5-i CHAPTER 5

. ENGINEERING ANALYSIS

TABLE OF CO NTENTS

5.1 INTRODUCTION

................................ ................................ ................................ ........... 5

- 1

5.2 PRODUCT CLASSES ANAL YZED

................................ ................................ .............. 5

- 1

5. 3 EFFICIENCY LEVELS

................................ ................................ ................................ ... 5

- 2

5.3.1 Baseline Units

................................ ................................ ................................ .................. 5

- 3

5.3.2 Incremental Efficiency Levels

................................ ................................ ......................... 5

- 3

5.3.2.1 Standard Product Class

................................ ................................ .................. 5

- 3

5.3.2.2 Compact Product Class

................................ ................................ .................. 5

- 4

5.4 METHODOLOGY OVERVIEW

................................ ................................ .................... 5

- 5

5.4.1 AHAM Data Request

................................ ................................ ................................ ....... 5

- 5

5.4.2 Manufacturer Interviews

................................ ................................ ................................ .. 5

- 5

5.4.3 Product Teardowns

................................ ................................ ................................ .......... 5

- 6

5.4.3.1 Selection of Units

................................ ................................ ........................... 5

- 6

5.4.3.2 Generation of Bill of Materials

................................ ................................ ...... 5

- 6

5.4.3.3 Cost Structure of the Spreadsheet Models

................................ ..................... 5

- 7

5.4.3.4 Cost Model and Definitions

................................ ................................ ........... 5

- 8

5.4.3.5 Cost Model Assumptions

................................ ................................ ............... 5

- 9

5.4.4 Review of Previous Technical Support Documents and Models

................................ ..... 5

- 9

5.4.5 Product Testing

................................ ................................ ................................ .............. 5

- 10

5.5 ANALYSIS AND RESULTS

................................ ................................ ........................ 5

- 10

5.5.1 AHAM Data

................................ ................................ ................................ ................... 5

- 10

5.5.2 Product Teardowns

................................ ................................ ................................ ........ 5

- 11

5.5.2.1 Baseline Construction: Standard Dishwasher

................................ .............. 5

- 12

5.5.2.2 Baseline Construction: Compact Dishwasher

................................ .............. 5

- 14

5.5.2.3 Construction at Higher Efficiency Levels

................................ .................... 5

- 15

5.5.3 Cost

- Efficiency Curves

................................ ................................ ................................ .. 5

- 21

5.5.3.1 Standard Dishwashers

................................ ................................ .................. 5

- 21

5.5.3.2 Compact Dishwashers

................................ ................................ .................. 5

- 21

5.5.4 Manufacturer Interviews

................................ ................................ ................................ 5

- 22

5.5.4.1 Design Features of Current Baseline Products

................................ ............ 5

- 23

5.5.4.2 Proposed Incremental Efficiency Levels

................................ ..................... 5

- 23

5.5.4.3 Design Options Required to Meet Each Efficiency Level

........................... 5

- 23

5.5.4.4 Impact on Consumer Utility

................................ ................................ ......... 5

- 23

5.5.4.1 Installation and Repair Costs as a Function of Efficiency

........................... 5

- 24

LIST OF TABLES

Table 5.3.1 Standard Dishwasher Efficiency Levels, Based on Annual Energy Use and Water Consumption

................................ ................................ ............................. 5

- 4 Table 5.3.2 Efficiency Levels for Compact Residential Dishwashers

................................ ......... 5

- 55-ii Table 5.4.1 Major Manufactu ring Processes

................................ ................................ ............... 5

- 8 Table 5.5.1 AHAM Residential Dishwasher Shipments Data Submittal

................................ .. 5

- 10
Table 5.5.2 AHAM Residential Dishwasher Shipment

- Weighted Average Efficiency

Data Submittal

................................ ................................ ................................ ... 5

- 11
Table 5.5.3 AHAM Residential Dishwasher Market Share Efficiency Data Submittal

............ 5

- 11
Table 5.5.4 Standard Residential Dishwasher Features

................................ ............................. 5

- 12
Table 5.5.5 Baseline Standard Dishwasher Production Cost Distribution

................................ 5

- 13
Table 5.5.6 Baseline Standard Dishwasher Materials Cost Distribution

................................ ... 5

- 14
Table 5.5.7 Baseline Co mpact Dishwasher Production Cost Distribution

................................ 5

- 15 Table 5.5.8 Baseline Compact Dishwasher Materials Cost Distribution

................................ ... 5

- 15 Table 5.5.9 Standard Dishwasher Incremental Manufacturing Costs

................................ ........ 5

- 21 Table 5.5.10 Compact Dishwasher Increme ntal Manufacturing Costs

................................ ..... 5

- 22

LIST OF FIGURE S Figure 5.4.1 Manufacturing Cost Assessment Stages

................................ ................................ .. 5

- 7 Figure 5.5.1 Baseline Standard Dishwasher Production Cost Distribution

............................... 5

- 13 Figure 5.5.2 Baseline Standard Dishwasher Materials Cost Distribution

................................ . 5

- 14 Figure 5.5.3 Baseline Compact Dishwasher Production Cost Distribution

............................... 5

- 15 Figure 5.5.4 Baseline Compac t Dishwasher Materials Cost Distribution

................................ . 5

- 155-1 CHAPTER 5. ENGINEERING ANALYSIS

5.1 INTRODUCTION

After conducting the screening analysis, the U.S. Department of Energy (DOE) performed an engineering analysis based on the remaining design options

. The engineering analysis consists of estimating the energy and water consumption and costs of residential

dishwashers at various levels of increased efficiency

. This section provides an overview of the engineering analysis (section 5.1 ), discusses pro duct classes (section 5.2 ), establishes baseline and incremental efficiency levels (section 5.3 ), explains the methodology used during data gathering ( section 5.4 ) and discusses the analysis and results (section 5.5 )

.

The primary inputs to the engineering analysis are baseline information from the market and technology assessment ( c hapter 3 of th is direct final rule technical support document ( TSD ) ) and technology options from the screening analysis ( c hapter 4)

. Additional inputs include cost and energy efficiency data, which DOE received from the Association of Home Ap pliance Manufacturers ( AHAM ) and qualified and supplemented through teardown analysis and

manufacturer interviews

. The primary output of the engineering analysis is a set of cost

efficiency curves

. In the subsequent markups analysis ( c hapter 6 ), DOE dete rmined customer ( i.e. product purchaser) prices by applying distribution markups, sales tax and contractor markups

. After applying these markups, the cost

- efficiency curves serve as the input to the building energy

- use and end

- use load characterization ( c hapter 7 )

, and the life

- cycle cost (LCC) and payback period (PBP) analyses ( c hapter 8)

.

