1 | Building Technologies Program eere.energy.gov

The Parker Ranch installation in Hawaii

BUILDING TECHNOLOGIES PROGRAM

Notice of Proposed Rulemaking 

Public Meeting:

Conventional Cooking Products 

Test Procedure

March 4, 2013

Ashley Armstrong

Department of Energy

Energy Efficiency & Renewable Energy
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4

3

2

Active Mode Test Procedure

Regulatory History

Covered Products

1 Introduction

5 Standby and Off Mode Test Procedure

Public Meeting Agenda

6 Compliance with EPCA Requirements
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Agenda

9:00 – 9:05 am Welcome

9:05 – 9:15 am Opening Remarks, Introductions, and Agenda Review

9:15 – 9:20 am Regulatory History

9:20 – 9:30 am Covered Products

9:30 – 10:30 am Active Mode Test Procedure

10:30 – 10:45 am Standby and Off Mode Test Procedure

10:45 – 11:00 am Compliance with EPCA Requirements

11:00 – 11:15 am Closing Remarks
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 NOPR published on January 30, 2013

 NOPR Public Meeting today, March 4, 2013

 Comments on NOPR from interested parties

• Transcript records oral comments from today’s public meeting

• Written comments (comment period closes 75 days after 

publication in the Federal Register, April 15, 2013)

 DOE reviews and considers all comments

 Final Rule Publication

Steps in the Test Procedure Rulemaking

Introduction

Final

Rule NOPR
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4

3

1

Active Mode Test Procedure

Introduction

Covered Products

2

5 Standby and Off Mode Test Procedure

Public Meeting Agenda

6 Compliance with EPCA Requirements

Regulatory History
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Legislative Background

 This test procedure rulemaking covers Appendix I of 10 CFR 

part 430, subpart B.

• The test procedures were established in a May 1978 Final Rule 

and amended in a May 1997 Final Rule.

• DOE published a Final Rule on October 31, 2012, to incorporate 

standby and off mode energy consumption, as well as the 

energy consumption of certain active mode features, into the test 

procedures for residential dishwashers, dehumidifiers, and 

conventional cooking products.

 The only existing energy conservation standards for 

conventional cooking products prohibit the use of a standing 

pilot light in all products manufactured after April 2012.

Regulatory History
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4

2

1

Active Mode Test Procedure

Introduction

Regulatory History

3

5 Standby and Off Mode Test Procedure

Public Meeting Agenda

6 Compliance with EPCA Requirements

Covered Products
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Test Procedure Applicability

 Induction cooking uses an oscillating magnetic field to 

generate (“induce”) current in the cooking vessel. The current 

in turn creates heat in the cooking vessel due to the electrical 

resistance of the metal, and the heat is transferred to the food 

load by means of conduction and convection.

 In order for the current to be induced and the induction 

technology to function properly, the cooking vessel must be 

made of a ferromagnetic material, such as steel or iron.

Covered Products
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Test Procedure Applicability

 Induction products were not considered in the initial final rule 

to establish the conventional cooking product test procedures 

because of their relatively small market share in 1978.

 A recent survey of major retailers indicates that roughly 10 

percent of all cooking tops currently available on the market 

use induction heating.

 The three manufacturers comprising more than 84 percent of 

the market for conventional ranges each offer multiple 

induction cooking products.

 Given the increased availability of induction cooking products, 

DOE believes these products warrant inclusion in the Appendix 

I test procedures.

Covered Products
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 10 CFR part 430.2 provides the following conventional cooking 

top product definition:

• Conventional cooking top means a class of kitchen ranges and 

ovens which is a household cooking appliance consisting of a 

horizontal surface containing one or more surface units which 

include either a gas flame or electric resistance heating.

 DOE is proposing to amend the definition of conventional 

cooking top:

• Conventional cooking top is a household cooking appliance 

within a class of kitchen ranges and ovens, each of which 

consists of a horizontal surface containing one or more surface 

units that utilize a gas flame, electric resistance heating, or 

electric inductive heating.

