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Department for Business, Energy and Industrial Strategy

Undercounter Dishwashers

1.1           Scope 

Undercounter dishwashers are used in the operation of professional foodservice outlets to clean items that are either used to prepare or consume food, such as cooking ware, dishes, cutlery and glasses. The choice of the type and number of ware-washing machine(s) is largely dictated by the number of customers an operation serves per day – undercounter dishwashers are a common appliance used in lower volume operations and are designed to be installed under food preparation workspaces or under counters in the front bar area. The main difference between a professional and domestic undercounter dishwasher is the ability of a professional machine to perform multiple, short duration cleaning cycles. A typical cleaning cycle for a professional undercounter dishwasher lasts a duration of 1,5-3 minutes.  

1.2           Definitions 

Undercounter dishwashers are stationary rack machines, with a front door which opens to the internal wash compartment. The front surface door of the machine is pulled down to open the cleaning compartment where soiled dishes, cutlery and other ware can be placed inside on either fixed or removable racks. The front surface is then pulled up to close the machine’s compartment.  

Undercounter dishwashers come in similar (height x width x depth) dimensions and during operation undergo wash and rinse sequences in each cycle. The internal wash compartment of undercounter dishwashers is populated with a series of wash arms with water spraying nozzles, designed to guide the fluid in different directions, with the objective of covering all the areas of the soiled ware to be cleaned with water and the cleaning chemicals aids or wash detergents.  

These machines have high temperature sanitising processes and may have an internal or external booster heater to elevate the incoming rinse water to required temperature for the final rinse. The final rinse water is repurposed for subsequent wash cycles thereafter until the wash tank is drained and eventually replenished prior to the next series of cycles.   

Additional features found in some undercounter dishwashers may include an integrated water treatment which can be used to soften the water hardness, while some high temperature machines, may include heat recovery systems which can recover the remaining heat from the previous cycle to preheat the incoming water for the next cleaning cycle. 

Glasswashers, manufactured for the sole purpose of cleaning glassware and are otherwise referred to as dedicated glasswashers as per their manufacturer specified intended use, are not eligible under the scope of these criteria. 

Undercounter dishwashers are available in a range of different designs and efficiencies. The Energy Technology List (ETL) Scheme aims to encourage the purchase of higher efficiency products. 

To be eligible for inclusion on the ETL, products shall meet the requirements as set out below.  

1.3           Requirements  

1.3.1       Eligibility requirements 

To be eligible, products shall: 

  • Align with the product definition in section 1.2.
  • Have a single water tank.
  • Have an appropriate Conformity Assessment mark.

1.3.2       Performance requirements 

Eligible products shall meet the performance criteria set out in Table 1.1. 

Table 1.1    Performance requirements for high temperature undercounter dishwashers 

Aspect Units Threshold 
Energy Energy consumption per cycle (EC) (kWh/cycle) 0.4 kWh
Water consumption per cycle (VC) (L/cycle) 3.4 L
Power ready-to-use mode (PU) (kW) 0.4 kW
Cleaning Cleaning performance (Xclean) (%) 90%
Hygiene / Sanitation Pass / Fail Pass

Applicants shall report the following performance parameters for each model, which will be published on the ETL Product Search

  • Declaration of the programme in which the model was tested under.
  • Declaration of the rinse temperature (°C) during testing (referred to as the manufacturer’s setting of boiler temperature in Table 2 of BS EN IEC 63136: 2019).
  • Average programme time (TPR).
  • Average cycle time (TC).

1.4           Measurement and Calculations 

1.4.1       Measurement standards 

The following standards shall be used to determine product performance. 

Energy consumption 

  • BS EN IEC 63136: 2019[1] Electric dishwashers for commercial use. Test methods for measuring the performance. 

Cleaning performance  

  • BS EN IEC 63136: 2019 Electric dishwashers for commercial use. Test methods for measuring the performance. 

Hygiene/sanitisation (either/or) 

  • prEN 17735: 2021[2] Commercial dishwashing machines - Hygiene requirement and testing. 
  • NSF/ANSI 3-2019[3] Commercial ware-washing Equipment – Performance requirement for high temperature machine testing with a minimum of 3,600 heat unit equivalents (HUE) at the surface of dishes. 

1.4.2       Test requirements 

The specific test parameters and data recorded from the model testing shall be reported based on the BS EN IEC 63136:2019 section 8, data to be reported requirements as outlined below.  

  • The laboratory data shall be reported in accordance with Table 1 of the test standard. 
  • The dishwasher data shall be reported in accordance with Table 2 of the test standard. 
  • The test measured data shall be reported in accordance with Table 3 of the test standard. 
  • For the cleaning performance evaluation, the data shall be recorded in accordance with Table 4 of the test standard.  

1.4.3       Rounding 

There shall be no benefit gained from rounding of the energy performance results. For example, a model’s energy consumption per cycle of 0.41 kWh would be considered ineligible under these criteria.  

1.5           Verification for ETL Listing  

Any of the following testing routes may be used to demonstrate the conformity of products against the requirements: 

  • In-house testing – Self-tested and verified or cross-checked by an independent body. 
  • Witnessed testing. 
  • Independent testing. 
  • Representative testing (see clause 1.5.1 below).    

Further information regarding the first three routes can be found in the ETL Testing Framework.

1.5.1       Representative testing  

Where applications are being made for two or more models that are variants of the same basic design, test data may be submitted for a single ‘representative model’ provided that all variants:  

  • Operate at the same water temperature. 
  • Have the same wash cycle energy and water consumption. 
  • Have the same dimensions (e.g., height x width x depth). 
  • Operate on the same cleaning programmes (e.g., no. of cycles per minute). 
  • Use the same power in ready-to-use mode (kW). 

It should be noted that:       

  • If a manufacturer voluntarily removes the representative model from the ETL then other products linked with that representative model may or may not be permitted to remain on the ETL.  
  • If any product submitted under these representative model rules is later found not to meet the performance criteria when independently tested, then all products based on the same representative model will be removed from the ETL. 

1.6           Conformity testing 

Products listed on the ETL may be subject to the scheme’s conformity testing programme in order to ensure listed models continue to meet the ETL requirements.  

1.7           Review  

1.7.1       Indicative review date  

This specification is scheduled to be reviewed during the 2023/24 review cycle. 

1.7.2       Illustrative future direction of the requirements   

The next technical review will consider amending the energy efficiency thresholds for undercounter dishwashers in light of the performance data collected during the intervening period.  

The next technical review will also consider if an additional test and measurement standard has been published covering either energy, cleaning, hygiene/sanitisation or rinse performance measurements for this technology, as well as the potential inclusion of dedicated glasswashers.


[1] BS EN IEC: British Standard, European Norm, International Electrotechnical Commission

[2] prEN: Draft European Standard

[3] NSF/ANSI: National Sanitation Foundation/American National Standards Institute