor and outdoor temperature or effect of wind or solar radiation.
6.3 Input data
6.3.1 Geometrical characteristics
6.3.1.1 General
Table 3 shows the necessary geometrical characteristics.
ISO 10077-1:2017(E)
Table 3 — Identifiers for geometric characteristics
Origin
Name Symbol Unit Range Varying
a
module
Geometrical data
Window or door
Window area A m 0 to ∞ No
W
product or assembly
Window or door
Door area A m 0 to ∞ No
D
product or assembly
Window or door
Glazed area A m 0 to ∞ No
g
product or assembly
Window or door
Frame area A m 0 to ∞ No
f
product or assembly
Window or door
Opaque panel area A m 0 to ∞ No
p
product or assembly
Window or door
Total perimeter of the glazing l m 0 to ∞ No
g
product or assembly
Window or door
Total perimeter of the panel l m 0 to ∞ No
p
product or assembly
Window or door
Total length of the glazing bar l m 0 to ∞ No
gb
product or assembly
a
According to specifications given in 6.3.1.2 to 6.3.1.5.
6.3.1.2 Glazed area, opaque panel area
The glazed area, A , or the opaque panel area, A , of a window or door is the smaller of the visible areas
g p
seen from both sides; see Figure 2. Any overlapping of gaskets is ignored.
6.3.1.3 Total visible perimeter of the glazing
The total perimeter of the glazing, l , (or the opaque panel, l ) is the sum of the visible perimeter of the
g p
glass panes (or opaque panels) in the window or door. If the perimeters are different on either side of
the pane or panel, then the larger of the two shall be used; see Figure 1.
Key
1 glass
Figure 1 — Illustration of glazed area and perimeter
6.3.1.4 Frame areas
For the definition of the areas, see also Figure 2.
6 © ISO 2017 – All rights reserved

ISO 10077-1:2017(E)
A Internal projected frame area:
f,i
The internal projected frame area is the area of the projection of the internal frame, in-
cluding sashes if present, on a plane parallel to the glazing panel.
A External projected frame area:
f,e
The external projected frame area is the area of the projection of the external frame, in-
cluding sashes if present, on a plane parallel to the glazing panel.
A Frame area:
f
The frame area is the larger of the two projected areas seen from both sides.
A Internal developed frame area:
f,di
The internal developed frame area is the area of the frame, including sashes if present, in
contact with the internal air (see Figure 2).
A External developed frame area:
f,de
The external developed frame area is the area of the frame, including sashes if present, in
contact with the external air (see Figure 2).

Key
1 frame
2 glazing
a
Internal.
b
External.
Figure 2 — Internal and external developed area
6.3.1.5 Window area and door area
The window area, A , or the door area, A ; A is the sum of the frame area, A , and the glazing area, A ,
w D f g
(or the panel area, A ).
p
The frame area and the glazed area are defined by the edge of the frame, i.e. sealing gaskets are ignored
for the purposes of determination of the areas.
Window or door dimensions (height, width, frame width and frame thickness) shall be determined to
the nearest millimetre.
ISO 10077-1:2017(E)
Key
1 sash (moveable) A = max (A ; A )
f f,i f,e
2 frame (fixed) A = A + A
w f g
a
Internal A = A + A + A + A .
f,di 1 2 3 4
b
External A = A + A + A + A .
f,de 5 6 7 8
NOTE 1 The frame area, A , includes the area of the fixed frame together with that of any moveable sash or
f
casement.
NOTE 2 Drip trays and similar protuberances are not considered part of the developed area.
Figure 3 — Illustration of the various areas
6.3.2 Thermal characteristics
6.3.2.1 General
Table 4 identifies the thermal characteristics of the window/door components necessary for the
calculation of the thermal transmittance of the window or door.
8 © ISO 2017 – All rights reserved

ISO 10077-1:2017(E)
Table 4 — Identifiers for thermal characteristics of the window/door component
Name Symbol Unit Range Origin Varying
ISO 10077-2 or
Thermal transmittance of frame U W/(m ·K) 0 to ∞ EN 12412-2 or No
f
Annex F
ISO 10291 for measured value
(GHP), ISO 10292 for calcu-
Thermal transmittance of glazing U W/(m ·K) 0 to ∞ lated value or ISO 10293 for No
g
measured value (HFM) (or see
Subject 1, 2 or 3 in Table C.1)
Linear thermal transmittance due to
Annex G or
combined effect of glazing, spacer and Ψ W/(m·K) 0 to ∞ No
g
ISO 10077-2
frame
ISO 6946 or
Thermal transmittance of opaque panel U W/(m ·K) 0 to ∞ ISO 10211 or No
p
EN 12664/EN 12667
Linear thermal transmittance due to
Ψ W/(m·K) 0 to ∞ ISO 10077-2 No
p
combined effect of panel, spacer and frame
Annex G or
Linear thermal transmittance due to
Ψ W/(m·K) 0 to ∞ No
gb
combined effect of glazing bar and glazing
ISO 10077-2
6.3.2.2 Frame
The thermal transmittance of the frame, U , shall be by hot box measurement in accordance with
f
EN 12412-2 or numerical calculation in accordance with ISO 10077-2.
U for roof windows shall be either
f
— calculated in accordance with ISO 10077-2, or
— measured in accordance with EN 12412-2 with specimens mounted within the aperture in the
surround panel flush with the cold side, in accordance with in ISO 12567-2.
For other windows, U shall be
f
— calculated in accordance with ISO 10077-2,
— measured in accordance with EN 12412-2, or
— obtained from Annex G.
6.3.2.3 Glazing
6.3.2.3.1 Single glazing
The thermal transmittance of a single or a single laminated glazing, U , shall be calculated using
g
Formula (1):
U = (1)
g
d
j
R ++R
∑
se si
j
λ
j
where
ISO 10077-1:2017(E)
R is the external surface resistance;
se
λ is the thermal conductivity of glass or material layer j;
j
d is the thickness of the glass pane or material layer j;
j
R is the internal surface resistance.
si
In the absence of specific information for the glass concerned, the value λ = 1,0 W/(m⋅K) shall be used.
6.3.2.3.2 Multiple glazing
The thermal transmittance of multiple glazing, Ug, shall be determined in accordance with ISO 10291
for measured value (GHP), ISO 10292 for calculated value or ISO 10293 for measured value (HFM) (or
see Subject 1, 2 or 3 in Table C.1).
6.3.2.4 Panel/door leaves
The thermal transmittance of panels or opaque door leaves excluding the frame and without
inhomogeneities (having different layers only perpendicular to the heat flow direction) can be
measured in the heat-flow meter apparatus in accordance with ISO 8301 or in the guarded hot-plate
apparatus, in accordance with ISO 8302. Alternatively, EN 12664 or EN 12667 may be used. Formula (8)
is used to calculate the thermal transmittance of the door set, with A = 0.
g
Alternatively, the thermal transmittance of door leaves can be calculated in accordance with ISO 6946
provided that the ratio of the thermal conductivities of any two different materials in the door does not
exceed 1:5 (screws, nails and so on are exclud
...