Dishwasher testing

Dishwasher testing is the set of laboratory methods that measure a dishwasher's cleaning performance, drying performance, energy and water consumption, and airborne noise under controlled environmental conditions. It is governed by IEC 60436 (Electric dishwashers for household use — Methods for measuring the performance, edition 5.0, 2025) internationally, AHAM DW-2-2020 in North America (referenced by the US DOE test procedure), and the EU Ecodesign Regulation 2019/2022 plus Energy Labelling Regulation 2019/2017, which set the regulatory pass/fail lines — the Energy Efficiency Index (EEI), water, and noise caps — for the European market.

What Standards Govern Dishwasher Testing?

Dishwasher testing splits into three standards families, and the SERP — dominated by consumer "how we test" reviews that say they are "modeled after AHAM and IEC" without naming the standard numbers — rarely distinguishes them. The confusion between a performance test method (how to measure) and a regulatory gate (what limit must be met) is the main source of misleading dishwasher spec sheets.

• IEC 60436 (Electric dishwashers for household use — Methods for measuring the performance) — the international performance standard, current edition 5.0 (2025). Defines the test load (place settings and serving pieces, Annex A), the soil items and their application (egg, oatmeal, tea, margarine, minced meat, milk, etc.), the reference detergent and rinse aid, the water hardness and inlet-water temperature, and the scoring of cleaning and drying. The 2025 edition introduced combined cleaning-and-drying testing, because dishwashers can detect whether soil is present and adjust the cycle accordingly — testing the two separately let manufacturers game the cleaning test with an aggressive cycle that then failed the drying test, so the new edition combines them.
• AHAM DW-2-2020 (Household Electric Dishwashers) — the North American test method, referenced by the US Department of Energy (DOE) test procedure (10 CFR 430, Appendix C2). Defines the test load as 8 place settings plus 6 serving pieces for a standard 24-inch dishwasher, with a defined soil suite (egg, oatmeal, tomato sauce, butter/margarine, milk, tea, baby cereal, toothpaste). Cleaning is scored on a cleaning index with defined thresholds.
• EU Ecodesign Regulation 2019/2022 (in force Tier 1 from 1 March 2021, Tier 2 from 1 March 2024) and Energy Labelling Regulation 2019/2017 — the regulatory limits a dishwasher must meet to be sold in the EU. These define the Energy Efficiency Index (EEI) classes, the water-consumption caps, and the noise cap.

The fact the SERP obscures: a dishwasher's "performance" is not one number but a matrix of cleaning, drying, energy, water, and noise — each measured under a specific load, a specific soil, and a specific cycle. A spec sheet that quotes "12 place settings, A-class" without naming the standard, the cycle (almost always the eco programme for the EU label), and the inlet water conditions is unverifiable, because the same machine scores very differently on the eco programme versus the auto or heavy cycle.

How Is Cleaning Performance Tested?

Cleaning is the headline test. The IEC 60436 method (and AHAM DW-2, with differences noted):

1. Test load — a defined set of place settings and serving pieces (IEC Annex A specifies the "non-AHAM" load; AHAM DW-2 specifies 8 place settings + 6 serving pieces for a standard dishwasher). The crockery material matters — porcelain and plastic absorb heat differently and dry differently.
2. Soiling — defined soil items are applied to specific pieces in a standardized way. IEC 60436 applies, per place setting, items such as 2 g of egg (brushed on with a pastry brush), oatmeal, tea, margarine, minced meat, and milk. The soil is applied in defined quantities at defined locations so the test is repeatable.
3. Conditioning — the soiled load is held for a defined time (so the soil adheres) before the cycle starts. The dishwasher is connected to controlled inlet water at a defined temperature and hardness — water hardness changes detergent performance, so it is tightly controlled.
4. Cycle — the test cycle runs (for the EU label, the eco programme). Reference detergent and rinse aid are dosed per the standard.
5. Scoring — after the cycle (and, for the drying score, after a defined stand period with the door closed), each soiled item is inspected under defined lighting against a defined backdrop. IEC 60436 scores cleaning as a cleaning index; AHAM DW-2 uses its own cleaning index with defined thresholds.

The point both standards make, and the SERP consumer reviews miss: cleaning depends on the soil, the load pattern, the water hardness, and the cycle. Consumer reviews that smear their own food on their own plates and eyeball the result are unrepeatable — the result is specific to that food, that water, and that load arrangement. A defensible cleaning score names the standard, the soil suite, the reference detergent, the water hardness, and the cycle.

