ISO/FDIS 5222-3

2025-08-20
ISO/TC 86/SC 6/WG 10
Secretariat: JISC
Date: 2025-10-08
Heat recovery ventilators and energy recovery ventilators — Testing
and calculating methods for performance factor —
—Part 3:
Annual sensible heating and cooling recovery performance
factorfactors of heat recovery ventilators (HRVs)
Ventilateurs récupérateurs de chaleur et ventilateurs récupérateurs d'énergie — Méthodes d'essai et de calcul
des facteurs de performances saisonnières —
Partie 3: Facteurs de performances annuelles de la récupération sensible des ventilateurs récupérateurs de
chaleur (HRV)
FDIS stage
ISO/DIS FDIS 5222-3:2025(Een)
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ii
ISO/DIS FDIS 5222-3:2025(Een)
Contents
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Tests . 3
5.1 General requirements . 3
5.2 Test conditions . 3
5.3 Test methods . 3
6 Calculations . 4
6.1 Gross sensible heating and cooling recovery effectiveness . 4
6.2 Calculation of performance factor of annual sensible heating and cooling recovery (F ) . 4
a
7 Test report . 6
Annex A (informative) The schematic diagram of HRVs’ operation . 8
Annex B (informative) Default outdoor temperature bin distribution . 12
Annex C (informative) Calculating method for annual performance factor when setting
a specific application annual load . 14
Annex D (informative) Report template . 16

iii
ISO/DIS FDIS 5222-3:2025(Een)
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
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established has the right to be represented on that committee. International organizations, governmental and
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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
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This document was prepared by Technical Committee ISO/TC 86, Refrigeration and air-conditioning, SC 6,
Testing and rating of air-conditioners and heat pumps.
A list of all parts in the ISO 5222 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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ISO/DIS FDIS 5222-3:2025(Een)
Heat recovery ventilators and energy recovery ventilators — Testing
and calculating methods for performance factor —
Part 3:
Annual sensible heating and cooling recovery performance
factorfactors of heat recovery ventilators (HRVs)
1 Scope
This document specifies the testing and calculating methods for annual sensible heating and cooling recovery
performance factorfactors of heat recovery ventilators (HRVs) covered by ISO 16494-1.
This document also specifies the test conditions and the corresponding test procedures for determining the
annual sensible heating and cooling recovery seasonal performance factorfactors of HRVs. It is intended for
use only in marking, and comparison and certification purposes. The procedures of this document can be used
for other temperature conditions.
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 16494--1:2022, Heat recovery ventilators and energy recovery ventilators — Method of test for performance
— Part 1: Development of metrics for evaluation of energy related performance
ISO 5222--1:20232025, Heat recovery ventilators and energy recovery ventilators — Testing and calculating
methods for seasonal performance factor — Part 1: Sensible heating recovery seasonal performance factors of
heat recovery ventilators (HRV)
ISO 5222--2:2025, Heat recovery ventilators and energy recovery ventilators -— Testing and calculating
methods for seasonal performance factor -— Part 2: Sensible cooling recovery seasonal performance factors of
heat recovery ventilators (HRV)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1649116494-1 and the following
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/
3.1 3.1
annual sensible heating and cooling recovery seasonal performance factor of HRVs
F
a
ratio of the annual amount of sensible heating and cooling recovered together with the power value of moving
air to the annual amount of electricity input of heat recovery ventilators (HRVs,), under the rating conditions
and annual outdoor temperature bins selected from this standarddocument
ISO/DIS FDIS 5222-3:2025(Een)
4 Symbols
Symbol Description Unit
Esh capacity of seasonal sensible heating recovery Wh
E capacity of seasonal sensible cooling recovery Wh
sc
E capacity of ventilation only period Wh
v
Ea capacity of annual sensible heating and cooling recovery Wh
annual performance factor of sensible heating and cooling recovery seasonal
Fa Wh/Wh
performance factor
nj bin hours which the outdoor air bin temperature occurs h
n number of temperature bins –
power input to the HRVs to operate the fans at outdoor air bin temperature t for
j
Pin,no,t,j W