Covered Products

Test Procedure Applicability
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 10 CFR part 430.2 also provides a definition for conventional 

range:

• Conventional range means a class of kitchen ranges and ovens 

which is a household cooking appliance consisting of a 

conventional cooking top and one or more conventional ovens.

 DOE is not proposing any amendment to the definition of 

conventional range, but products with an induction cooking top 

and conventional oven would be considered conventional 

ranges under the proposed amendment to the definition of 

conventional cooking top. 

Covered Products

Test Procedure Applicability
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 Appendix I includes the following mode definition:

• Active mode means a mode in which the product is connected to 

a mains power source, has been activated, and is performing the 

main functions of producing heat by means of a gas flame, 

electric resistance heating, or microwave energy...

 DOE is proposing to amend the definition of active mode in 

Appendix I:

• Active mode means a mode in which the product is connected to 

a mains power source, has been activated, and is performing the 

main function of producing heat by means of a gas flame, 

electric resistance heating, electric inductive heating, or 

microwave energy... 

Covered Products

Test Procedure Applicability

(Current Definitions)
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Test Procedure Applicability

Covered Products

Comment Request #1

DOE requests comment on the proposed 

amendments to the definitions of “conventional 

cooking top” and “active mode” to include 

products that use electric inductive heating.

DOE notes that the definition of “conventional 

range” would remain unchanged, but would cover 

induction products based on the proposed 

amendment to the “conventional cooking top” 

definition.
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3

2

1

Covered Products

Introduction

Regulatory History

4

5 Standby and Off Mode Test Procedure

Public Meeting Agenda

6 Compliance with EPCA Requirements

Active Mode Test Procedure
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Current Test Procedure

 Process:

1. Select appropriate test block for the surface unit under test, and 

allow test block and cooking top to reach ambient temperature.

2. Turn surface unit to its maximum energy input setting.

3. After the test block temperature increases by 144 °F, reduce 

the surface unit setting to 25% of its maximum energy input 

rate.

4. Record data for 15 minutes at the reduced setting.

 Surface unit efficiency is calculated as the ratio of energy 

transferred to the test block (based on its increase in 

temperature) to the energy consumed by the cooking top 

during the test.

Active Mode Test Procedure
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Current Test Procedure

 Equipment:

 Aluminum Alloy 6061 is not ferromagnetic, and is therefore not 

compatible with induction cooking tops.

Active Mode Test Procedure

Material Test Block 

Size Used to Test Diameter (inches)

Height

(inches)

Aluminum 

Alloy 6061

Large

All gas surface units, electric 

surface units with diameter > 7 

inches

9 3

Small Electric surface units with 

diameter ≤ 7 inches 6.25 2.8
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Current Test Procedure

Active Mode Test Procedure

 Aluminum test blocks:
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Investigative Testing for Proposed Test Procedure

 DOE conducted testing on potential substitute test blocks that 

would be compatible with induction cooking tops.

• DOE followed the current testing procedure, but used different 

test blocks.

• The goal of the testing was to determine the effects of the 

different induction-compatible test blocks on test-to-test 

repeatability and efficiency.

• Testing included 3 conventional cooking tops (electric smoothtop, electric coil, and gas) and 3 induction cooking tops.

• Repeated the test 5 times for each test block type on each 

surface unit tested (except for the gas surface unit, which had 

the tests repeated 4 times).

Active Mode Test Procedure
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 For all candidate test blocks, DOE maintained the 6.25 and 9 

inch outer diameters, and maintained the overall heat capacity 

of the current aluminum test blocks by varying the heights of 

the substitute test blocks.

 DOE is proposing to amend the test procedure to replace the 

current aluminum test blocks with the stainless steel hybrid 

test blocks.