DOE typically structures its engineering analysis around one of three methodologies

. These are: (1) the design

- option approach, which calculates the incremental costs of adding specific design options to a baseline model; (2) the efficiency

- level approach, which calculates the relative costs of achieving increases in energy efficiency leve ls, without regard to the particular design options used to achieve such increases; and/or (3) the reverse

- engineering or

cost

- assessment approach, which involves a “bottom

- up” manufacturing cost assessment based

on a detailed bill of materials (BOM) deriv ed from teardowns of the product or equipment being analyzed

. Deciding which methodology to use for the engineering analysis depends on the covered product , the design options under study, and any historical data that DOE can draw on.

5.2 PRODUCT CLASSES AN ALYZED

DOE separated residential dishwashers into two product classes

. In general, the criteria for separation into different classes are (1) type of energy used (natural gas or electricity), and (2) capacity or other performance

- related features such as those that provide utility to the5-2 consumer, or others deemed appropriate by the Secretary that would justify the establishment of a separate energy conservation standard

. (42 U.S.C. 6295 (q) )

For di shwashers, the size of the unit significantly impacts the energy consumed. In other words, standard

- size dishwashers with relatively greater water consumption have significantly greater energy use than compact units. Because standard dishwashers offer en hanced consumer utility over compact units ( i.e. , the ability to wash more dishes), DOE has separate d residential

dish washers into the following two product classes , based on the size of the dishwasher (as specified in American National Standards Institute ( ANSI ) /AHAM Standard DW

- 1

- 1992

, Dishwashers ):

 Compact, capacity less than 8 place settings plus 6 serving pieces; and

 Standard, capacity equal to or greater than 8 place settings plus 6 serving pieces.

For this engineering analysis, DOE analyzed product s from both the standard and
compact product class es

.

5.3 EFFICIENCY LEVELS

For residential dish washers

, energy conservation standard levels are c urrently defined by

two factors

– annual energy use and water consumption. T he annual energy use calculation

accounts for m achine electrical energy consumption , e xternal water heating energy consumption

, and s tandby energy consumption. W ater consumption is a direct measurement of the water used during the energy test for non

- soil

- sensing dishwashers

, and a weighted average of the water used for the three different test cycles (with heavy, medium, and light soil loads) for soil

- sensing

dishwashers.

Section 310 of the Energy Independence and Security Act of 2007 (EISA 2007), Pub. L.

110

- 140, amended section 325 of the Energy Policy and Conservation Act (EPCA) of 1975, Pub.

L. 94

- 163, (42 U.S.C. 6291

– 6309) to require that the test procedure for dishwashers be amended to include measurement of standby mode and off mode energy use, taking into co nsideration the

most current versions of Standards 62301 and 62087 of the International Electrotechnical

Commission (IEC). a EPCA, as amended by EISA 2007, also required that any final rule establishing or revising a standard for a covered product, adopted after July 1, 2010, shall incorporate standby mode and off mode energy use into a single amended or new standard, if

feasible. If not feasible, the Secretary shall prescribe within the final rule a separate standard for standby mode and off mode energy c onsumption

. ( 42 U.S.C. 6295(gg))

a The most current version is IEC Standard 62301, “Household electrical appliances

– Measurement of standby power”, Second Edition, 2011. IEC Standard 62087, “Methods of measurement for the power consumption of audio, video, and related equipment,” Sec ond Edition, 2008

- 2010, is not applicable to this rulemaking. IEC standards may be purchased online at www.iec.ch

.5-3 The current DOE dishwasher test procedure in 10 CFR 430, subpart B, appendix C already includes a measure of standby mode energy use, although it is not based on the methods

in IEC Standard 62301. DOE is conducting a rule making to amend the test procedure for

dish washers to provide for measurement of standby mode and off mode energy use based on IEC

Standard 62301

. DOE does not expect , however, that the amended test procedure will result in significantly different measured annual energy uses for residential dishwashers. As a result,

DOE believes that th e analyse s described in the direct final rule TSD using efficiency ratings based on the existing test procedure will remain valid after the test procedure amendments take

effect

.

5.3.1 Baseline Units

DOE selected a baseline unit to represent the basic characteristics of equipment for
dishwashers

. Typically, a baseline unit is a unit that just meets current energy conservation

stand ards and provides basic consumer utility. DOE used the baseline unit in the engineering analysis and the LCC and PBP analys e s

. To determine energy savings and changes in price, DOE compared each higher energy efficiency design option with the baseline un it

.

EPCA, as amended by EISA 2007

, establishe d the following energy and water

conservation standards for dishwashers manufactured on or after January 1, 201 0 (42 U.S.C. 6295(g)(10)) , which DOE has incorporated into its analysis as the baseline efficiency levels :

**•** Standard dishwashers

– 355 kilowatt

- hours per year ( k W h/year ) and 6.5 gallons per cycle ; and

**•** Compact dishwashers

– 260 kWh/year and 4.5 gallons per cycle.

5.3.2 Incremental Efficiency Levels

5.3.2.1 Standard Product Class

DOE analyzed several efficiency leve ls for standard dishwashers

, and obtained
incremental cost data at each of these levels

. Table 5.3

. 1 includes the analyzed efficiency le vels

and the reference source of each level for the standard product class

.5-4 Table 5.3

. 1 Standard Dishwasher Efficiency Levels , Based on Annual Energy Use and Water Consumption

Level Efficiency Level Reference Source Efficiency Level

Annual Energy Use ( kWh / year ) Water Consumption ( gallons/ cycle )

Baseline DOE Standard 355 6.5

EL 1 ENERGY STAR (current) 324 5.8

EL 2 CEE Tier 1/Consensus Agreement 307 5.0

EL 3 CEE Tier 2 / future ENERGY STAR (effective January 20, 2012) 295 4.25

EL 4 Gap Fill a 234 3.8

EL 5 Maximum Available a 180 1.6 a) Source: ENERGY STAR

- qualified dishwashers as of July 13, 2011

.

DOE analyzed five efficiency levels beyond the baseline

. These levels were based on the

current and future ENERGY STAR levels, the Consortium for Energy Efficiency (CEE)

R esidential Dishwasher Initiative efficiency tiers, and the maximum level that is currently commercially available (which DOE used as a proxy for max

- tech) as determined from data contained within the California Energy Commission (CEC) and ENERGY STAR product

database s. DOE added a gap

- fill level to span the large difference in efficiency between the CEE
Tier 2 and maximum available level. Efficiency Level 2 also corresponds to the standard dishwasher efficiency level agreed upon in a consensus agreement jointly subm itted to DOE by

AHAM and the American Council for an Energy

- Efficient Economy ( ACEEE ), also on behalf of multiple manufacturers, efficiency advocates, and consumer groups

. (See chapter 3 of the direct

final rule TSD for further description of this “Consens us Agreement.”)