A second, less obvious test the SERP never discusses: redeposit. The CNET test in the SERP catches it with spinach on a large plate — if the filter does not retain the soil, the spinach lifts on the first spray, then redeposits on another dish later in the cycle. IEC 60436 and AHAM DW-2 control for redeposit by the location of the soil items and the order of inspection; a dishwasher that scores well on the directly-soiled item but leaves a film on the adjacent clean item has a redeposit problem, not a wash problem.

How Is Drying Performance Tested?

Drying is the second axis of performance, and it is the test that separates a premium dishwasher from a cheap one. The IEC 60436 method:

1. Cycle completion — the drying test runs as part of the cycle (combined with cleaning in the 2025 edition).
2. Stand period — after the cycle ends, the door is left closed for a defined stand time (commonly 30 minutes) to let condensation drying finish, unless the machine has an auto-door-open feature, in which case the door opens automatically and the stand-time clock starts from there.
3. Scoring — each piece is inspected for remaining moisture, scored against a defined drying scale. The result is a drying index.

Drying is governed by physics that the SERP rarely explains. The dominant drying mechanism on modern dishwashers is condensation drying: the final rinse heats the dishes to a high temperature (often 65–70 °C), then the cooler stainless-steel inner tub condenses the evaporating water onto the tank wall, from which it drains. Plastic items dry poorly because their low thermal mass and low heat conductivity leave little energy to evaporate the water film — which is why a dishwasher that dries porcelain perfectly can leave plastic containers wet. Auto-door-open drying (which lets the moist air escape by convection) and zeolite drying (which uses a desiccant that releases heat when it adsorbs water) are the two technologies that extend good drying to plastic items.

Environmental conditions dominate drying test variability — the SERP CNET review correctly identifies that high ambient humidity makes drying harder. This is why the standards specify controlled ambient conditions (temperature and humidity), and why the EU label test runs on the eco programme with the door closed for the defined stand period: the test must be repeatable across labs and seasons.

How Are Energy and Water Measured — and What Is the EEI?

Energy and water are the regulatory axis, governed by EU Regulation 2019/2022 (ecodesign) and Regulation 2019/2017 (energy label) in Europe, and by the DOE test procedure 10 CFR 430 Appendix C2 (which references AHAM DW-2) in the US. The European system is built on the Energy Efficiency Index (EEI):

• Eco programme energy consumption (EPEC) — the energy the dishwasher consumes on its eco programme for one cycle, measured per IEC 60436 with the standard load. The eco programme is mandatory because it is the cycle that best represents ordinary household use; testing on a shorter or more aggressive cycle would not represent real energy use.
• EEI calculation — the EPEC is compared to a reference value derived from the rated capacity (the number of place settings). The EEI is a dimensionless ratio; lower EEI = more efficient.
• Ecodesign gate — under Tier 2 (from 1 March 2024), a household dishwasher with ≥ 10 place settings must have EEI < 56 to be placed on the EU market. Smaller machines (≤ 7 place settings, "small" category) have a separate threshold.
• Water cap — the regulation sets a maximum water consumption per cycle, scaled by rated capacity.
• Energy classes A–G — the rescaled 2019/2017 label (no more A+/A++/A+++) places the dishwasher in a class based on its EEI, with A the most efficient.

The US DOE procedure (10 CFR 430 Appendix C2) measures energy factor (cycles per kWh) and water consumption on a defined soil load per AHAM DW-2, with a federal minimum efficiency standard that a dishwasher must meet to be sold in the US. The DOE test and the EU label are not directly comparable because the load (AHAM 8+6 vs IEC place settings), the soil suite, and the cycle (DOE permits the manufacturer-specified cycle; the EU mandates eco) differ.

How Is Noise Measured?

Noise is measured per IEC 60704-2-3 (Household and similar electrical appliances — Test code for the determination of airborne acoustical noise — Part 2-3: Particular requirements for dishwashers). The dishwasher runs in a defined test room (reverberant room per ISO 3743/ISO 3744 or hemi-anechoic chamber), at rated voltage, on the test cycle, with defined inlet water and load, and the A-weighted sound power level is reported in dB(A).

The EU ecodesign regulation requires the airborne acoustical noise emissions to be declared on the energy label, and caps noise for certain tiers. The SERP consumer reviews that use a "decibel meter app" at arm's length measure sound pressure at the operator's position, which is a different (lower) number than sound power and depends on the kitchen. Sound power — not sound pressure — is the regulatory quantity because it is intrinsic to the appliance and does not depend on the room. A defensible noise spec cites IEC 60704-2-3 and reports sound power in dB(A); modern quiet dishwashers target ≤ 44 dB(A) sound power, with premium models reaching ≈ 39–42 dB(A).

What Environmental Conditions Must Be Controlled?

