IEC 60379:2023

Methods for measuring the performance of electric storage water heaters for household purposes

IEC 60379:2023 specifies methods for measuring the performance of electric storage water heaters to produce domestic potable or non-potable hot water for household and similar use.
The object is to state and define the principal performance characteristics of electric storage water heaters and to describe the test methods for measuring these characteristics.
This document does not apply to;
- storage water heaters that use electricity as a secondary source of heating the water;
- storage water heaters that do not use a tank to store hot water;
- electric storage water heaters that do not meet the minimum (or maximum) output performance of the smallest (or biggest) load profile, as defined in Table 3;
- water-heaters without thermal insulation.
This document does not specify safety requirements. For safety requirements, see IEC 60335-1 in conjunction with IEC 60335-2-21.
This fourth edition cancels and replaces the third edition published in 1987. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition: sustainable development aspects of EU legislation are taken into account, including features such as smart control, V40 modification and measuring procedures for multi-tank appliances.

Méthodes de mesure de l'aptitude à la fonction des chauffe-eau électriques à accumulation à usages domestiques

L'IEC 60379:2023 spécifie les méthodes de mesure de l'aptitude à la fonction des chauffe-eau électriques à accumulation pour produire de l'eau chaude sanitaire potable ou non potable pour usages domestiques et analogues.
L'objet du présent document est d'établir et de définir les caractéristiques de performance principales des chauffe-eau électriques à accumulation et de décrire les méthodes d'essai utilisées pour mesurer ces caractéristiques.
Le présent document ne s'applique pas:
- aux chauffe-eau à accumulation qui utilisent l'électricité comme source secondaire pour chauffer l'eau;
- aux chauffe-eau à accumulation qui n'utilisent pas de ballon pour stocker l'eau chaude;
- aux chauffe-eau électriques à accumulation qui ne remplissent pas les caractéristiques de sortie minimales (ou maximales) du profil de charge le plus faible (ou le plus élevé), qui est défini dans le Tableau 3;
- aux chauffe-eau sans isolation thermique.
Le présent document ne spécifie pas les exigences de sécurité. Pour les exigences de sécurité, consulter l'IEC 60335-1 conjointement avec l'IEC 60335-2-21.
Cette quatrième édition annule et remplace la troisième édition parue en 1987. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: prise en compte des aspects de la réglementation UE en matière de développement durable, notamment les fonctions telles que la commande intelligente, la modification de V40 et les procédures de mesurage relatives aux appareils à ballons multiples.

General Information

• Status: Published
• Publication Date: 06-Feb-2023
• ICS: 91.140.65 - Water heating equipment
• Technical Committee: SC 59C - Electrical heating appliances for household and similar purposes
• Drafting Committee: MT 1 - TC 59/SC 59C/MT 1
• Current Stage: PPUB - Publication issued
• Start Date: 10-Mar-2023
• Completion Date: 07-Feb-2023

Standards Content (Sample)

IEC 60379
®

Edition 4.0 2023-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Methods for measuring the performance of electric storage water heaters for
household purposes

Méthodes de mesure de l'aptitude à la fonction des chauffe-eau électriques à
accumulation à usages domestiques

IEC 60379:2023-02(en-fr)

---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60379

®


Edition 4.0 2023-02




INTERNATIONAL



STANDARD




NORME


INTERNATIONALE
colour

inside










Methods for measuring the performance of electric storage water heaters for

household purposes



Méthodes de mesure de l'aptitude à la fonction des chauffe-eau électriques à

accumulation à usages domestiques

















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 91.140.65 ISBN 978-2-8322-6439-3




Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

---------------------- Page: 3 ----------------------
– 2 – IEC 60379:2023 © IEC 2023
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols and units . 9
5 Calculation of the electrical energy efficiency (η ) . 10
elecwh
6 Measured parameters . 10
7 General conditions for measurements . 10
8 Reference conditions . 12
9 Test procedures . 15
9.1 Standard test procedure. 15
9.1.1 General . 15
9.1.2 Installation . 15
9.1.3 Stabilisation . 15
9.1.4 Storage volume . 16
9.1.5 Filling and heat-up . 16
9.1.6 Stabilisation at zero-load and cyclic temperature variation (differential) . 17
9.1.7 Tapping . 17
9.1.8 Reporting of Q . 18
elec
9.1.9 Re-stabilisation at zero-load . 18
9.1.10 Mixed water quantity delivered at 40 °C . 18
9.2 Smart control test procedure . 20
9.2.1 Measurement procedure . 20
9.2.2 Installation . 20
9.2.3 Stabilisation . 20
9.2.4 Filling and heat-up . 20
9.2.5 Stabilisation before reference period . 21
9.2.6 Reference period . 21
9.2.7 Smart period . 22
9.2.8 Reporting of the smart control factor . 23
9.2.9 WHL control cycle . 23
9.3 Measurement of stored water temperatures . 23
9.4 Thermostat setting . 24
9.5 Standing loss per 24 h . 25
9.5.1 General . 25
9.5.2 Single-tank standing loss . 25
9.5.3 Multi-tank standing loss for directly measurable products . 25
9.5.4 Multi-tank standing loss for not directly measurable products . 27
9.6 Hot water output . 29
9.7 Maximum hot water output . 29
10 Data report . 30
Annex A (normative) Calculation of the specific energy efficiency and of the annual
consumption of electric energy . 32
A.1 Symbols and units . 32
A.2 Calculation of the specific energy efficiency . 32

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IEC 60379:2023 © IEC 2023 – 3 –
A.3 Calculation of the annual consumption of electric energy . 33
A.4 Data report . 33
Annex B (normative) Test setup . 34

Figure 1 – Test procedure for "energized appliances" . 15
Figure 2 – Test procedure for "off-peak appliances" . 15
Figure 3 – Test procedure for "smart cycle" . 20
Figure 4 – Assembly scheme . 27
Figure 5 – Assembly scheme BENCH . 28
Figure B.1 – Schematic representation of storage water-heaters. 35
Figure B.2 – Position of the thermocouples for vertical and horizontal models . 36
Figure B.3 – Example of hydraulic connection (unvented products) . 37
Figure B.4 – Schemes for directly measurable multi-tank appliances . 38
Figure B.5 – Directly measurable multi tank . 39
Figure B.6 – Not directly measurable multi tank . 39

Table 1 – Electricity . 11
Table 2 – Test conditions, outputs, set values and tolerances. . 11
Table 3 – Load profile of the water heater (reference test tapping patterns) . 13
Table 4 – Tolerance of the rated storage volume . 16
Table 5 – Tapping profiles . 21
Table 6 – Rated capacity and flow rates . 29
Table 7 – Data report . 31
Table A.8 – k values . 33
Table A.9 – Complements to data report . 33
Table B.1 – Thickness of insulation according to size of pipe or connection . 40

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– 4 – IEC 60379:2023 © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

METHODS FOR MEASURING THE PERFORMANCE
OF ELECTRIC STORAGE WATER HEATERS
FOR HOUSEHOLD PURPOSES

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 60379 has been prepared by subcommittee SC59C: Electrical heating appliances for
household and similar purposes, of IEC technical committee 59: Performance of household and
similar electrical appliances. It is an International Standard.
This fourth edition cancels and replaces the third edition published in 1987. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) sustainable development aspects of EU legislation are taken into account, including features
such as smart control, V modification and measuring procedures for multi-tank appliances.
40

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IEC 60379:2023 © IEC 2023 – 5 –
The text of this International Standard is based on the following documents:
Draft Report on voting
59C/282/FDIS 59C/285/RVD

Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The "colour inside" logo on the cover page of this document indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

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– 6 – IEC 60379:2023 © IEC 2023
METHODS FOR MEASURING THE PERFORMANCE
OF ELECTRIC STORAGE WATER HEATERS
FOR HOUSEHOLD PURPOSES