EPCA mandates that DOE analyze the maximum technologically feasible (max

- tech) model, based on a m inimum annual energy use and a minimum water consumption for

residential dishwashers

. The two variables are related to a certain extent ( v ia external and

internal water heating energy consumption ) and DOE evaluates the relative importance of each metric in setting the energy conservation standards. It is not certain that a residential dish washer

with the lowest possible annual energy use will also achieve the lowest possible water consumption

. Similarly, a dishwasher with the lowest water consumption may not achieve the

lowest annual energy use

. However

, for residential dishwashers currently available on the

market

, the units achieving the lo west annual energy use also achieve the lowest water consumption , and therefore repres ent the max

- tech level

.

5.3.2.2 Compact Product Class

The Consensus Agreement includes a proposed energy conservation standard for the compact product class

. EPCA , as amended

, allows DOE to issue a final rule establishing an energy conservation standard on receipt of a statement submitted jointly by interested persons that are fairly representative of relevant points of view (including representatives of

manufacturers of covered products, States, and efficiency advocates) that contains recommendations with respect to an energy conservation standard that are in accordance with the5-5 provisions of 42 U.S.C. 6295(o). The standards proposed in the Consensus Agreement are based

on annu al energy use and water consumption

.

Table 5.3

. 2 below shows the current DOE standard for the compact product class, the efficiency level proposed in the Consensus Agreement , and the max

- tech level. DOE only analyzed two efficiency levels beyond the baseline because the number of compact dishwasher models commercially available is too small to warrant any gap

- fill levels.

Table 5.3

. 2 Efficiency Levels for Compact Residential Dishwashers

Level Efficiency Level Description Annual Energy

Use (kWh/year) Water Consumption

(gal/cycle )

Baseline DOE Standard 260 4.5

EL 1 Cons ensus Agreement / future ENERGY STAR (effective January 20, 2012) 222 3.5

EL 2 Maximum Available a 154 2.1
a) Source: ENERGY STAR

- quali fied dishwashers as of July 13 , 2011.

5.4 METHODOLOGY OVERVIEW

DOE relied on multiple source s of information for this engineering analysis

. These
sources include an AHAM data submittal, manufacturer interviews, product teardowns, a review of TSDs from previous rulemakings, and internal product testing.

5.4.1 AHAM Data Request

In support of this rulemaking effort, DOE requested data from AHAM for residential
dishwashers

. The data represent shipments, shipment

- weighted average efficiency, and market share efficiency data

. A discussion of the data provided by AHAM is included in section 5.5.1

. The data submittal did not include manufacturing cost information.

5.4.2 Manufacturer Interviews

DOE understands that there is variability among manufacturers in baseline units, design strategies , and cost structures

. To be tter understand and explain these variances, DOE conducted

manufacturer interviews

. These confidential interviews provided a deeper understanding of the various combinations of technologies used to increase residential dish washer efficiency, and their associated manufacturing costs

. Sample questions asked during the interviews are contained

in a ppendix 12

- A

.

During the interviews, DOE also gathered information about the capital expenditures required to increase the efficiency of the baseline units to various efficiency levels ( i.e.

, conversion capital expenditures by efficiency or energy

- use level)

. The interviews provided5-6 information about the size and the nature of the capital investments

. DOE also requested information about the depreciation method used to expense the conversion capital. The manufacturer impact analysis in c hapter 12 of the direct final rule TSD includes a discussion of this information obtained during manufacturer interviews.

5.4.3 Product Teardowns

Other than obtaining detailed manufacturing costs directly from a ma nufacturer, the most accurate method for determining the production cost of a product is to disassemble representative

unit s piece

- by

- piece and estimate the material

, labor , and overhead cost s associated with each
component using a process commonly called a physical teardown. A supplementary method, called a catalog teardown, uses published manufacturer catalogs and supplementary component data to estimate the major physical differences between a product that has been physically

disassembled and another si milar product

. DOE performed physical teardown analysis on both standard and compact dish washers

. The teardown methodology is exp lained in the following

sections

.

5.4.3.1 Selection of Units

DOE generally adopt s the following criteria for selecting units for teardown analysis:

**•** T he selected products should span the full range of efficiency levels for each product class under consideration;

**•** W ithin each product class, the selected products should

, if possible, come from the same
manufacturer and belong to the same product platform ;

**•** T he selected products should , if possible, come from manufacturer s with large market share s in that product class, although the highest efficiency products are chosen irrespective of manufacturer; and

**•** T he selected products should have non

- efficiency

- related features that are the same as, or similar to, features of other products in the same class and at the same efficiency level.

5.4.3.2 Generation of Bill of Materials

The end result of each t eardown is a structured BOM , which describe s each product part and its relationship to the other parts, in the estimated order of assembly

. The BOMs describe each fabrication and assembly operation in detail, including the type of value

— added equipment

ne eded ( e.g. , stamping presses, injection molding machines, spot

- welders, etc.) and the estimated cycle times associated with each conversion step

. The result is a thorough and explicit model of the production process.

Materials in the BOM are divided between raw materials that require conversion steps to be made ready for assembly, while purchased parts are typically delivered ready for installation. The classification into raw materials or purchased parts is based on DOE’s previous industry experienc e, recent information in trade publications, and discussions with original equipment5-7 manufacturers (OEMs). For purchased parts, the purchase price is based on volume

- variable price quotations and detailed discussions with suppliers.

For parts fabricated in

- house

, the prices of the underlying “raw” metals ( e.g. , tube, sheet metal) are estimated on the basis of 5

- year averages to smooth out spikes in demand

. Other “raw” materials such as plastic resins, insulation materials, etc. are estimated on a current

- market

basis. The cost s of raw materials are based on manufacturer interviews, quotes from suppliers, secondary research, and by subscriptions to publications including the American Metals Market b

5.4.3.3 Cost Structure of the Spreadsheet Models (AMM)

. Past price quotes are indexed using applicable B ureau of Labor Statistics producer price index tables as well as AMM monthly data

.

The manufacturing cost assessment methodology used is a detailed, component

- focused technique for rigorously calculating the manufa cturing cost of a product (direct materials, direct

labor and some overhead costs). Figure 5.4

. 1 shows the three major steps in generating the manufacturing cost.

Figure 5.4

. 1 Manufacturing Cost Assessment Stages

The first step in the man ufacturing cost assessment was the creation of a complete and structured BOM from the disassembly of the units selected for teardown

. The units were dismantled, and each part was characterized according to weight, manufacturing processes used, dimensions, material

, and quantity. The BOM incorporates all materials, components, and fasteners with estimates of raw material costs and purchased part costs. Assumptions on the sourcing of parts and in

- house fabrication were based on industry experience, informa tion in trade publications

, and discussions with manufacturers. Interviews and plant visits were conducted with manufacturers to ensure accuracy on methodology and pricing.

