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Technical article · Heat pumps

Performance map to EN 14511 and EN 14825: requirements for the test bench

EN 14511 and EN 14825 specify what a test bench for heat pumps must measure. Examples are an uncertainty of ± 0.15 K on the temperature difference and a measurement time of 35 min after 30 min of steady state. With defrost, the sample interval is 10 s over up to 3 h.

Context

Performance map and rating point

A heat pump does not have one single capacity. It has a performance map. The rating plate gives one point from this map. This point applies to a specified source temperature, a specified flow temperature and a specified temperature spread. Without these 3 data, a capacity value says nothing.

The European standards specify this exactly. EN 14511 specifies test conditions and test methods. EN 14825 specifies the part load points and the calculation of the seasonal values. This article derives the requirements for the test bench from these standards. The strictest number in this family of standards does not apply to the capacity but to the temperature difference.

01

Family of standards EN 14511

EN 14511 has the common main title “Air conditioners, liquid chilling packages and heat pumps for space heating and cooling and process chillers, with electrically driven compressors”. The standard has 4 parts, all in the edition 2022 or as German version 2023[1] [2] [3] [4]:

The 4 parts of EN 14511
PartSubjectDIN editionSize
Part 1Terms and definitions2023-0820 pages[1]
Part 2Test conditions2023-0827 pages[2]
Part 3Test methods2023-1286 pages[3]
Part 4Requirements2023-0816 pages[4]

4 more standards apply:

  • EN 14825 for seasonal efficiency[5] [6]
  • EN 16147 for domestic hot water
  • EN 12102-1 for noise measurement
  • EN 15879-1 for direct exchange systems

The certification scheme Heat Pump KEYMARK gives all these standards as its normative basis. It starts with a principle that calls for tenders often do not have: only valid editions of standards apply[7].

Weight of the parts

Part 3 has 86 pages of test methods, part 4 has 16 pages of requirements. Most of the requirements for the test bench are in part 3.

02

Test conditions and rating points to EN 14511-2

EN 14511-2 defines 4 temperature applications for the sink, each by the outlet temperature[8]:

Temperature applications and sink conditions to EN 14511-2
ApplicationOutletSink in → outSpread
Low temperature35 °C30 → 35 °C5 K
Intermediate45 °C40 → 45 °C5 K
Medium55 °C47 → 55 °C8 K
High65 °C55 → 65 °C10 K

Spread and flow rate

The spread is not constant: 5 K at W35 and W45, but 8 K at W55 and 10 K at W65. At the same capacity, the flow rate thus decreases by half from W35 to W65. A test bench for all 4 applications needs a control range of at least 1 to 2 on the sink side. The control quality must stay the same over the full range.

On the source side, the standard gives the standard condition 7 °C dry bulb at 6 °C wet bulb for air. The application conditions are 2/1 °C, −7/−8 °C, −15 °C and 12/11 °C. For water, inlet 10 °C and outlet 7 °C apply. For brine, inlet 0 °C and outlet −3 °C apply[8].

The usual short notation is an industry convention, not a specification of the standard. The KEYMARK annex is an example. It gives the test points A7/W35, A20/W35, B0/W35 and W10/W35 to EN 14511-2 and E4/W35 to EN 15879-1[9]. The first letter is the source, the number after it is the source temperature. The W number is the water outlet temperature.

A2/W35 and A−7/W35

A2/W35 and A−7/W35 are not rating conditions to EN 14511-2. In that standard, they are application conditions[8], and in EN 14825 they are part load points[13]. If a customer specification gives them as rating conditions, it mixes rating conditions, application conditions and part load points.

03

Auxiliary power in the power input

Auxiliary power is one cause of data on the coefficient of performance (COP) that you cannot compare. EN 14511-3 requires that the effective power input contains the correction for fans and pumps. This applies whether the unit contains them or not[10].

Treatment of auxiliary power to EN 14511-3
CaseTreatment
integral fanspower part deducted
fans that are not integralproportional power added
integral pumpsdeducted, with efficiencies from the normative Annex F
pumps that are not integraladded

The reason: the hydraulic power of the test bench does not count. What counts is the equivalent electrical effort for the pressure drop in the unit. A technical article gives the effect of the correction on the COP as up to 0.3[11].

