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CHAPTER 4. SCREENING ANALYSIS

TABLE OF CONTENTS

4.1 INTRODUCTION ........................................................................................................... 4-1

4.2 DISCUSSION OF DESIGN OPTIONS .......................................................................... 4-1

4.2.1 Screened-Out Design Options.......................................................................................... 4-1

4.2.2 Remaining Design Options.............................................................................................. 4-3

LIST OF TABLES

Table 4.2.1 Retained Design Options for Dishwashers.............................................................. 4-3
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CHAPTER 4. SCREENING ANALYSIS

4.1 INTRODUCTION

This chapter discusses the screening analysis conducted by the U.S. Department of 

Energy (DOE) of the design options identified in the market and technology assessment for 

residential dishwashers (chapter 3 of this direct final rule technical support document (TSD)). In 

the market and technology assessment, DOE presented an initial list of technologies, or design 

options that can be used to reduce energy and/or water consumption for residential dishwashers. 

The goal of the screening analysis is to identify any design options that will be eliminated from 

further consideration in the rulemaking analyses.

The candidate design options are assessed based on DOE analysis as well as inputs from 

interested parties including manufacturers, trade organizations, and energy efficiency advocates. 

Design options that are judged to be viable approaches for improving energy efficiency are 

retained as inputs to the subsequent engineering analysis. Design options which are not 

incorporated in commercial products or in working prototypes, or that fail to meet certain criteria 

as to practicability to manufacture, install and service, as to impacts on product utility or 

availability, or as to health or safety will be eliminated from consideration in accordance with 

Energy Conservation Program for Consumer Products: Procedures for Consideration of New 

or Revised Energy Conservation Standards for Consumer Products. (61 FR 36974, section 

4(a)(4) and 5(b)). The rationale for either screening out or retaining each design option is 

detailed in the following sections.

4.2 DISCUSSION OF DESIGN OPTIONS

For residential dishwashers, the screening criteria specified in section 4.1 were applied to 

the design options to either retain or eliminate each technology from the engineering analysis. 

4.2.1 Screened-Out Design Options

The technologies identified in the market and technology assessment were evaluated 

pursuant to the criteria set out in The Energy Policy and Conservation Act, as amended (EPCA 

or the Act). (42 U.S.C. 6291–6309) EPCA provides criteria for prescribing new or amended 

standards, which will achieve the maximum improvement in energy efficiency the Secretary of 

Energy determines is technologically feasible. (42 U.S.C. 6295(o)(2)(A)) It also establishes 

guidelines for determining whether a standard is economically justified. (42 U.S.C. 

6295(o)(2)(B)) In view of the EPCA requirements for determining whether a standard is 

technologically feasible and economically justified, appendix A to subpart C of Title 10 Code of 

Federal Regulations part 430 (10 CFR part 430), Procedures, Interpretations and Policies for 

Consideration of New or Revised Energy Conservation Standards for Consumer Products (the 
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“Process Rule”), sets forth procedures to guide DOE in the consideration and promulgation of 

new or revised product efficiency standards under EPCA. These procedures elaborate on the 

statutory criteria provided in 42 U.S.C. 6295 and in part eliminate problematic technologies early 

in the process of revising an energy efficiency standard. Under the guidelines, DOE eliminates 

from consideration technologies that present unacceptable problems with respect to the following 

four factors: 

(1) Technological feasibility. If it is determined that a technology has not been 

incorporated in commercial products or in working prototypes, then that technology will not be 

considered further.

(2) Practicability to manufacture, install, and service. If it is determined that mass

production of a technology in commercial products and reliable installation and servicing of the 

technology could not be achieved on the scale necessary to serve the relevant market at the time 

of the effective date of the standard, then that technology will not be considered further.

(3) Impacts on product utility to consumers. If a technology is determined to have 

significant adverse impact on the utility of the product to significant subgroups of consumers, or 

results in the unavailability of any covered product type with performance characteristics 

(including reliability), features, size, capacities, and volumes that are substantially the same as 

products generally available in the United States at the time, it will not be considered further. 

(4) Safety of technologies. If it is determined that a technology will have significant 

adverse impacts on health or safety, it will not be considered further.

The following sections detail the design options that were screened out for this 

rulemaking, and the reasons why they were eliminated.

Reduced inlet-water temperature

Reduced inlet-water temperature requires that dishwashers tap the cold water line for 

their water supply. Because most dishwashers in the United States tap the hot water line, this 

design option would require significant alteration of existing dishwasher installations in order to 

accommodate newly purchased units incorporating this design option. Therefore, DOE believes 

that it would not be practicable to install this technology on the scale necessary to serve the 

relevant market at the time of the effective date of an amended standard.

Supercritical carbon dioxide washing

Supercritical carbon dioxide washing, which uses supercritical carbon dioxide instead of 

conventional detergent and water to wash dishes, is currently being researched. Thus, DOE

believes that it would not be practicable to manufacture, install and service this technology on 

the scale necessary to serve the relevant market at the time of the effective date of an amended 

standard. Furthermore, because this technology is in the research stage, it is not yet possible to 
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assess whether it will have any adverse impacts on equipment utility to consumers or equipment 

availability, or any adverse impacts on consumers' health or safety.

Ultrasonic washing

A dishwasher using ultrasonic waves to generate a cleaning mist has been demonstrated. 

However, this model did not use ultrasonic waves in a standing fluid to clean dishes, and 

additionally relied on ion generation for further cleaning. Ultrasonic dishwashing based upon 

soiled-dish immersion in a fluid which is then excited by ultrasonic waves has not been 

demonstrated. In an immersion-based ultrasonic dishwasher, standing ultrasonic waves within 

the washing cavity and the force of bubble cavitation implosion can damage fragile dishware. 

The low water temperatures utilized by ultrasonic dishwashers may also lead to a perceived 

decrease in consumer utility, since consumers expect hot water in the dishwasher to sterilize 

dishes. Because no manufacturer currently produce ultrasonic dishwashers in the United States, 

it is impossible to assess whether this design option would have any impacts on consumers’ 

health or safety, or product availability.

4.2.2 Remaining Design Options

The following sections list the design options for each product covered by this 

rulemaking that were retained by DOE. Each of these technologies will be evaluated further in 

the subsequent engineering analysis.

For dishwashers, DOE will consider the design options shown in Table 4.2.1 for further 

analysis.

Table 4.2.1 Retained Design Options for Dishwashers

1. Condenser drying

2. Control strategies

3. Fan/jet drying 

4. Flow-through heating 

5. Improved fill control 

6. Improved food filter 

7. Improved motor efficiency

8. Improved spray-arm geometry

9. Increased insulation

10. Low-standby-loss electronic controls

11. Microprocessor controls and fuzzy logic, including adaptive or soilsensing controls

12. Modified sump geometry, with and without dual pumps

13. Variable washing pressures and flow rates