Following the development of a detailed BOM, the major manufacturing processes wer e identified and developed for the spreadsheet model. Some of t hese processes are listed in Table

5.4

. 1

.

b For information on American Metals Market, please visit: www.amm.com

.5-8 Table 5.4

. 1 Major Manufacturing Processes

Fabrication Finishing Assembly/Joining Quality Control Fixturing Stamping/Pressing Brake Forming Cutting and Shearing Insulating

Turret Punch Tube Forming Enameling Washing Powder Coating

De

- burring Polishing Refrigerant Charging Adhesive Bonding Spot Welding Seam Welding Packaging Inspecting & Testing

Fabrication process cycle times for each part made in

- house we re estimated and entered

into the BOM. Based on estimated assembly and fabrication time requirements, the labor content of each appliance could be estimated. For this analysi s, $ 24.00 per ho ur was used as the average fully

- burdened labor rate based on typical annual wages and benefits of indus try employees.

Cycle requirements for fabrication steps were similarly aggregated by fabrication machine type while accounting for dedicated vs. non

- dedicated machinery and/or change

- over times (die swaps in a press, for example). Once the cost estimate for each teardown unit was finalized, a detailed summary was prepared for relevant components, subassemblies and

processes. The BOM thus details all aspects of unit costs : material, labor, and overhead.

Design options used in units subject to teardown are noted in the summary sheet of each

cost model and are cost

- estimated individually. Thus, various implementations of design options can be accommodated, ranging from assemblies that are entirely purchased to units that are made

ent irely from raw materials. Hybrid assemblies, consisting of purchased parts and parts made on

site are thus also accommodated.

5.4.3.4 Cost Model and Definitions

The cost model is based on production activities and divides factory costs into the following categor ies:

**•** Materials: Purchased parts ( i.e.

, motors

, valves

, etc .), raw materials, ( i.e. , cold rolled steel, copper tube, etc .), and indirect materials that are used for processing and

fabrication.

**•** Labor: Fabrication, assembly, indirect, and supervisor labor. Fabrication and assembly labor cost are burdened with benefits and supervisory costs.

**•** Overhead: Equipment, tooling, and building depreciation, as well as utilities, equipment and tooling maintenance, insurance, and property taxes.

Cost Definitions

Because there are many different accounting systems and methods to monitor costs, DOE

defined the above terms as follows:5-9 **•** Direct material: Purchased parts (out

- sourced) plus manufactured parts (made in

- house from raw materials).

**•** Indirect material: Materia l used during manufacturing ( e.g. , welding rods, adhesives).

**•** Fabrication labor: Labor associated with in

- house piece manufacturing.

**•** Assembly labor: Labor associated with final assembly.

**•** Supervisory labor: Labor associated with fabrication and assembly basi s. Assigned on a span basis (x number of employees per supervisor) that depends on the industry.

**•** Indirect labor: Labor costs that scale with fabrication and assembly labor. These included the cost of technicians, manufacturing engineering support, stocki ng, etc . that are proportional to all other labor.

**•** Equipment depreciation: Money allocated to pay for initial equipment installation and replacement as the production equipment is amortized. All depreciation is assigned in a

linear fashion and affected e quipment life depends on the type of equipment

.

**•** Tooling depreciation: Cost for initial tooling (including non

- recurring engineering and debugging of the tools) and tooling replacement as it wears out or is rendered obsolete.

**•** Building depreciation: Money allocated to pay for the building space and the conveyors that feed and/or make up the assembly line.

**•** Utilities: Electricity, gas, telephones, etc.

**•** Maintenance: Annual money spent on maintaining tooling and equipment.

**•** Insurance: Appropriated as a function of unit cost.

**•** Property Tax: Appropriated as a function of unit cost.

5.4.3.5 Cost Model Assumptions

As discussed in the previous section, assumptions about manufacturer practices and cost structure played an important role in estimating the final product cost. I n converting physical information about the product into cost information, DOE reconstructed manufacturing processes for each component using internal expertise and knowledge of the methods used by the industry.

Site visits allowed DOE to confirm its cost model assumptions through direct observation of the manufacturing plant, as well as through manufacturer interviews, reviews of current Bureau of Labor Statistics data, etc.

5.4.4 Review of Previous Technical Support Documents and Models

DOE reviewed previous rulemaking TSDs to assess their applicability to the current standard setting p rocess for residential dishw ashers. These previous rulemaking TSDs served as a source for design options and energy consumption analysis, in addition to other sources.5-10 5.4.5 Product Testing

Much of the analysis in this chapter relies on data from publicly available sources such as
the CEC and ENERGY STAR databases. However, DOE also conducted its own limited performance testing according to the DOE test procedure for the following pu rposes:

**•** Verify performance trends that are apparent in the publicly available data ;

**•** Develop a better understanding of the design options and product features currently available on the market ; and

**•** Develop a better understanding of the operational character istics of residential
dish washers

.

5.5 ANALYSIS AND RESULTS

5.5.1 AHAM Data

To support the DOE rulemaking, AHAM collected shipment and efficiency data from its member companies

. For reasons of product availability and number of manufacturers, AHAM did not provide disaggregated data for compact dish washers. Table 5.5.1 compile s unit shipment

data for residential dish washers from 2000 to 20 10

. The data is split between portable and built

in units, however these distinctions do not correspond to the compact and standard product

classes.

Table 5.5

. 1 AHAM Residential Dishw asher Shipments Data Submittal

Year Total Shipments Portable Built

- In

2000 5,827,678 164,425 5,663,253

2001 5,627,373 149,372 5,478,001

2002 6,206,792 158,131 6,048,661

2003 6,428,351 148,092 6,280,259

2004 7,105,511 152,968 6,952,543

2005 7,424,196 133,204 7,290,992

2006 7,251,504 129,777 7,121,727

2007 6,976,830 110,213 6,866,617

2008 5,995,124 91,693 5,903,431

2009 5,403,652 70,278 5,333,374

2010 5,710,406 65,544 5,644,862

Table 5.5.2 reproduces AHAM's data submittal for the shipment

- weighted average efficiency levels for all residential dish washer shipments

. The data show the shipment

- weighted energy use in kWh per cycle as well as the calculated annual energy use for the total industry

. The calculated annual energy use values assume 215 cycles per year, but do not account for annual standby energy consumption as in the current DOE test procedure, and therefore likely slightly underestimate the actual representative shipment

- weighted average annual energy use

.5-11 Table 5.5

. 2 AHAM Residential Dishw asher Shipment

- Weighted Ave rage Efficiency Data

Submittal

Year Shipment

- Weighted Average Energy Use (kWh/cycle) Calculated Shipment

- Weighted Average Annual Energy Use (kWh/year)

2000 2.00 430

2001 1.92 413

2002 1.84 396

2003 1.83 393

2004 1.68 361

2005 1.67 359

2006 1.63 350

2007 1.53 329

2008 1.52 327

2009 1.45 312

2010 1.37 295 a) Based on 215 cycles per year. Does not account for annual standby energy consumption.