The defrost also has an effect on the COP. The defrost heat comes from the heating circuit, and the calculation of the COP includes the energy for it. In accordance with the quality of the defrost algorithm, this costs 0.3 to 1.0 COP points[11].

For ducted indoor units, part 3 gives minimum values of the external static pressure, in steps by rated capacity. The values go from 25 Pa up to 8 kW to 175 Pa from 147 kW. If the available static pressure is more than 2 times the minimum value, the standard requires a related adjustment of the fan speed[10].

04

Tolerances and measurement uncertainties to EN 14511-3

The standard keeps 2 quantities apart that people often mix in daily use. The first is the permitted deviation of the set test condition during the measurement. The second is the permitted measurement uncertainty of the measurement chain.

Permitted deviations in steady state to EN 14511-3, Table 5
Measured quantityarithmetic meansingle values
Liquid, inlet temperature± 0.2 K± 0.5 K
Liquid, outlet temperature± 0.3 K± 0.6 K
Liquid, volume flow or mass flow± 1 %± 2.5 %
Air, dry bulb inlet± 0.3 K± 1 K
Air, wet bulb inlet± 0.4 K± 1 K
Air flow rate± 5 %± 10 %
Voltage± 4 %± 4 %
Maximum measurement uncertainties to EN 14511-3, Table 2 (95 % coverage)
QuantityLimit
Temperature difference of the liquid± 0.15 K
Liquid flow± 1 %
Static pressure of the liquid± 1 kPa or ± 5 %
Air, dry bulb temperature± 0.2 K
Air, wet bulb temperature± 0.4 K
Air flow rate± 5 %
Electrical power± 1 %
Voltage and current± 0.5 %
Capacity with the calorimeter method± 5 %, for single-duct units ± 10 %

± 0.15 K on the temperature difference

The ± 0.15 K apply to the temperature difference, not to the absolute values. At a spread of 5 K, this is already 3 % on the capacity. With sensors that have a separate calibration each, the uncertainties of the 2 sensors go into the difference. Resistance thermometers with a calibration in pairs and in a differential circuit use the correlation of the sensors. Thus they decrease the uncertainty of the difference.

For the calculation of the capacity, EN 14511-3 contains these normative methods and annexes[10]:

Agreement of 5 % without a basis in the standard

“2 independent methods must agree within 5 %” is good test bench practice. But we did not find such a numerical requirement in EN 14511-3. The standard has an optional provision: a confirmation measurement of the capacity can use the other room or the water side[10]. Instead, the standard requires that each single method meets the uncertainty limit alone.

If you want the 5 % rule in the customer specification, write it as a requirement of your own, not as a quotation from the standard.

05

Part load and seasonal values to EN 14825

EN 14825 calculates the seasonal values SEER (Seasonal Energy Efficiency Ratio), SCOP (Seasonal Coefficient of Performance) and the related efficiency data. The methods can use measured or calculated values[6]. The standard defines 3 climate zones with 8 760 hours each[12]:

Climate zones to EN 14825
ClimateDesign temperature, heatingDesign temperature, cooling
Average−10 °C35 °C
Colder−22 °C30 °C
Warmer+2 °C40 °C
0 20 40 60 80 100 −10 −5 +0 +5 +10 +15 OUTDOOR TEMPERATURE · °C PART LOAD RATIO · % Heating load line A −7 °C · 88 % B 2 °C · 54 % C 7 °C · 35 % D 12 °C · 15 % TOL T-BIV Average climate · design temperature −10 °C · operation limit temperature max. −7 °C · bivalent temperature max. +2 °C
Fig. 1 · The 4 part load points for the average climate as a function of the outdoor temperature. A is the coldest point with the highest part load, D is the warmest point. Values from the test regulation of the European Heat Pump Association (EHPA), which gives the values of EN 14825[13].

In addition to the points A to D, EN 14825 has more points up to G for heating. These are the operation limit temperature (E), the bivalent temperature (F) and, as an option, a point at −15 °C (G)[14].

For the reference climate, the Ecodesign Regulation specifies: reference design temperature −10 °C, maximum bivalent temperature +2 °C, maximum operation limit temperature −7 °C. The European reference heating season has 4 910 hours per year[15].