Test Blocks for Investigative Testing

Active Mode Test Procedure

Test Block Type Test Block Composition

(Component and Material)

Aluminum One solid aluminum alloy 6061 block

Carbon Steel One solid carbon steel alloy 1018 block

Carbon Steel Hybrid Carbon steel alloy 1018 base + Aluminum alloy 6061 body

Stainless Steel Hybrid Stainless steel alloy 430 base + Aluminum alloy 6061 body
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Test Blocks for Investigative Testing

Active Mode Test Procedure

 Carbon steel (large and small), stainless steel hybrid, and 

aluminum test blocks:
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Aluminum Test Block Results

 The aluminum test block results served as a baseline for 

comparing the different substitute test blocks.

• The aluminum test block results produced standard deviations of 

less than 3 percent for each surface unit tested.

• These standard deviations correspond to 95-percent confidence 

intervals within 4 percent of the mean surface unit efficiency.

 The substitute test blocks should result in similar or, if 

possible, better repeatability from test to test.

Active Mode Test Procedure
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Carbon Steel Test Blocks

 DOE tested carbon steel test blocks with the following 

properties:

 The test block diameters and overall heat capacities equal 

those of the aluminum test blocks. 

Active Mode Test Procedure

Material Test Block Size Diameter 

(inches)

Height

(inches)

Carbon Steel 

Alloy 1018

Large 9 2.09

Small 6.25 1.93
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Carbon Steel Test Block Results

 The carbon steel test blocks resulted in similar efficiencies to 

the aluminum test blocks for the three conventional test units.

 The carbon steel test blocks produced results with similar 

repeatability to the aluminum test blocks.

 The carbon steel test blocks appear to be a reasonable 

replacement for the aluminum test blocks; however, may not 

reflect how induction cooking tops operate in real-world 

scenarios.

Active Mode Test Procedure
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Carbon Steel Hybrid Test Blocks

 DOE tested “Hybrid” test blocks to better represent real-world 

use of induction cooking tops (i.e., heating of a thin 

ferromagnetic material rather than a solid block).

 Carbon steel hybrid blocks constructed of two separate pieces:

 The test block diameters and overall heat capacities equal 

those of the aluminum test blocks. 

Active Mode Test Procedure

Material Test Block Size Diameter 

(inches)

Height

(inches)

Carbon Steel Alloy 1018 Small Base 6.25 0.25

Aluminum Alloy 6061 Small Body 6.25 2.5

Carbon Steel Alloy 1018 Large Base 9 0.25

Aluminum Alloy 6061 Large Body 9 2.72
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Carbon Steel Hybrid Test Block Results

 The carbon steel hybrid test blocks produced efficiencies for 

the conventional surface units that were slightly lower than 

with both the solid carbon steel and aluminum test blocks, but 

within the 95-percent confidence intervals.

 For 5 of the 6 induction surface units, the carbon steel hybrid 

test blocks resulted in higher efficiencies than the solid carbon 

steel blocks.

• This suggests that heating the solid block could introduce 

inefficiencies with induction heating.

• However, while these increases in efficiency were typically small 

and within the 95-percent confidence intervals, the efficiency for 

one induction surface unit dropped significantly with the carbon 

steel hybrid test block.

Active Mode Test Procedure
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Carbon Steel Hybrid Test Block Results

 The test-to-test repeatability for the carbon steel hybrid test 

blocks was similar to both the carbon steel and aluminum test 

blocks.

 DOE observed rust forming on the carbon steel base 

throughout testing. The rust could lead to inconsistent heat 

transfer between the base and aluminum body.

• DOE also observed rust forming on the solid carbon steel test 

blocks. 

• The rust is likely to have more of an impact on the hybrid test 

blocks due to the additional heat transfer surface between the 

test block base and body.

Active Mode Test Procedure
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Stainless Steel Hybrid Test Blocks

 DOE conducted further testing using stainless steel hybrid test 

blocks, which would be more resistant to rust, constructed of 

two separate pieces:

 The test block diameters and overall heat capacities equal 

those of the aluminum test blocks. 