AHAM provided market share efficiency data for residential dishw ashers for 2008 to
20 10 , as shown in Table 5.5

. 3

. For some entries, market share data are provided combining multiple efficiency levels. In these cases, AHAM has combined the efficiency levels to mainta in manufacturer confidentiality.

Table 5.5

. 3 AHAM Residential Dishw asher Market Share Efficiency Data Submittal
Efficiency

Level Annual Energy Use Range (kWh/year) Average Water Consumption (gallons/cycle, 2009) Market Share (percent) c

2008 2009 2010

Baseline 325

– 355 4.84 51.2% 37.3% 3.8%

EL1 308

– 324 4.38 27.2% 39.7% 51.7%

EL2 296

– 307 5.09 7.1% 8.6% 21.5%

EL3 235

– 295 4.7 5.3% a 10.8% b 22.8% b

EL4 181

– 234 2.7 n/a n/a n/a

EL5 ≤ 180 2.63 0.0% n/a n/a

a) Includes levels 3 and 4. b) Includes levels 3, 4, and 5. c) Numbers may not add exactly to 100%

5.5.2 Product Teardown s

DOE conducted a market survey of residential dish washer models and their associ ated

features

. After reviewing the model data, DOE selected 12 standard and 3 compact dish washers

for t eardowns . These selections were based on the proposed efficiency levels and the range of product efficiencies and features available on the market. DOE conducted the d ishwasher teardowns to identify design features and corresponding manufacturing costs that are associated with successively higher efficiency levels. Table 5.5

. 4 lis ts features typical of the selected units in the standard product class at the corresponding analyzed efficiency levels.5-12 Table 5.5

. 4 Standard Residential Dishwasher Features

Feature Standard Residential Dishwasher Features by Efficiency Level

Baseline EL 1 EL 2 EL 3 EL 4 EL 5 Annual Energy

Use (kW h /year) 355 324 307 295 234 180

Water Consumption (gallons/cycle) 6.5 5.8 5.0 4.25 3.8 1.6

Control Type Electro

mechanical Electronic Electronic Electronic Electronic Electronic

Soil Sensing No No Yes Yes Yes Yes Dry ing Type Heat Dry Heat Dry Heat Dry Condensation Condensation Condensation

Insulation/Tub Type Non

- Insulated

Plastic Non

- Insulated

Plastic Insulated

Plastic Insulated

Plastic Insulated

Plastic Ins ulated

Plastic

Heater Type Tubular, In

tub Tubular, In

- tub Tubular, In

tub In

- line Flow

through In

- line Flow

through Integrated in Pump Temperature Sensing Temperature
Switch Temperature
Switch Temperature
Switch Temperature

Sensor Temperature

Sensor Temperature

Sensor

Water Fill

Control Timed Fill Timed Fill Timed Fill Flow Meter Flow Meter Flow Meter

Water Filter Large Particle

Plastic Filter + Disposal Large Particle + Fine (SS) Large
Particle + Fine (SS) Large
Particle + Fine (SS) Large
Particle + Fine (SS) Large Particle + Fine (SS)

Spray System 1

- Arm
w/T ower Multiple Arms,

No Diverter Multiple Arms, No
Diverter Multiple Arms, No
Diverter Multiple Arms, w/

Diverter Multiple Arms,

w/ Diverter

Power Supply N/A Linear Switch

Mode Switch Mode Switch Mode Switch Mode

Pump Motor Technology 1

- Speed 1

- Speed Variable Speed Variable Speed Variable Speed Variable Speed

Drain Pump No Separate

D rain P ump Yes Yes Yes Yes Yes

Hydraulic System Optimization None None Partial

– Water Lines Complete

– Sump and

Water Lines Complete

– Sump and

Water Lines Complete

– Sump and

Water Lines

Control Strategies N/A N/A Longer Cycles Longer Cycles Lower
Wash/Rinse Temperatures Lower
Wash/Rinse Temperatures

5.5.2.1 Baseline Construction: Standard Dishw asher

The baseline standard dish washer is equipped with electromechanical controls that allow the user to select specific cycle settings. Th is include s a switch for selecting the power dry option and a rotary dial to initiate and set the cycle duration

. Because the electromechanical controls are used, the standby mode and off mode power consumption are zero.

The wash tub is made of plastic using an injection mold ing process , with no added insulation. Inside the tub are upper and lower racks for loading the dishware. The baseline dishwasher has only one spray arm at the base of the tub, with a spray tower that extends up into5-13 the tub when water circulates . A tubular resistance heater , a c oarse plastic filter, and an overflow

float switch also sit at the base of the tub.

The water system includes a one

- speed motor that drives a pump to circulate water within the tub and to drain water out of the unit, depending on the position of a soleno id valve in the water lines. Because the baseline unit has only a coarse plastic filter, the motor also drives a disposal to break down food particles that would make it into the water lines. The baseline unit

uses timed fills to control the volume of wa ter entering the unit, with no flow meter or fill level pressure switch

.

Based on product teardowns, DOE developed the following baseline production and

materials cost distributions for a standard dish washer

. Table 5.5

. 5 and Figure 5.5

. 1 show the baseline production cost distributions; and Table 5.5

. 6 and Figure 5.5

. 2 show the baseline

materials cost distribution. Depending on the manufacturer and the production volume, the depreciation costs may vary from those show n in the figures, which assume a “green

- field” site.

Table 5.5

. 5 Baseline Standard Dishwa sher Production Cost Distribution

Cost Category Total

Cost ($2010)

Figure 5.5

. 1 Baseline Standard Dishw asher Production Cost

Distribution Raw Materials $42.63

Purchased Parts $77.29

Assy Labor Cost $12.21

Fab Labor Cost $12.26

Supervision Cost $1.27

Indirect Labor Cost $8.50

Equipment Dep. Cost $5.08

Tooling Dep. Costs $10.16

Building Dep. Cost $5.33

Indirect Process Cost $3.17

Maintenance $ 5.09

Utility Cost $2.58

Property Tax $3.90

Insurance $1.52

Total $ 190.985-14 Table 5.5

. 6 Baseline Standard Dishw asher Materials Cost Distribution

Sub

- Assembly Total

Materials

Cost ($2010)

Figure 5.5

. 2 Baseline Standard Dishw asher Materials

Cost Distribution Packaging $ 10.99

Final Assy $17.56

Shell $15.50

Water System $40.74

Racks $13.83

Controls $14.84

Wiring Harness $6.05

Vent $0.41

Total $ 119.92

5.5.2.2 Baseline Construction: Compact Dishwasher

The baseline compact dishwasher is a countertop unit that incorporates many design features used to minimize energy and water consumption. The electronic controls on the baseline model allow for more complex control strategies compared to a unit with

electromechanical controls. The electr onic controls employ a linear power supply, with an associated standby and off mode power consumption of 2.3 watts. The unit includes a flow meter and pressure switch for fill control, and a temperature sensor to control the heater operation.