A technical publication gives a methodical criticism that is important for test bench construction. At each test point, all 3 operating parameters change at the same time: source temperature, sink temperature and capacity[14]. For this reason, it is not possible to get a clean performance map from the points of EN 14825.

Performance map from separate measurements

A performance map comes only from separate measurements: change one quantity and keep the other quantities constant. The points of the standard give the values for certification, not the knowledge of the machine behaviour. The 2 tasks need the same test bench, but different test programmes.

Relation to the European regulations:

  • The Ecodesign Regulation (EU) No 813/2013 defines the seasonal space heating energy efficiency and the conversion coefficient 2.5[15].
  • The Energy Label Regulation (EU) No 811/2013 defines the efficiency classes. For low-temperature heat pumps, A+++ starts at 175 %[16].
  • The tolerance for market surveillance is 8 % for the seasonal efficiency and 2 dB for the sound power level[15].

Revision of the 2 regulations

On 2025-11-28, the European Commission started 4 parallel consultations. They apply to revised ecodesign and energy label rules for space heaters and water heaters. The time limit was 2026-01-23. Main points in the consultations:

  • label scale A to G instead of A+++ to D
  • QR codes to the European product database
  • a separate label for heat pumps with climate-friendly refrigerants
  • a third-party test

There is no date for the adoption[17].

06

Defrost and transient operation

For transient operation, the standard has the highest requirements for data acquisition.

The steady state starts when all measured quantities stay within the permitted deviations for at least 30 min without a change of the setpoints. The measurement time after this is at least 35 min. During this time, the test bench records all values at least every 30 s[10]. These are 2 separate requirements that do not overlap.

For transient operation with defrost, the standard defines 2 types of interval[10]:

The sample rates are different for the 2 intervals:

Sequence and sample rate in transient operation to EN 14511-3
StepSpecification
Preconditioningpermitted deviations met for at least 10 min · recommendation: end with a defrost cycle
Equilibrium period60 min of operation within the permitted deviations
Sample rate interval Hevery 30 s or more frequently
Sample rate interval Devery 10 s or more frequently
End of data acquisitionafter 3 h or after 3 full cycles, whichever occurs first
Averageover the integrated capacity and the time of full cycles

Average over full cycles

The standard calculates the average over full cycles, not over a fixed time window. Thus the test bench must find the limits of the cycles and keep the length of the window variable. It gives reliable enthalpy flows at an interval of 10 s, also negative capacities during the defrost.

From this comes one more requirement for the climatic chamber. It applies to the acoustic test in accordance with the EHPA regulation. For units with defrost cycles, the climatic chamber controls the air humidity at the inlet so that no defrost occurs during the measurement[13]. Thus the climatic chamber must not only humidify, but also dehumidify in a controlled way.

07

Requirements for the test bench

From the requirements in this article comes a requirement profile. Profectronics derived this profile. It does not come from the standards.

Requirements for the test bench, derived
SubsystemRequirementBasis
Sink circuitflow rate control over at least 1 to 2, control quality over the full rangespreads 5 to 10 K[8]
Temperature measurementresistance thermometers with calibration in pairs, differential circuit± 0.15 K on ΔT[10]
Flow measurementuncertainty below 1 %, calibration near the operating conditionsTable 2[10]
Climatic chambercooling, heating, humidification and dehumidification · air speed in the room below 1.5 m/s with the test specimen offAnnex A[10] [13]
Humidity measurementwet bulb with uncertainty below 0.4 KTable 2[10]
Data acquisitioninterval of 10 s, evaluation synchronous with the cycles, variable window lengthClause 4.4.4[10]
Electrical measurementpower below 1 %, voltage and current below 0.5 %Table 2[10]
Air sideflow rate measurement with uncertainty below 5 %Annex I[10]

For the air flow measurement, these method standards apply:

  • series ISO 5167 for differential pressure devices, specially part 3 for nozzles and Venturi nozzles[18] [19]
  • ISO 5801 for fan test rigs[20]
  • in the USA, ANSI/AMCA 210, identical to ASHRAE 51, in the edition 2025[21]

References in Annex I not confirmed

The accessible extract of EN 14511-3 shows only the clause titles. From this extract, we did not find an explicit reference in the normative Annex I to ISO 5167, ISO 5801 or AMCA 210.