ventilation only, for HRVs without bypass ventilation function
power input to the HRVs to operate the fans at outdoor air bin temperature tj for
Pin,by,t,j W
ventilation only, for HRVs with bypass ventilation function
Pin,E,sh power input of seasonal sensible heating recovery Wh
P power input of seasonal sensible cooling recovery Wh
in,E,sc
P power input of ventilation only Wh
in,E,v
Pin,E,a annual sensible heating and cooling recovery power input Wh
annual fan power input under condition ofwith AC turnsturned off and keeping
ΔPin,E,hc Wh
ventilation kept on
ventilation air cooling load with recovery or ventilation air heating load with
Qvwr W
recovery
ventilation air cooling load without recovery or ventilation air heating load without
Qv W
recovery
Qig cooling load generated from internal gain and, solar gain, etc. W
Q2,net net supply mass flow rate W
Q amount saved by recovery function W
s
T lowest outdoor temperature during cooling season ℃°C
oac
To,h temperature defined in ISO 16494-1:2022, Table 2 as T5/T6/T7 ℃°C
TBHB building heating balance temperature ℃°C
T bypass outdoor temperature ℃°C
b
dry bulb temperature under ISO 16494-1 standard testingtest conditions
T ℃°C
o,c
(T1/T2/T3/T4/T8)
T building heat balance temperature ℃°C
BCB
TF outdoor air bin temperature at which the frost occurs ℃°C
ϕsh,t,j sensible heating recovery capacity of the HRVs at outdoor air bin temperature tj W
ϕsc,t,j sensible cooling recovery capacity of the HRVs at outdoor air bin temperature tj W
ISO/DIS FDIS 5222-3:2025(Een)
5 Tests
5.1 General requirements
The tests conditions used and, the accuracy and uncertainties of the instruments used shall conform to ISO
16494-1, ISO 5222-1 and ISO 5222-2.
5.2 Test conditions
For the purposes of test and calculation, there are eight standard test conditions T1/T2/T3/T4/T5/T6/T7/T8
defined in ISO 16494-1:2022, Table 1 and Table 2. The HRVs shall be tested atunder one of the eight test
conditions, which should be selected to most closely represent the outdoor temperature bin distribution in
the region as described in Annexes BAnnex B and CC. .
5.3 Test methods
5.3.1 General
For higher annual energy performance, HRVs can be designed with air flow bypass function and integrating
fan speed control or airflow control devices, which can result in a reduction in fan power input according to
different outdoor temperature conditions.
5.3.2 5.3.2 Energy saving stage limit temperature
See Annex AAnnex A for a schematic diagram of the operation stages under the application temperature bin
for assessing the energy saving ability of HRVs.
5.3.3 Sensible heating and cooling recovery performance test
5.3.3.1 Sensible heating recovery performance test
SensibleThe sensible heating recovery performance test shall conform to ISO 5222-1:20232025, 5.3.3.
5.3.3.2 Sensible cooling recovery performance test
SensibleThe sensible cooling recovery performance test shall conform to ISO 5222-2:2025, 5.3.3.
5.3.4 Determination of bypass outdoor temperature
The determination of bypass outdoor temperature shall conform to ISO 5222-1:20232025, 5.3.4 and
ISO 5222-2:2025, 5.3.4.
5.3.5 Measurement of power input of heat recovery ventilator with bypass ventilation function
The measurement of power input of heat recovery ventilator with bypass ventilation function shall conform
to ISO 5222-1:20232025, 5.3.5 and ISO 5222-2:2025, 5.3.5.
5.3.6 Measurement of power input of heat recovery ventilator with no bypass ventilation function
The measurement of power input of heat recovery ventilator with no bypass ventilation function shall
conform to ISO 5222-1:20232025, 5.3.5.6 and ISO 5222-2:2025, 5.3.6.
ISO/DIS FDIS 5222-3:2025(Een)
6 Calculations
6.1 Gross sensible heating and cooling recovery effectiveness
The gross sensible heating and cooling recovery effectiveness of HRVs at rated test conditions are described
in ISO 16494-1:2022, 9.5.
6.2 Calculation of performance factor of annual sensible heating and cooling recovery (F )
a
6.2.1 Characteristics of annual sensible recovery capacity against outdoor temperature
a) a) The characteristics of sensible heating recovery capacity ϕ (W) against outdoor
sh,t,j
temperature shall conform to ISO 5222-1:20232025, 6.3.2.
b) b) The characteristics of sensible cooling recovery capacity ϕ (W) against outdoor temperature
sc,t,j
shall conform to ISO 5222-2:2025, 6.2.2.
NOTE The annual sensible heating and cooling recovery capacity of HRVs at outdoor temperature t change with the
j
outdoor temperature, as shown in Figure A.1Figure A.1.
6.2.2 Power input characteristics of annual sensible heating and cooling recovery against outdoor
temperature
a) a) The characteristics of power input for sensible heating against outdoor temperature shall
c
...