The tub o n the baseline unit is made of stainless steel with bitumen insulation on the

exterior to improve the unit’s noise performance. The tub only includes one dish rack and one spray arm because multiple racks cannot fit into the more compact volume. It uses a flow

through water heater integrated into the sump as opposed to a tubular in

- tub heating element

, which leaves more volume in the tub available for loading dishes

.

The baseline compact dishwasher has more effective water filtering than the baseline

standard unit. It includes a coarse stainless steel filter, and a finer stainless steel mesh filter to

catch smaller food particles. No disposal is necessary because large food particles do not pass through these filters into the water system.

Based on product teardowns, DOE developed the following baseline production and

mate rials cost distributions for a compact dishwasher. Table 5.5

. 7 and F igure 5.5

. 3 show the baseline production cost distributions; and Table 5.5

. 8 and Figure 5.5

. 4 show the baseline materials cost distribution. Depending on the manufacturer and the production volume, the depreciation costs may vary from those shown in the figures, which assume a “green

- field” site.5-15 Table 5.5

. 7 Baseline Compact Dishwasher Production Cost Distribution

Cost Category Total

Cost ($2010)

Figure 5.5

. 3 Baseline Compact Dishw asher Production Cost

Distribution Raw Materials $50.48

Purchased Parts $78.59

Assy Labor Cost $12.19

Fab Labor Cost $7.32

Supervision Cost $1.01

Indirect Labor Cost $6.77

Equipment Dep. Cost $3.79

Tooling Dep. Costs $6.61

Building Dep. Cost $4.96

Indirect Process Cost $2.17

Maintenance $3.80

Utility Cost $2.76

Property Tax $3.79

Insurance $1.47

Total $ 185.71

Table 5.5

. 8 Baseline Compact Dishwasher Materials Cost Distribution

Sub

- Assembly Total

Materials

Cost ($2010)

Figure 5.5

. 4 Baseline Compact Dishw asher Materials

Cost Distribution Packaging $ 5.90

Final Assy $11.90

Shell $23.07

Water System $41.30

Racks $5.71

Controls $34.39

Wiring Harness $6.80

Total $ 129.07

5.5.2.3 Construction at Higher Efficiency Levels

Based on the design options retained from the screening analysis (see chapter 4 of the

direct final rule TSD), the reverse

- engineering analyses, and discussions with manufacturers,5-16 summarized in section 5.5.4 , DOE developed manufacturing costs associated with various design features necessary to achieve higher efficiencies.

The following are the design changes DOE believes manufacturers would typically use to

meet each efficiency level

. These configurations were subsequently modeled to obtain incremental manufacturing cost estimates.

Standard Dishw ashers

Efficiency Level 1

Based on characteristics of units selected for teardown and based on discussions with

manuf acturers, DOE research suggests that efficiency level ( EL ) 1 is typically achieved in

standard dish washers through the following incremental changes to the baseline unit described in

section 5.5.2.1 :

1. Electronic Controls Through its observations and discussions with manufacturers, DOE believes that in moving from the baseline level to EL 1, manufa cturers would likely replace electromech anical

controls with electronic controls

. This would allo w for m ore sophisticated control during the cycle , which could result in more precise timing and feedback control , eliminating excess energy and water consumption. The electronic controls at EL 1 w ould likely employ a linear power supply. The standby mode and off mode power consumption associated with the electronic

controls are 2.3 watts.

2. Multiple Spray Arms At EL 1, the single spray arm and spray tower of the baseline unit are likely replaced by
two separate spray arms

– one dedicated to each rack of dishes. This helps reduce water consumption by more accurately directing the water to the dishes. Less water is needed while still ensuring the dishes are washed effectively.

3. Im proved Water Filters

The coarse water filter in the baseline dishwasher allows food to pass through to the

macerator. After the food is broken down, pieces still make their way through the water system, so the lines and spray arms must allow the food particles to pass through to prevent clogs. At EL 1, manufacturers would likely add a finer food filter using perforated s tainless steel. By trapping smaller food particles and eliminating the food disposer, the typical unit at EL 1 can use smaller

tube diameters and thinner spray arms without clogging, decreasing the total volume of the water system.

4. Separate Drain Pump

Th e baseline un it uses a single pump to circulate water within the dishwasher and to drain

water out of the unit. At EL 1, manufacturers would likely include a separate pump and motor dedicated to draining water from the unit. Circulating water within the unit requires a stronger motor than for draining the water, so the EL 1 unit avoids the excess energy consumption associated with using the circulating motor to pump water out of the unit.5-17 Efficiency Level 2
Through research and discussions with manufact urers, DOE believes that manufacturers

would likely improve on the other design options used for EL 1, and would incorporate certain

additional features to reach EL 2 :

1. Soil Sens ing A dishwasher meeting EL 2 likely incorporates more advanced controls, incl uding a turbidity sensor. The turbidity sensor monitors the clarity of the water passing through the sump, and adjusts the wash cycle accordingly. A s a result, the dishwasher can adjust to use less water and energy for less

- soiled dish loads.

2. 3

- Phase Va riable

- Speed Motor
The EL 2 dish washer would likely feature a variable

- speed motor to drive the circulation

pump

. This allows the dishwasher to adjust the speed water is pumped throughout the water system depending on the point during the cycle. Using the most energy

- intensive pump operation only when needed eliminates excess energy consumption for portions of the wash cycle using less aggressive circulation.

3. Hydraulic System Optimization At EL 2, manufacturers would likely further decrease the c apacity of the water system by optimizing the water lines and spray arms. This includes both decreasing the volume of the fill lines and spray arms, and moving the main water feed line to the tub interior, thereby decreasing its length.

4. Control Strategie s As manufacturers decrease energy and water consumption, they increase certain other wash cycle parameters to maintain washing performance. At EL 2, manufacturers would likely increase the duration of the cycle to compensate for decreased water use. Run ning the dishwasher for a longer period of time has a minor energy penalty, but it is outweighed by the corresponding decrease in water heating and machine electrical consumption.

5. Tub Insulation With the high temperatures generated during a dishwashing cy cle, the unit can lose a significant amount of heat through the plastic tub walls. At EL 2, manufacturers would li kely add a cotton jacket to help keep the heat within the tub. This differs from units with stainless

steel tubs and bitumen insulation ; for those units, the bitumen is used to aid in noise performance, and actually has a corresponding energy penalty due to the added thermal mass.

