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CHAPTER 4. SCREENING ANALYSIS

TABLE OF CONTENTS

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

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

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

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

LIST OF TABLES

Table 4.2.1 Retained Design Options for Residential Clothes Washers............................... 4-4
4-1

CHAPTER 4. SCREENING ANALYSIS

4.1 INTRODUCTION

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

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

residential clothes washers (chapter 3 of this technical support document (TSD)). In the market 

and technology assessment, DOE presented an initial list of technology options that can be used 

to reduce energy consumption of residential clothes washers. The goal of the screening analysis 

is to identify any technologies that will be eliminated from further consideration in the

rulemaking analyses.

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

from stakeholders including manufacturers, trade organizations, and energy efficiency advocates. 

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

retained as inputs to the subsequent engineering analysis, and are designated as design options. 

Technology options that are not incorporated in residential clothes washer equipment or in 

working prototypes or that fail to meet certain criteria regarding practicability to manufacture, 

install and service, impacts on equipment utility or availability, or 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 (July 15, 1996). The rationale for either screening out or 

retaining each technology option is detailed in the following sections.

4.2 DISCUSSION OF TECHNOLOGY OPTIONS

For residential clothes washers, the screening criteria specified in section 4.1 were 

applied to the technology options to either retain or eliminate each technology from the 

engineering analysis. DOE derived these by reviewing the technology options for residential 

clothes washers listed in chapter 3 of the 1997 Technical Support Document for Clothes Washers

(1997 TSD). Steam washing and improved horizontal-axis-washer drum design were identified 

in the September 2005 edition of Appliance Magazine.

1 Silver ion injection was identified in the 

September 2007 edition of Appliance Magazine.2 Plastic particle cleaning was indentified in the 

September 2008 edition of Appliance Magazine.

3

4.2.1 Screened-Out Technology Options

DOE has included spray rinse and advanced 

agitator technology options based on comments to the most recent standards rulemaking for 

commercial clothes washers.

The following section details the specific technology options that were screened out prior 

to the engineering analysis, along with the rationale for elimination.
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The technologies identified in the market and technology assessment were evaluated 

pursuant to the criteria set out in EPCA. (42 U.S.C. 6291–6309) EPCA provides criteria for 

prescribing new or amended standards, which will achieve the maximum improvement in energy 

efficiency that 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 Process Rule), sets forth procedures to guide DOE in the consideration and 

promulgation of new or revised product energy conservation 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 conservation standard. Under 

the guidelines, at the outset of a rulemaking, 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 commercially available 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 commercially available 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 or product availability. If a technology is determined to 

have significant adverse impact on the utility of the equipment to significant subgroups of 

consumers, or results in the unavailability of any covered equipment type with performance 

characteristics (including reliability), features, size, capacities, and volumes that are substantially 

the same as equipment generally available in the United States at the time, it will not be 

considered further.

(4) Impacts on Health or Safety. If it is determined that a technology will have 

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

Based on these factors, DOE screened out added insulation, bubble action, electrolytic 

disassociation of water, ozonated laundering, plastic particle cleaning, and ultrasonic washing for 

the reasons that follow.
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Added insulation

As described in chapter 3, adding insulation around the outer wash tub would have an 

insignificant effect on energy efficiency. Since the wash cycle is relatively short and the thermal 

mass of the water is very high, there is very little change in water temperature from adding 

insulation. Computer simulations performed on a traditional top-loading vertical-axis clothes 

washer for a 20-minute wash cycle at 140 degrees Fahrenheit (°F) showed that adding 1 inch of 

fiberglass insulation relative to no insulation resulted in only a 1–2 °F increase in water 

temperature during parts of the wash.4 Furthermore, as water factor continues to decrease for 

residential clothes washers, the potential energy savings due to added insulation also decreases 

because of the lower quantity of hot water used during warm and hot cycles. Currently, DOE is 

unaware of any commercially available products that contain insulation around the outer wash 

tub.

Bubble action

Although bubble washing has been incorporated into commercially available residential 

clothes washers in Europe and Asia, production is extremely limited and further 

commercialization for the U.S. market would require manufacturers to develop entirely new 

platforms. Therefore, DOE does not believe that this technology would be practicable to 

manufacture, install, and service on the scale necessary to serve the relevant market at the time of 

the effective date of an amended standard.

Electrolytic disassociation of water

Electrolytic disassociation of water is in the research stage, so 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. Also, because 

this technology is in the research stage, it is not possible to 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.

Ozonated laundering

Although ozonated laundering is commercially available for residential clothes washers 

in extremely limited production in Asia, DOE believes that it would not be practicable to 

manufacture, install and service this technology on the scale necessary to serve the U.S. 

residential clothes washer market at the time of the effective date of an amended standard. Also, 

because implementation of this technology is so limited, it is not possible to 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.

Plastic particle cleaning

Plastic particle cleaning is still in the research stage, so 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. In addition, the 

requirements for the potential purchase, handling, reusing, recycling, and/or disposal of the 

plastic particles are unknown, as is cleaning performance, and therefore the impacts on consumer 

utility cannot be evaluated.
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Ultrasonic washing

Ultrasonic washing has been demonstrated in residential clothes washers, but the 

ultrasonic clothes washer did not adequately remove soil from the clothes and would therefore 

reduce consumer utility. In addition, bubble cavitations caused by standing ultrasonic waves 

could potentially damage some fragile clothing or clothing fasteners, further reducing consumer 

utility.

4.2.2 Remaining Design Options

Table 4.2.1 lists the technology options for residential clothes washers that were retained 

by DOE and subsequently designated as design options.

Table 4.2.1 Retained Design Options for Residential Clothes Washers

1. Adaptive control systems

2. Advanced agitation concepts for top-loading machines

3. Automatic water fill control

4. Direct-drive motor

5. Horizontal-axis design

6. Horizontal-axis design with recirculation

7. Hot water circulation loop

8. Improved fill control

9. Improved horizontal-axis washer drum design

10. Improved water extraction to lower remaining moisture content

11. Increased motor efficiency

12. Low standby-power electronic controls

13. Reduced thermal mass

14. Silver ion injection

15. Spray rinse or similar water-reducing rinse technology

16. Thermostatically controlled mixing valves

17. Tighter tub tolerance
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REFERENCES

 1 Appliance Magazine, September 2005. 

2 D. Simpson. 2007. “Globalizing Laundry.” Appliance Magazine, September 2007. Available 

online at: www.appliancemagazine.com/editorial.php?article=1820&zone=1&first=1

(Accessed March 11, 2010).

3 L. Bonnema. 2008. “Playing with Water,” 61st Annual Laundry Appliances Report –

Appliance Magazine, September 2008. Available online at: 

www.appliancemagazine.com/zones/consumer/04_laundry/editorial.php?article=2055&zone

=4&first=1 (Accessed March 11, 2010.)

4 Science Applications Inc. 1977. Energy Efficiency Program for Clothes Washers, Clothes 

Dryers and Dishwashers, SAI-77-839, La Jolla, CA, pp. 4–45.