Active Mode Test Procedure

Material Test Block Size Diameter 

(inches)

Height

(inches)

Stainless Steel Alloy 430 Small Base 6.25 0.25

Aluminum Alloy 6061 Small Body 6.25 2.5

Stainless Steel Alloy 430 Large Base 9 0.25

Aluminum Alloy 6061 Large Body 9 2.72
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Stainless Steel Hybrid Test Block Results

 The stainless steel hybrid test blocks showed greater 

repeatability than the aluminum, carbon steel, and carbon steel 

hybrid test blocks.

 The stainless steel hybrid blocks also produced efficiency 

results that were on average 2.5 percentage points lower than 

for the carbon steel hybrid test blocks.

Active Mode Test Procedure
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All Test Block Results Comparison

Active Mode Test Procedure

Cooking

Tops Test Block Type Mean Efficiency

Standard 

Deviation

95-percent 

Confidence 

Interval (±)

Conventional

Only

Aluminum 56.02% 1.40% 1.80%

Carbon Steel 54.99% 1.32% 1.69%

Carbon Steel Hybrid 54.36% 1.13% 1.44%

Stainless Steel Hybrid 51.70% 1.03% 1.35%

All Cooking 

Tops

Carbon Steel 59.78% 1.36% 1.71%

Carbon Steel Hybrid 59.15% 1.36% 1.71%

Stainless Steel Hybrid 56.60% 1.10% 1.40%
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Test Block Proposal

 Because the stainless steel hybrid test blocks produced the 

most repeatable results, DOE is proposing to use these blocks 

for testing induction cooking tops.

 The conventional cooking top tests showed a drop of 4.3 

percentage points between the aluminum and stainless steel 

hybrid test blocks.

 DOE is proposing the use of the stainless steel hybrid test 

blocks for all covered cooking tops to allow a meaningful 

comparison of efficiency results among different product types. 

Active Mode Test Procedure
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Test Block Proposal

Active Mode Test Procedure

Comment Request #2

DOE seeks comment on its proposal to require the 

use of stainless steel hybrid test blocks for testing 

all cooking tops that would be covered by the 

proposed definition of conventional cooking tops 

in an amended cooking products test procedure, 

including the potential burden associated with the 

requirement for such new test equipment.
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Investigative Water-heating Tests

 DOE conducted a series of tests based on heating water rather 

than a metal block.

• Water provides a heating medium that is more representative of 

actual consumer use.

• However, water heating also introduces additional sources or 

variability absent from the block-heating tests.

 DOE conducted testing according to a Draft amendment to IEC 

Standard 60350-2 Edition 1.0 “Household electric cooking 

appliances – Part 2: Hobs – Method for measuring 

performance.”

Active Mode Test Procedure
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Investigative Water-heating Test Equipment

 The IEC Test Method specifies the quantity of water to be 

heated in a standardized cooking vessel based on the surface 

unit diameter.

 DOE chose the cooking vessels and water quantities that most 

closely matched the DOE test block diameters.

Active Mode Test Procedure

Cookware 

Size

Cookware 

Diameter 

(in)

Base 

Thickness 

(in)

Total 

Height 

(in)

Lid 

Diameter 

(in)

Water Weight 

(lbs)

Small 5.91 0.24 4.92 6.5 2.27

Large 9.45 0.24 4.92 10.43 5.95
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Investigative Water-heating Test Equipment

Active Mode Test Procedure

 Custom IEC Standard 60350-2 cookware:
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Investigative Water-heating Test Method

 The IEC Test Method involves heating the water to 194 °F using 

the maximum energy input rate, and then maintaining the water 

temperature above, but as close as possible, to this 

temperature for a simmering period of 20 min.

 Energy consumption is measured throughout the entire test, 

and the final metric describes the energy per 1000 grams of 

water necessary to reach and maintain the simmering 

temperature.

Active Mode Test Procedure
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Investigative Water-heating Test Method Concerns

 DOE observed the following issues during testing:

• The water approached boiling even at 194 °F, and a significant 

amount of water boiled or evaporated off over the course of a 

test.