6. Switch Mode Power Supply At EL 2, manufacturers would likely switch from a linear power supply to a switch mode

p ower supply. This decreases the amount of energy consumed by the unit when it is in standby

mode or off mode. The standby mode and off mode power consumption associated with the electronic controls using a switch mode power supply are 1.7 watts.

Efficie ncy Level 35-18 A dish washer at EL 3 is likely to em ploy many of the same design features as one at EL

2. The major incremental changes associated with the decreased energy and water consumption

at this level are:

1. Flow

- Through Water Heater Baseline through EL 2 dishwashers likely use a tubular, in

- tub water heater. This requires a certain volume of standing water within the tub in addition to the volume of the sump

and water lines. At EL 3, manufacturers would likely use a flow

- through water heater located below the tub next to the sump assembly. This allows for effective water heating with a smaller

volume of standing water.

2. Condensation Drying Without the typical tubular in

- tub water heater from the previous levels, manufacturers would likely eliminate the heated drying option. Heated drying uses the resistance heater to warm the air in the tub and evaporate the water off the dishes. Condensat ion drying uses a higher temperature final rinse to raise the temperature of the dishes, and then uses a fan to introduce cooler air from the kitchen to cool the wash tub walls where the evaporated water

condenses. The condensation drying strategy uses le ss energy compared to the heated drying

method.

3. Hydraulic System Optimization At EL 3, manufacturers would likely further decrease the total volume of the water
system. In addition to using smaller supply lines and spray arms, EL 3 would incorporate a

re designed sump with a smaller internal volume.

4. Temperature Sensor

B aseline through EL 2 dishwashers typically include temperature switches to control the

water heater. At EL 3, manufacturers would likely switch to a temperature sensor to allow for

closed

- loop control , rather than timed heating with a maximum cutoff point determined by the

switch. Better temperature control results in less energy use associated with internal water heating.

5. Flow Meter At EL 3, manufacturers would likely switch from timed f ill control to using a water flow

meter. A flow meter with an electronic controller allows a dishwasher to dose water very precisely, even at varying supply pressures. This reduces the excess energy and water consumption associated with overfilling the d ishwasher, and helps prevent poor wash performance caused by under

- filling

.

Efficiency Level 4
At EL 4, DOE believes manufacturers would likely make four incremental changes to the

unit described for EL 3 :5-19 1. Water Diverter Assembly

DOE believes m anufa cturers would likely incorporate a water diverter valve at EL 4.
The diverter directs the flow of water from the circulating pump to either the top or bottom spray arm depending on its position. This allows the dishes in both the top and bottom racks to receive

the same spray volume, while maintaining a smaller volume of water in the sump and water

lines. This technology may also correspond to a further increase in cycle duration as both racks

ar e not washed simultaneously.

2. Control Strategies To further decrease energy consumption at EL 4, DOE believes manufacturers would

decrease wash and /or rinse temperatures. This decreases the amount of energy consumed for water heating (both internal and ex ternal) , but has the potential to hurt wash performance.

3. Improved Filters At EL 4, manufacturers would likely further improve the water filtering syste m. For EL 1 through EL 3, the finest filters use perforated stainless steel. The fine filter at EL 4 wo uld likely switch to a woven stainless steel cloth, which is capable of trapping even smaller food particles. This further decreases the potential for clogging in the water system, leading to decreased water consumption.

4. Humidity Sensor

In addition to th e condensation drying system at EL 3, manufacturers would likely add a humidity sensor at EL 4. This sensor detects when the humidity in the tub reaches a certain level indicating the dishes are dry, and shuts off the fan drawing cool air into the tub. T his eliminates

the small amount of excess energy consumption associated with running the fan after the air in

the tub is sufficiently dry.

Efficiency Level 5
To reach the minimum energy and water consumption levels for standard dishwashers currently avai lable, manufacturers would likely make the following two changes:

1. In

- Pump Heater At EL 5, manufacturers would likely replace the flow

- through water heater with a design that incorporates the heating element into the circulation pump. This design change e liminates the water volume necessary to fill the water lines to the flow

- through heater, and to fill the heater

itself. This design change also requires a further redesign of the sump assembly.

2. Remove Vent Fan
DOE believes that dish washers at EL 5 would likely also eliminate the air circulation fan

. This saves the small amount of energy associated with running the fan after the final rinse cycle

, but also decreases the drying performance of the unit

.5-20 Compact Dishw ashers

Starting with the baseline compact dishwasher described in section 5.5.2.2 , DOE believes manufacturers would incorporate incremental changes to reach EL 1 and EL 2. As des cribed in

section 5.3.2.2 , DOE only analyzed two efficiency levels beyond the baseline due to the small number of compact dishwasher models available on the market

.

Efficiency Level 1
The baseline compact dishwasher already incorporates many of the design options used to decrease energy and water consumption in standard dishwashers. As a result, the baseline unit performs significantly better than the DOE standar d, and nearly reaches the energy and water consumption levels specified for EL 1. To improve the unit’s performance to meet the EL 1 levels, DOE believes manufacturers would likely alter the control system to use slightly less water, and possibly to incre ase the cycle duration.

Efficiency Level 2

The max

- tech dishwasher available on the market is a dish drawer instead of a countertop unit. The configuration of dish drawers makes them significantly more expensive to manufacture compared to a countertop u nit. However, DOE believes the design features used in

the max

- tech unit could be incorporated into a countertop platform. The features DOE expects
manufacturers to use to reach EL 2 are listed below:

1. Permanent Magnet Motor
DOE believes manufacturers wo uld switch to a permanent magnet motor to reach EL 2. With this type of motor, the pump impeller is attached directly to the rotor, so no drive system is required. Additionally, manufacturers would likely use this motor for both circulating water during the wash or rinse cycles and for pumping water out of the unit, depending on which direction the rotor spins.

2. Heater Incorporated into Base of Tub

DOE observed that the max

- tech compact dishwasher incorporates the internal water

heater into the base of th e tub. This requires a lower volume of w ater sitting in the bottom of the

tub than a tubular in

- tub water heater, and eliminates the volume required to fill a flow

- through

water heater.

3. Reduced Sump Volume Combined with the two design options listed abov e, DOE expects manufacturers would decrease the sump volume to the extent that it would only house the pump impeller. Because

there is no heater integrated in the sump, and only one pump impeller housing, the volume of water required to fill the sump and water lines is much less than for the sump configuration on the baseline and EL 1 units

.

4. Switch Mode Power Supply At EL 2, manufacturers would likely switch from a linear power supply to a switch mode power supply. This decreases the amount of energy consumed by the unit when it is in standby5-21 mode or off mode. The standby mode and off mode power consumption associated with the electronic controls using a switch mode power supply are 1.7 watts.