If you write such a reference into a customer specification, examine it in the original copy of the standard.

For fans with speed control, one more requirement of ISO 5167-1 is important. The standard applies to subsonic single-phase flow and explicitly excludes pulsating flow[18].

Test and certification

There are 2 established routes to certification:

  • Heat Pump KEYMARK: covers heat pump space heaters, combination heaters and water heaters up to 400 kW. The tolerances on declared values are −8 % for the seasonal efficiency and the rated capacity and +2 dB(A) for the sound power. These are the same values as the tolerances for market surveillance in the Ecodesign Regulation[7].
  • EHPA quality label: has separate test regulations for each type of unit. For air-to-air units, it makes the calorimeter room method mandatory[13] [22].

Test bench and certification

Profectronics builds test benches for these requirements. An accredited body does the certification.

08

Change of refrigerant in accordance with Regulation (EU) 2024/573

The F-gas Regulation (EU) 2024/573 of 2024-02-07 is in force since 2024-03-11[23]. It prohibits the placement on the market of equipment with fluorinated refrigerants above specified values of the global warming potential (GWP). The prohibitions have different dates for each type and capacity. For the development of heat pumps, these dates are the most important[23] [24] [25]:

Selected prohibitions in Regulation (EU) 2024/573
TypeProhibitionfrom
Monoblock up to 12 kWGWP 150 or more2027-01-01
Monoblock above 12 up to 50 kWGWP 150 or more2027-01-01
Air-to-water split up to 12 kWGWP 150 or more2027-01-01
Air-to-air split up to 12 kWGWP 150 or more2029-01-01
Split above 12 kWGWP 750 or more2029-01-01
Split above 12 kWGWP 150 or more2033-01-01
Monoblock up to 12 kWall F-gases2032-01-01

Each prohibition in the table has an exception if the safety requirements at the site of operation require a different refrigerant. The basis is Annex IV, points 8 and 9 of Regulation (EU) 2024/573[23].

R32 and propane

In accordance with Annex I, R32 has a global warming potential of 675[23]. Thus from 2027-01-01, the prohibition applies to R32 in monoblock units up to 50 kW and in air-to-water split units up to 12 kW. For air-to-air split units up to 12 kW, this applies from 2029-01-01, for split units above 12 kW from 2033-01-01. For this reason, a test bench for these units must be suitable for refrigerants with a GWP below 150. Examples are R290 (propane) and R744 (carbon dioxide).

R290 in the test bench

ISO 817 puts propane into safety group A3, which is higher flammability. The global warming potential is 0.02, the auto-ignition temperature is 470 °C. In accordance with EN 378-2, the maximum permitted surface temperature is 370 °C. Propane is not an F-gas. Thus the obligation for leak checks in the F-gas Regulation does not apply to it[26].

For the machinery room, EN 378-3 is decisive, together with the rules for explosion protection. A technical article gives this equipment[27]:

Requirements for the machinery room with flammable refrigerants
RequirementValue
Ventilation in normal operation4 air changes per hour
Emergency ventilationat least 15 air changes per hour
Extractionnear the floor, because propane is heavier than air
Gas detection, pre-alarm20 % of the lower explosive limit
Gas detection, main alarm40 % of the lower explosive limit
Sensors, fans, uninterruptible power supplyexplosion-protected, with independent supply

For the classification of zones, EN 60079-10-1 and EN 1127-1 apply. For the qualification of personnel, EN 378-4 and ISO 22712 apply[28].

A guideline for outdoor installation gives an explicit list of the ignition sources to avoid in the protection area. The list includes electronic devices such as mobile phones and notebooks. The guideline requires that there are no ignition sources in the protection area during intended operation, not permanently and not for a short time[29].

Refrigerant charges and safety distances

The guideline does not give maximum charges for R290 in kilograms or in kilograms per cubic metre. It refers to installation conditions that the manufacturer specifies. It also does not specify fixed safety distances[29]. A number comes only from the risk assessment of the specific room.