• The simmering temperature and overall energy consumption 

varied from test-to-test on the same surface unit even at the 

same simmering setting.

 DOE developed an efficiency calculation to account for the total 

temperature rise and the amount of water lost during the test.

 The efficiency results also allowed for a more direct 

comparison to the block-heating test results.

Active Mode Test Procedure
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All Test Results Comparison

Active Mode Test Procedure

Cooking

Tops Test Type Mean Efficiency

Standard 

Deviation

95-percent 

Confidence 

Interval (±)

Conventional

Only

Aluminum 56.02% 1.40% 1.80%

Carbon Steel 54.99% 1.32% 1.69%

Carbon Steel Hybrid 54.36% 1.13% 1.44%

Stainless Steel Hybrid 51.70% 1.03% 1.35%

Water-heating 64.81% 2.70% 3.52%

All Cooking 

Tops

Carbon Steel 59.78% 1.36% 1.71%

Carbon Steel Hybrid 59.15% 1.36% 1.71%

Stainless Steel Hybrid 56.60% 1.10% 1.40%

Water-heating 71.63% 1.98% 2.54%
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Water-heating Test Method

 The test-to-test variability of the water-heating tests could be 

limited with more stringent tolerances on the ambient test 

conditions (air pressure, temperature, and humidity).

 DOE is not proposing a water-heating test procedure because it 

did not show any improvement in repeatability compared to the 

block-heating tests, and further ambient test condition controls 

could place a burden on manufacturers and third party test 

facilities.

Active Mode Test Procedure
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Water-heating Test Procedure

Active Mode Test Procedure

Comment Request #3

DOE acknowledges that the water-heating tests 

may better reflect actual consumer behavior for 

cooking tops, and invites comment on whether 

water-heating tests should be considered in place 

of the metal block-heating tests. DOE also invites 

comment on the appropriate test method and 

conditions for water-heating tests, and the burden 

that would be incurred by more stringent 

specifications for ambient conditions.
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Non-circular Electric Surface Units

 As previously discussed, the proper test block size for testing 

an electric surface unit is determined based on that surface 

unit’s diameter.

 The current test procedure does not specify the proper test 

block size for electric surface units with non-circular shapes.

 DOE proposes that an electric surface unit’s smallest 

dimension be used to determine appropriate test block size to 

account for surface units of all shapes.

• DOE notes that this is consistent with the method included in the 

Draft IEC Standard 60350 Amendment.

• DOE does not propose to change the requirement that all gas 

surface units be tested with the large test block.

Active Mode Test Procedure
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Non-circular Electric Surface Units

Active Mode Test Procedure

Comment Request #4

DOE invites comments on whether using the 

smallest dimension of an electric surface unit is 

appropriate for determining the proper test block 

size.
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3

2

1

Covered Products

Introduction

Regulatory History

5

4 Active Mode Test Procedure

Public Meeting Agenda

6 Compliance with EPCA Requirements

Standby and Off Mode Test Procedure
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Standby and Off Mode Test Procedure

 DOE recently conducted a separate rulemaking to address 

standby and off mode test procedures and certain active mode 

provisions for conventional cooking products, dishwashers, 

and dehumidifiers.

 For conventional cooking products, the October 2012 Final 

Rule addressed standby mode and off mode energy 

consumption and fan-only mode operation. 77 FR 65942.

Standby and Off Mode Test 

Procedure
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Standby and Off Mode Test Procedure

 This NOPR for induction cooking products proposes to amend 

the definition of “conventional cooking top” to include 

induction technology.

 Under this proposed definition, induction cooking products 

would be covered by the test procedure amendments made in 

the October 2012 Final Rule.

 DOE did not observe any standby or off mode features or fanonly mode operation unique to induction cooking products that 

would warrant any changes to the provisions established by 

the October 2012 Final Rule.