1 Scope
This document specifies methods for measuring the performance of electric storage water
heaters to produce domestic potable or non-potable hot water for household and similar use.
The object is to state and define the principal performance characteristics of electric storage
water heaters and to describe the test methods for measuring these characteristics.
NOTE 1 This document does not apply to:
• storage water heaters that use electricity as a secondary source of heating the water;
• storage water heaters that do not use a tank to store hot water;
• electric storage water heaters that do not meet the minimum (or maximum) output performance of the smallest
(or biggest) load profile, as defined in Table 3;
• water-heaters without thermal insulation.
NOTE 2 This document does not specify safety requirements. For safety requirements, see IEC 60335-1 in
conjunction with IEC 60335-2-21.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
storage water heater
water heater that uses electric heating elements as the means of heating water for long-term
storage in a thermally insulated container and provided with a device to control the water
temperature
3.2
primary function
production of hot water for household and similar needs
3.3
energized storage water heater
storage water heater that is designed to supply hot water and be energized for 24 h per day

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IEC 60379:2023 © IEC 2023 – 7 –
3.4
off-peak storage water heater
storage water heater that is designed to supply hot water and configured or installed, whilst
only being supplied with electrical energy at off-peak/low-tariff periods
Note 1 to entry: The off-peak storage water heater is required to fulfil the requirements of the tapping pattern
between 7:00 h and 22:00 h without external energy supply, e.g. to enable operation at off-peak/low-tariff periods
and/or to operate in conditions of insecurity of energy supply. A product qualifies as "off-peak" if it is only energized
for a maximum of 8 consecutive hours anywhere between 22:00 h and 7:00 h during the test with the 24h load profile.
3.5
load profile
output performance (in terms of flowrates, temperatures, tapping pattern, etc.) of a storage
water heater when fulfilling its primary function under specific ambient conditions (see Table 2
and Table 3), as declared by the manufacturer
3.6
energy efficiency
ratio between the delivered energy in the domestic potable or non-potable hot water for its load
profile and the consumed electrical energy
3.7
storage volume
rated quantity of water stored in the appliance
3.8
smart control
device that automatically adapts the water heating process to individual usage conditions with
the aim of reducing energy consumption
3.9
out-of-the-box mode
standard operating condition, setting or mode set by the manufacturer at factory level, to be
active immediately after the appliance's installation, suitable for normal use by the end-user
according to the water tapping pattern for which the product has been designed and placed on
the market
3.10
closed water heater
unvented storage water heater intended to operate at the pressure of the water system, the
flow of water being controlled by one or more valves in the outlet system
3.11
cistern-fed water heater
water heater supplied from a cistern in which the flow of water is controlled by one or more
valves in the outlet system, and which is provided with a vent open to the atmosphere and so
arranged that the expanded water can return to the feed cistern
3.12
open outlet water heater
water heater in which the flow of water is controlled by a valve in the inlet pipe and so arranged
that the expanded water can overflow through the outlet pipe
3.13
vented water heater
water heater open to the atmosphere, so that under no condition of use can the pressure at the
surface of the water be other than atmospheric

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– 8 – IEC 60379:2023 © IEC 2023
3.14
cistern-type water heater
cistern-fed water heater which has a feed cistern as an integral part of the appliance
3.15
multi-tank water heater
water heater with two or more hydraulic connected containers, designed to have the possibility
to work independently in terms of working temperature and/or pressure condition
Note 1 to entry: A multi-tank product has to be defined as directly measurable if it is possible to measure the
temperature (immersed or welded sensors) of all the dome tanks without compromising the product's performances,
otherwise the product has to be classified as not directly measurable. Based on that definition for the dome tanks'
temperature measurement, the multi-tank products are defined as:
• directly measurable, or
• not directly measurable.
3.16
rated capacity
assigned water capacity of the water heater, and marked on it, by the manufacturer
3.17
standing loss per 24 h
energy-consumption of a filled water-heater, after steady-state conditions have been reached,
when connected to the electrical supply, during any 24 h duration when no water is withdrawn
3.18
rated voltage
voltage (for three phase-supply, the voltage between phases) assigned to the appliance by the
manufacturer
3.19
V
40Ref
mixed water quantity delivered at 40 °C with 65 °C storage temperature and 15 °C cold water
inlet temperature
3.20
V
40max
mixed water quantity delivered at 40 °C with maximum storage temperature setting and 15 °C
cold water inlet temperature with heating elements powered on
Note 1 to entry: Maximum rated power of the appliance.
3.21
V
40
mixed water quantity delivered at 40 °C with out-of-the-box mode temperature setting and 10 °C
cold water inlet temperature
3.22
smart control factor
SCF
factor describing the water heating energy efficiency gain due to smart control
Note 1 to entry: The value is between SCF = 0 and SCF = 1.
3.23
energy-related product
ErP
product that uses energy, or that does not use energy, but has an impact on energy consumption