5.5.3 Cost

- Efficiency Cur ves

Based upon product teardowns and cost modeling, DOE developed the following cost

efficiency relationships for standard and compact residential dish washers. The corresponding

cost

- efficiency curves are shown as follows.

5.5.3.1 Standard Dishwashers

For standard dish washers , DOE developed incremental manufacturing costs by tearing

down 12 units , and creating a cost model at each efficiency level. DOE started with the baseline

unit cost model , and at each higher efficiency level

, added in the observed cha nges associated with improving efficiency

. By doing this, DOE excluded the costs of any non

- efficiency related components from the more efficient units. The more efficient units are generally sold at a higher price point, and sometimes incl ude features t hat increase manufacturing cost, but are not necessarily efficiency

- r elated. One example of such a feature is the typical use of stainless steel wash tubs in more expensive units. Table 5.5.9 sho w s the incremental manufacturing costs from

DOE’s reverse

- engineering analysis.

Table 5.5

. 9 Standard Dishw asher Incremental Manufacturing Costs

Efficiency Level (Annual Energy Use, kWh/year ) Incremental Costs

($2010) ($/kWh) ($/gal)

Baseline (355)

- - -

EL 1 (324) $ 18.27 $0.59 $26.10

EL 2 (307) $31.82 $0.66 $21.21

EL 3 (295) $69.23 $1.15 $30.77

EL 4 (234) $75.18 $0.62 $27.85

EL 5 (180) $82.95 $0.47 $16.93

5.5.3.2 Compact Dishwashers

DOE developed the compact product class incremental manufacturing costs based on teardowns of three units. As with the standard product class, DOE started with the baseline unit cost model, and at each higher efficiency leve l, added in the observed changes associated with improving efficiency. There are very few, disparate compact platforms ( i.e. countertop units and dishdrawers) available on the market. Therefore, DOE weighted the costs at each efficiency5-22 level by market share of each platform. Table 5.5

. 10 sho w s t he incremental manufacturing costs for compact dishwashers as a result of DOE’s reverse

- engineering analysis.

Table 5.5

. 10 Compact Dishwasher Incremental Manufacturing Costs

Efficiency Level (Annual Energy Use, kWh/year ) Incremental Costs

($2010) ($/kWh) ($/gal)

Baseline (260)

- - -

EL 1 (222) $1.00 $ 0.03 $1.00

EL 2 (154) $12.11 $ 0.11 $ 5.05

5.5.4 Manufacturer Interviews

DOE conducted interviews with residential dish washer manufacturers to develop a better understanding of current product features and the technologies used to improve energy efficiency. The manufacturers interviewed represent a wide range of U

. S

. market share and

included both domestic and internation al companies that sell residential dish washers in the
United States

. During these interviews, DOE asked manufacturers questions about the following topics related to the engineering analysis :

**•** Design features of current baseline products

**•** Proposed increment al efficiency levels

**•** Design options required to meet each efficiency level

**•** Impacts on consumer utility

**•** Installation and repair costs as a function of efficiency

The discussion helped DOE understand what proposed design options have already been implemented and what additional design options DOE should consider. The manufacturers typically based their comments only on the standard product class because of the limi ted production of compact units.

The discussion below represents a consolidation of the manufacturer responses.5-23 5.5.4.1 Design F eatures of C urrent B aseline P roducts

DOE discussed with m anufacturers the features of baseline products identified during the

reverse

- en gineering analysis. The manufacturers generally agreed with DOE’s assumptions for a baseline unit, although not all manufacturers produce products at the baseline efficiency level.

5.5.4.2 Proposed Incremental Efficiency Levels

DOE asked manufacturers to commen t on the proposed efficiency levels for the standard and compact product classes. Manufacturers were asked to comment on the appropriateness of each incremental efficiency level, including the gap

- fill levels and the max

- tech levels. In general, manufactur ers did not object to the efficiency levels DOE selected for analysis. While discussing the proposed efficiency levels, multiple manufacturers expressed concerns with performance at the highest efficiency level, as discussed below in section 5.5.4.4

.

5.5.4.3 Design O ptions R equired to M eet E ach E fficiency L evel

DOE asked manufacturers to describe the changes associated with each active mode efficiency level relative to the baseli ne units in each product class. From the reverse

- engineering analysis, DOE developed a list of design options at each efficiency level, and requested

manufacturer feedback on t he list during the interviews.

Manufacturers generally agreed with DOE’s initial association of design options with the efficiency levels. The design options discussed in section 5.5.2.3 represent the design options

associated with each efficiency level based on DOE’s reverse

- engineering analysis, and feedback

from manufa cturers during the interviews.

DOE also used the interviews as an opportunity to clarify which design options are actually associated with improved energy and water perf ormance rather than consumer preference. For example, DOE learned that stainless steel wash tubs do not contribute significantly to a unit’s energy performance. Generally, consumers expect a stainless steel interior at higher price points, and more expen sive units are generally more efficient. In addition, DOE learned that the bitumen insulation on steel tubs improves noise performance, and actually increases energy consumption due to the bitumen’s thermal mass.

5.5.4.4 Impact on Consumer Utility

Each manufactur er interviewed expressed that there would be some tradeoff with the performance of a unit at the higher efficiency levels

. However, manufacturers differed in their opinions of how performance would be impacted. Certain manufacturers claimed wash performa nce could be maintained at all efficiency levels; however drying performance could be

affected . Other manufacturers claimed that consumers would not be satisfied with wash performance at EL 4 and EL 5. All manufacturers agreed that a certain minimum amou nt of5-24 energy and water is required to effectively wash dishes, and that the consumption levels cannot continuously decrease.

M anufacturers also expressed concerns that consumers could be unhappy with the increasing length of cycles associated with more eff icient units. The cycles lasting 2

– 3 hours are already at the limit consumers are willing to accept. Certain design options, such as a cold water inlet connection, would increase the cycle times even further. Certain manufacturers noted that achieving the energy and water use at EL 4 and EL 5 without significantly impacting consumer utility would require high

- cost technology options.

5.5.4.1 Installation and Repair Costs as a Function of Efficiency

Manufacturers differed in t heir opinion of repair costs as a function of efficiency. Some manufacturers expect no change in typical repair costs for more efficient units, while other s expect some increase due to more efficient units having more components. The manufacturers in

gen eral did not expect any major change in maintenance costs at higher efficiencies.

For installation costs, manufacturers pointed out that a cold water inlet connection, or dual hot and cold inlet connections, would increase installation costs. Dishwashers in the United States are typically connected to a hot water line, and as a result kitchens do not usually have a cold water line running to the dishwasher installation. For all other units, the manufacturers did not expect any change in installation costs

.