Standby and Off Mode Test 

Procedure
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Standby and Off Mode Test Procedure

Standby and Off Mode Test 

Procedure

Comment Request #5

DOE invites comment on whether induction 

cooking products require separate consideration 

for standby mode and off mode testing.
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2

1

Covered Products

Introduction

Regulatory History

6

5 Standby and Off Mode Test Procedure

Public Meeting Agenda

4 Active Mode Test Procedure

Compliance with EPCA Requirements
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Test Burden

 DOE tentatively concludes that the proposed test procedures 

would not be unduly burdensome to conduct.

• The additional cost for the new test blocks is roughly $1,000.

• No new instrumentation is required.

• The only additional time in the test procedure itself is for 

measuring the weight of two pieces of the test block rather than 

the current single piece.

• Additional testing would be required for the newly-covered 

induction products, and DOE estimates this would cost 

manufacturers up to roughly $6,000.

 DOE does not expect these cost or time commitments to 

represent a significant burden, including for small businesses.

Compliance with EPCA 

Requirements
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Compliance with Existing Standards

 DOE notes that the only existing standards for conventional 

cooking products require that gas cooking products shall not 

be equipped with a standing pilot light.

 As a result, the proposed test procedure amendments would 

not affect a product’s compliance with the existing standards.

Compliance with EPCA 

Requirements
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In all correspondence, please refer to the Induction Cooking Products Test Procedure rulemaking by:

– Test Procedure NOPR for Induction Cooking Products

– Docket Number EERE-2012-BT-TP-0013

– Regulatory Identification Number (RIN) 1904-AC71

Email: Induction-Cooking-Prod-2012-TP-0013@ee.doe.gov

Postal Mail: Ms. Brenda Jones, U.S. Department of Energy

Building Technologies Program, Mailstop EE-2J

1000 Independence Avenue, SW

Washington, DC 20585-0121

Courier: Ms. Brenda Jones, U.S. Department of Energy

Building Technologies Program 

950 L’Enfant Plaza, SW., Suite 600

Washington, DC, 20024.

Telephone: (202) 586-2945

Comment period closes April 15, 2013.

How to Submit Written Comments

Closing Remarks
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Results Appendix
51 | Building Technologies Program eere.energy.gov

a Values describe data for four tests, not five. In addition, cooking efficiencies 

for gas burners are typically lower than for electric resistance heating elements.

b Results lower than expected due to a meter error, but consistently low from 

test-to-test.

Aluminum Test Block Results

Active Mode Test Procedure

Test 

Block 

Size

Cooking 

Top

Heating 

Technology

Surface 

Unit

Mean 

Efficiency

Standard 

Deviation

95-percent 

Confidence 

Interval (±)

Large

A Coil 1 71.03% 2.22% 2.76%

B Smooth 1 54.22% 0.64% 0.80%

B Smooth 2 65.19% 1.06% 1.32%

C Gas 1 18.96%a,b 1.01%a 1.60%a

Small A Coil 2 65.04% 2.73% 3.39%

B Smooth 3 61.70% 0.73% 0.90%
52 | Building Technologies Program eere.energy.gov

a Values describe data for four tests, not five. In addition, cooking efficiencies for gas burners are 

typically lower than for electric resistance heating elements.

b Results lower than expected due to a meter error, but consistently low from test-to-test.

Carbon Steel Test Block Results

Active Mode Test Procedure

Test 

Block 

Size

Cooking 

Top

Heating 

Technology

Surface 

Unit

Mean 

Efficiency

Standard 

Deviation

95-percent 

Confidence 

Interval (±)

Large

A Coil 1 69.79% 1.59% 1.97%

B Smooth 1 53.19% 1.28% 1.60%

B Smooth 2 63.24% 2.03% 2.52%

C Gas 1 18.67%a,b 0.92%a 1.46%a

D Induction 1 63.92% 2.30% 2.86%

E Induction 1 67.78% 0.68% 0.84%

F Induction 1 67.93% 0.56% 0.70%

Small

A Coil 2 64.61% 0.54% 0.67%

B Smooth 3 60.44% 1.55% 1.93%

D Induction 2 64.10% 1.04% 1.29%

D Induction 3 60.89% 2.70% 3.35%

E Induction 2 62.86% 1.08% 1.34%
53 | Building Technologies Program eere.energy.gov

a Values describe data for four tests, not five. In addition, cooking efficiencies for gas burners are 

typically lower than for electric resistance heating elements.

b Results lower than expected due to a meter error, but consistently low from test-to-test.