Effects on the test bench design

A test bench for heat pumps with propane needs a zone concept with ventilation and gas detection. This concept includes gas detection with more than one stage, explosion-protected ventilation and extraction near the floor. In addition, it needs a safety chain that first ventilates and then disconnects the power if a fault occurs. These items belong in the design, not in the commissioning. They set the installation, the room height and the cable routes.

Research status August 2026

Texts of standards are not free of charge. The table values from EN 14511-2 and EN 14511-3 come from full-text copies that are available on the internet. Data on titles, editions and status come from the catalogues of the standards publishers. Profectronics builds test benches and does not certify.

Before you use the table values as a commitment, compare them with the purchased original.

09

Sources

The EU regulations and the test regulations of the certification programmes are freely accessible. They give the test points in specific terms.

  1. DIN Media · DIN EN 14511-1:2023-08 · Luftkonditionierer, Flüssigkeitskühlsätze und Wärmepumpen — Teil 1: Begriffe · 2023 · www.dinmedia.de/en/standard/din-en-14511-1/349080226 · Standard
  2. DIN Media · DIN EN 14511-2:2023-08 · Teil 2: Prüfbedingungen · 2023 · www.dinmedia.de/en/standard/din-en-14511-2/349069586 · Standard
  3. DIN Media · DIN EN 14511-3:2023-12 · Teil 3: Prüfverfahren · 2023 · www.dinmedia.de/en/standard/din-en-14511-3/349077054 · Standard
  4. DIN Media · DIN EN 14511-4:2023-08 · Teil 4: Anforderungen · 2023 · www.dinmedia.de/en/standard/din-en-14511-4/349080277 · Standard
  5. DIN Media · DIN EN 14825:2023-10 · Prüfung und Leistungsbemessung unter Teillastbedingungen, Berechnung der jahreszeitbedingten Leistung · 2023 · www.dinmedia.de/en/standard/din-en-14825/343036621 · Standard
  6. BSI / ANSI Webstore · Preview of BS EN 14825:2022 — scope and table of contents · 2022 · webstore.ansi.org/preview-pages/BSI/preview_30419055.pdf · Preview of a standard
  7. CEN-CENELEC Management Centre · Heat Pump KEYMARK — European KEYMARK Scheme for Heat Pumps, Rev. 15 · 2024-09-25 · keymark.eu/en/documents/heat-pumps/118-heat-pump-keymark-scheme-rules-v15/file · Certification scheme
  8. BS EN 14511-2:2022 · Rating conditions — Tables 5 to 10 (unofficial full-text copy) · 2022 · www.china-gauges.com/Uploads/download/649ceac0ee098.pdf · Text of a standard, unofficial
  9. CEN-CENELEC · Heat Pump KEYMARK Annex A — Testing conditions and rerating rules, Rev. 11 · 2023-12-06 · keymark.eu/en/documents/heat-pumps/104-annex-a-keymark-requirements-v11/file · Certification scheme
  10. BS EN 14511-3:2022 · Test methods — tolerances, measurement uncertainties, steady state, defrost (unofficial full-text copy) · 2022 · www.china-gauges.com/Uploads/download/649ceada5fb40.pdf · Text of a standard, unofficial
  11. B. Klein · Independent testing of heat pumps is needed for reliable COP · REHVA Journal, October 2012 · www.rehva.eu/fileadmin/hvac-dictio/05-2012/p15-18_klein.pdf · Technical article
  12. Eurovent · Eurovent 18/01-2023 · Seasonal efficiency index STER for polyvalent units · 2023-07-28 · www.eurovent.eu/wp-content/uploads/eurovent-rec-18-1-seasonal-efficiency-index-ster-1st-edition-2023-en.pdf · Industry recommendation
  13. EHPA · EHPA Testing Regulation — Testing of Air/Water Heat Pumps, V2.4a · 2021-06-07 · www.ehpa.org/wp-content/uploads/2022/07/EHPA_TestReg_AW_HP_V2.4a_20210607_.pdf · Testing regulation
  14. L. Socal · Heat pumps: lost in standards… and found · REHVA Journal 05/2021 · www.rehva.eu/rehva-journal/chapter/heat-pumps-lost-in-standards-and-found · Technical article
