ISO 5222-3:2026

International
Standard
ISO 5222-3
First edition
Heat recovery ventilators and
2026-01
energy recovery ventilators —
Testing and calculating methods for
performance factor —
Part 3:
Annual sensible heating and cooling
recovery performance factors of
heat recovery ventilators (HRVs)
Ventilateurs récupérateurs de chaleur et ventilateurs
récupérateurs d'énergie — Méthodes d'essai et de calcul du
facteur de performance —
Partie 3: Facteurs de performance annuelle de la récupération
de chaleur et de refroidissement sensibles des ventilateurs
récupérateurs de chaleur (HRVs)
Reference number
© ISO 2026
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Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Tests . 2
5.1 General requirements .2
5.2 Test conditions .2
5.3 Test methods .3
5.3.1 General .3
5.3.2 Energy saving stage limit temperature .3
5.3.3 Sensible heating and cooling recovery performance test .3
5.3.4 Determination of bypass outdoor temperature .3
5.3.5 Measurement of power input of heat recovery ventilator with bypass ventilation
function.3
5.3.6 Measurement of power input of heat recovery ventilator with no bypass
ventilation function .3
6 Calculations . 3
6.1 Gross sensible heating and cooling recovery effectiveness .3
6.2 Calculation of performance factor of annual sensible heating and cooling recovery (F ) .3
a
6.2.1 Characteristics of annual sensible recovery capacity against outdoor
temperature .3
6.2.2 Power input characteristics of annual sensible heating and cooling recovery
against outdoor temperature . .4
6.2.3 Outdoor temperature bin distribution for annual heating and cooling .4
6.2.4 Calculation of annual sensible heating and cooling recovery capacity (E ) .4
a
6.2.5 Calculation of annual sensible heating and cooling recovery power input (P ) .5
in,E,a
6.2.6 Calculation of performance factor for annual sensible heating and cooling
recovery (F ) .5
a
7 Test report . 5
Annex A (informative) The schematic diagram of HRVs’ operation . 7
Annex B (informative) Default outdoor temperature bin distribution .10
Annex C (informative) Calculating method for annual performance factor when setting
a specific application annual load .11
Annex D (informative) Report template .13

iii
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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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 document 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).
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Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
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.

iv
International Standard ISO 5222-3:2026(en)
Heat recovery ventilators and energy recovery ventilators —
Testing and calculating methods for performance factor —
Part 3:
Annual sensible heating and cooling recovery performance
factors of heat recovery ventilators (HRVs)
1 Scope
This document specifies the testing and calculating methods for annual sensible heating and cooling
recovery performance factors 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 factors of HRVs. It is intended for use in
marking and comparison. 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 5222-1:2025, 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 16494-1 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
annual sensible heating and cooling recovery seasonal performance factor
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 document

4 Symbols
Symbol Description Unit
E capacity of seasonal sensible heating recovery Wh
sh
E capacity of seasonal sensible cooling recovery Wh
sc
E capacity of ventilation only period Wh
v
E capacity of annual sensible heating and cooling recovery Wh
a
F annual sensible heating and cooling recovery seasonal performance factor Wh/Wh
a
n bin hours which the outdoor air bin temperature occurs h
j
n number of temperature bins –
power input to the HRVs to operate the fans at outdoor air bin temperature t for
j
P W
in,no,t,j
ventilation only, for HRVs without bypass ventilation function
power input to the HRVs to operate the fans at outdoor air bin temperature t for
j
P W
in,by,t,j
ventilation only, for HRVs with bypass ventilation function
P power input of seasonal sensible heating recovery Wh
in,E,sh
P power input of seasonal sensible cooling recovery Wh
in,E,sc
P power input of ventilation only Wh
in,E,v
P annual sensible heating and cooling recovery power input Wh
in,E,a
ΔP annual fan power with AC turned off and ventilation kept on Wh
in,E,hc
Q ventilation air cooling or heating load with recovery W
vwr
Q ventilation air cooling or heating load without recovery W
v
Q cooling load generated from internal gain, solar gain, etc. W
ig
Q net supply mass flow rate W
2,net
Q amount saved by recovery function W
s
T lowest outdoor temperature during cooling season °C
oac
T temperature defined in ISO 16494-1:2022, Table 2 as T5/T6/T7 °C
o,h
T building heating balance temperature °C
BHB
T bypass outdoor temperature °C
b
dry bulb temperature under ISO 16494-1 standard test conditions (T1/T2/T3/T4/
T °C
o,c
T8)
T building heat balance temperature °C
BCB
T outdoor air bin temperature at which the frost occurs °C
F
ϕ sensible heating recovery capacity of the HRVs at outdoor air bin temperature t W
sh,t,j j
ϕ sensible cooling recovery capacity of the HRVs at outdoor air bin temperature t W
sc,t,j j
5 Tests
5.1 General requirements
The tests conditions used, 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 a
...