Carbon Steel Hybrid Test Block Results

Active Mode Test Procedure

Test 

Block 

Size

Cooking 

Top

Heating 

Technology

Surface 

Unit

Mean 

Efficiency

Standard 

Deviation

95-percent 

Confidence 

Interval (±)

Large

A Coil 1 67.78% 1.87% 2.32%

B Smooth 1 52.03% 0.78% 0.97%

B Smooth 2 63.59% 0.64% 0.79%

C Gas 1 18.64%a,b 0.59%a 0.93%a

D Induction 1 65.94% 2.68% 3.32%

E Induction 1 68.17% 1.06% 1.31%

F Induction 1 60.10% 3.21% 3.99%

Small

A Coil 2 64.44% 1.87% 2.32%

B Smooth 3 59.71% 1.06% 1.32%

D Induction 2 63.26% 0.79% 0.98%

D Induction 3 62.88% 0.65% 0.81%

E Induction 2 63.27% 1.19% 1.48%
54 | Building Technologies Program eere.energy.gov

a Values describe data for four tests, not five. In addition, cooking efficiencies for gas burners are 

typically lower than for electric resistance heating elements.

b Results lower than expected due to a meter error, but consistently low from test-to-test.

Stainless Steel Hybrid Test Block Results

Active Mode Test Procedure

Test 

Block 

Size

Cooking 

Top

Heating 

Technology

Surface 

Unit

Mean 

Efficiency

Standard 

Deviation

95-percent 

Confidence 

Interval (±)

Large

A Coil 1 64.52% 0.87% 1.08%

B Smooth 1 49.19% 0.46% 0.57%

B Smooth 2 59.60% 0.46% 0.57%

C Gas 1 16.27%a,b 1.16%a 1.85%a

D Induction 1 64.19% 1.28% 1.59%

E Induction 1 64.32% 0.91% 1.13%

F Induction 1 55.57% 1.47% 1.83%

Small

A Coil 2 62.87% 2.36% 2.93%

B Smooth 3 57.75% 0.87% 1.08%

D Induction 2 62.83% 1.47% 1.83%

D Induction 3 60.29% 0.68% 0.84%

E Induction 2 61.81% 1.19% 1.47%
55 | Building Technologies Program eere.energy.gov

a Values describe data for four tests, not five. In addition, cooking efficiencies for gas burners are 

typically lower than for electric resistance heating elements.

b Results lower than expected due to a meter error, but consistently low from test-to-test.

Water-heating Test Results

Active Mode Test Procedure

Test 

Block 

Size

Cooking 

Top

Heating 

Technology

Surface 

Unit

Mean 

Efficiency

Standard 

Deviation

95-percent 

Confidence 

Interval (±)

Large

A Coil 1 79.81% 1.66% 2.06%

B Smooth 1 61.81% 2.83% 3.52%

B Smooth 2 75.88% 3.11% 3.86%

C Gas 1 26.29%a,b 2.83%a 4.51%a

D Induction 1 81.31% 0.28% 0.34%

E Induction 1 79.21% 0.65% 0.81%

F Induction 1 74.17% 2.55% 3.17%

Small

A Coil 2 76.99% 1.65% 2.05%

B Smooth 3 68.09% 4.12% 5.11%

D Induction 2 79.35% 0.37% 0.46%

D Induction 3 80.67% 1.71% 2.13%

E Induction 2 75.99% 2.03% 2.52%