  15. EUR-Lex · Commission Regulation (EU) No 813/2013 implementing Directive 2009/125/EC with regard to ecodesign requirements for space heaters and combination heaters · 2013-08-02 · eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32013R0813 · Legal act
  16. EUR-Lex · Commission Delegated Regulation (EU) No 811/2013 supplementing Directive 2010/30/EU with regard to the energy labelling of space heaters, combination heaters, packages of space heater, temperature control and solar device and packages of combination heater, temperature control and solar device · 2013-02-18 · eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32013R0811 · Legal act
  17. European Commission · Ecodesign and energy labelling: Commission consults on revised rules for space and water heaters · 2025-12-01 · energy.ec.europa.eu/news/ecodesign-and-energy-labelling-commission-consults-revised-rules-space-and-water-heaters-2025-12-01_en · Notice from an authority
  18. ISO · ISO 5167-1:2022 · Measurement of fluid flow by means of pressure differential devices — Part 1 · 2022 · www.iso.org/standard/79179.html · Standard
  19. ISO · ISO 5167-3:2022 · Nozzles and Venturi nozzles · 2022 · www.iso.org/standard/84845.html · Standard
  20. ISO · ISO 5801:2017 · Fans — Performance testing using standardized airways · 2017 · www.iso.org/standard/56517.html · Standard
  21. AMCA / ASHRAE · ANSI/AMCA 210-25 (= ASHRAE 51-25) · Laboratory methods of testing fans for certified aerodynamic performance rating · 2025 · www.thenbs.com/publicationindex/documents/details?Pub=AMCA&DocId=348865 · Standard
  22. EHPA · EHPA Testing Regulation — Testing of Air/Air Heat Pumps, V1.3a · 2021-04-01 · www.ehpa.org/wp-content/uploads/2022/07/EHPA_Testreg_AA-HP_V1.3a_2021-06-22.pdf · Testing regulation
  23. EUR-Lex · Regulation (EU) 2024/573 on fluorinated greenhouse gases · 2024-02-07 · eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=OJ:L_202400573 · Legal act
  24. European Commission, DG Climate Action · Air conditioning: climate-friendly alternatives to F-gases — overview of the prohibitions · retrieved 2026 · climate.ec.europa.eu/areas-action/fluorinated-greenhouse-gases/climate-friendly-alternatives-f-gases/air-conditioning_en · Information from an authority
  25. Bundesfachschule Kälte-Klima-Technik · Die novellierte F-Gase-Verordnung — Wesentliche Änderungen für Betreiber · June 2024 · www.bfs-kaelte-klima.de/fileadmin/DATEIEN/Download/Merkblaetter/Die_novellierte_F-Gase-Verordnung-12-24.pdf · Information sheet
  26. BWP e.V. · Leitfaden Außenaufstellung von Wärmepumpen mit brennbaren Kältemitteln, Version 01.02.2024 — material data R290 · 2024 · www.waermepumpe.de/fileadmin/user_upload/BWP_LF_Kaeltemittel_WEB.pdf · Guideline
  27. H. Erös · Ausstattung von Maschinenräumen für Kälteanlagen und Wärmepumpen mit brennbaren Kältemitteln · KKA Kälte Klima Aktuell 05/2025 · www.kka-online.info/artikel/ausstattung-von-maschinenraeumen-fuer-kaelteanlagen-und-waermepumpen-mit-brennbaren-kaeltemitteln-4297296.html · Technical article
  28. Die Kälte + Klimatechnik · Brennbare Kältemittel — Gefährdungsbeurteilung in der Praxis · retrieved 2026 · www.diekaelte.de/kaeltetechnik/brennbare-kaeltemittel-gefaehrdungsbeurteilung-der-praxis-propan-anlagen-sicher · Technical article
  29. BWP e.V. · Leitfaden Außenaufstellung — protection areas and ignition sources · 2024 · www.waermepumpe.de/fileadmin/user_upload/BWP_LF_Kaeltemittel_WEB.pdf · Guideline

Data for a test bench for heat pumps

For an enquiry, please give the capacity range, the refrigerant and the type of source. Also tell us whether you plan a certification to EN 14825. From these data, we write a functional specification before the first hardware decision.

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