The single most under-appreciated fact in dishwasher testing — and the one the SERP CNET review correctly identifies — is that dishwasher performance is dominated by environmental variables that are not part of the appliance. The IEC 60436 and AHAM DW-2 standards therefore specify and control:

• Ambient temperature and humidity — high humidity makes drying harder; the standard fixes the ambient (commonly 20–25 °C, defined humidity).
• Inlet water temperature — cold inlet versus hot inlet changes cycle energy and wash performance; the standard fixes the inlet temperature.
• Inlet water pressure and flow rate — low pressure reduces spray force and wash performance; the standard fixes these.
• Water hardness — hard water precipitates detergent and leaves spots; the standard fixes the hardness (often to a defined soft or medium value, with the rinse aid dosed to match).
• Electrical supply voltage and frequency — motor and heater performance depend on the supply.

A test result without these conditions stated is not repeatable. This is the engineering reason the SERP "we built a lab to control temperature, humidity, water temperature, water pressure, and water flow" matters: the standards require it, and a kitchen-sink test does not.

Frequently Asked Questions

What standard governs dishwasher performance testing?
IEC 60436 (Electric dishwashers for household use — Methods for measuring the performance, edition 5.0, 2025) internationally, AHAM DW-2-2020 in North America (referenced by the US DOE test procedure 10 CFR 430 Appendix C2). The 2025 edition of IEC 60436 introduced combined cleaning-and-drying testing to prevent manufacturers from gaming the two evaluations separately.

What is the difference between IEC 60436 and AHAM DW-2?
Both measure cleaning and drying, but with different loads, soils, and scoring. IEC 60436 uses the IEC place-settings load (Annex A) with soils like egg, oatmeal, tea, margarine, and minced meat, scored on an IEC cleaning index. AHAM DW-2 uses 8 place settings + 6 serving pieces with soils including egg, oatmeal, tomato sauce, butter, milk, tea, and toothpaste, scored on an AHAM cleaning index. The two systems are not directly comparable.

What is the Energy Efficiency Index (EEI)?
The EEI compares the dishwasher's energy consumption on the eco programme (EPEC) to a reference value based on its rated capacity in place settings; lower EEI = more efficient. Under EU Ecodesign Regulation 2019/2022 Tier 2 (from March 2024), dishwashers with ≥ 10 place settings must achieve EEI < 56 to be sold in the EU. The energy label (Regulation 2019/2017) places the machine in class A–G based on EEI.

Why does the EU label test on the eco programme?
Because the eco programme best represents ordinary household use and real energy consumption. Testing on a shorter or more aggressive cycle would not represent the energy a household actually uses, and would let manufacturers quote unrealistically low consumption on a cycle nobody runs.

Why do plastic items dry poorly in a dishwasher?
Modern dishwashers use condensation drying — the final rinse heats the dishes, and the cooler stainless-steel tub condenses the evaporating water. Plastic has low thermal mass and low heat conductivity, so it holds little energy to evaporate its water film. Auto-door-open drying (convection) and zeolite drying (desiccant + heat release) are the technologies that extend good drying to plastic.

Is the decibel number on a dishwasher sound pressure or sound power?
Per IEC 60704-2-3, the declared number is A-weighted sound power in dB(A) — an intrinsic property of the appliance, independent of the kitchen. Sound pressure at the operator's ear (what a phone app measures) is a lower number and depends on the room. Modern quiet dishwashers target ≤ 44 dB(A) sound power, with premium models reaching ≈ 39–42 dB(A).

Our Testing Capabilities

Beijing ZKGX Research (ISO/IEC 17025 testing laboratory) provides dishwasher testing across performance, energy, water, and noise:

• Cleaning and drying performance to IEC 60436 (edition 5.0 combined cleaning-and-drying test, IEC place-settings load and soil suite) and AHAM DW-2-2020 (8+6 load, AHAM soil suite and cleaning index).
• Energy and water — eco-programme energy consumption (EPEC), Energy Efficiency Index (EEI) and EU Ecodesign Regulation 2019/2022 conformance (Tier 2: EEI < 56 for ≥ 10 place settings; water cap per cycle), and US DOE 10 CFR 430 Appendix C2 energy factor.
• EU Energy Label to Regulation 2019/2017 (rescaled A–G classes).
• Noise to IEC 60704-2-3 — A-weighted sound power in dB(A).
• Environmental control — ambient temperature and humidity, inlet water temperature/pressure/flow, water hardness, and electrical supply, all per IEC 60436 / AHAM DW-2.

If you have a dishwasher to qualify for the EU or US market, an eco-programme EEI to verify, or a cleaning/drying claim to validate, contact our testing team to scope the applicable standards (IEC 60436 / AHAM DW-2 / EU 2019/2022 / IEC 60704), the test conditions, and the acceptance criteria.

← Previous Article Seat belt testing

Next Article → Security door testing