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IEC 60379:2023 © IEC 2023 – 9 –
3.24
conversion coefficient
CC
factor to indicate how much primary energy is used to generate a unit of electricity
3.25
declared load profile
load profile declared by the manufacturer for the appliance
4 Symbols and units
Symbol Unit Description
η Electric energy efficiency of a storage water heater.
[%]
elecwh
Q Reference energy for the 24 h tapping pattern for the load profile of the water
ref
[kWh]
heater.

Q Electricity consumption with the relevant 24 h tapping pattern.
[kWh]
elec
Ambient temperature during the tests
θ
[°C]
amb
θ´ Mean water temperature for the determination of θ , measured at the outlet
[°C]
p p
Mean water temperature without withdraw from the tank
θ
[°C]
M
f Minimum flow rate at which hot water is contributing to the reference energy as
[l/min]
specified in Table 3.
T Water temperature at which hot water starts contributing to the reference energy as
m
[°C]
specified in Table 3
T Minimum water temperature to be achieved during water draw off as specified in
p
[°C]
Table 3
T
Set-point temperature
[°C]
set
t Reheating time for a water temperature rise of 50 K

R,50
Q Measured electricity consumption over 24 h test (step 4 of Figure 1 and Figure 2).
[kWh]
testelec
Q Useful energy content of the hot water of n draw-offs
[kWh]
H2O
Sum of quantity of hot water totally delivered during the tapping period.
full-drawing
[l]
V
water
V Measured volume delivered at the mean water temperature.
[l]
40_exp
V Mixed water quantity delivered at 40 °C.
[l]
40
V mixed water quantity delivered at 40 °C with 65 °C storage temperature and 15°C
40Ref
[l]
cold water inlet temperature
V Mixed water quantity delivered at 40 °C with maximum temperature setting and
40max
[l]
heating elements powered on
C Rated capacity of water heater (given by manufacturer)
[l]
R
C Actual capacity of water heater
[l]
act
m Actual weight of water contained inside the tank of the Water Heater
[kg]
act
m Number of tanks (containers) of the appliance
θ Mean water temperature calculated as average of the j-tank for the first thermostat
A1tanks
[°C]
cut-out
θ Mean water temperature calculated as average of j-tank for the last (n) thermostat
Antanks
[°C]
cut-out
θ Mean water temperature without withdraw of the j-tank
[°C]
Mj
θ Mean water temperature without withdraw of all the tanks
[°C]
M_mt
θ Measured water temperature after a thermostat cut-out for the j-tank
[°C]
Aij

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– 10 – IEC 60379:2023 © IEC 2023
Symbol Unit Description
θ Mean water temperature after a thermostat cut-out for the j-tank
[°C]
Aj
θ Measured water temperature after a thermostat cut-in for the j-tank
[°C]
Eij
θ Mean water temperature after a thermostat cut-in for the j-tank
[°C]
Ej
Measured temperature in the upper section of the tank
θ
[°C]
up
smart Presence or not of smart control (value shall be 0 or 1).
SCF Efficiency gain by smart control function.

5 Calculation of the electrical energy efficiency (η )
elecwh
The electrical energy efficiency (η ) of a storage water heater is the ratio between the
elecwh
delivered energy in the hot water for the tapping pattern of its
...