1 | Building Technologies Program eere.energy.gov

The Parker Ranch installation in Hawaii

BUILDING TECHNOLOGIES PROGRAM

Notice of Proposed Rulemaking 

Public Meeting:

Microwave Oven (Active Mode)

Test Procedure

March 5, 2013

Ashley Armstrong

Department of Energy

Energy Efficiency & Renewable Energy
2 | Building Technologies Program eere.energy.gov

4

3

2

Test Methods for Microwave-Only Ovens

Covered Products

Consumer Usage

1 Introduction and Regulatory History

5 Test Methods for Convection Microwave Ovens

Public Meeting Agenda

6 Measures of Energy Consumption

7 Compliance with EPCA Requirements
3 | Building Technologies Program eere.energy.gov

 NOPR published on February 4, 2013

 NOPR Public Meeting today, March 5, 2013

 Comments on NOPR from interested parties

• Transcript records oral comments from today’s public meeting

• Written comments (comment period closes April 22, 2013)

 DOE reviews and considers all comments

 Final Rule Publication

Steps in the Test Procedure Rulemaking

Introduction

Final

Rule NOPR
4 | Building Technologies Program eere.energy.gov

Legislative Background

 Test Procedure Final Rule. 62 FR 51976, Oct. 3, 1997.

• Established microwave oven active mode test procedures in 10 CFR 

part 430, subpart B, appendix I.

• Incorporated by reference IEC Standard 705–Second Edition 1998 and 

Amendment 2–1993, “Methods for Measuring the Performance of 

Microwave Ovens for Households and Similar Purposes.”

 Test Procedure Repeal Final Rule. 75 FR 42579, July 22, 2010.

• Repealed the microwave oven active mode test procedure.

• DOE determined that the existing test procedure did not produce 

representative and repeatable test results.

• DOE was unaware of any test procedures that addressed the concerns 

with the cooking efficiency test procedure.

Regulatory History
5 | Building Technologies Program eere.energy.gov

Legislative Background

 Notice of Public Meeting. 75 FR 42611, July 22, 2010.

• Initiated a rulemaking to address active mode test procedures.

• DOE received no data or comments suggesting potential testing 

methods for microwave oven active mode.

 Request for Information Notice. 76 FR 65631, Oct. 24, 2011.

• Sought information and comments regarding representative and 

repeatable methods for measuring the microwave-only and convectionmicrowave cooking mode energy use.

• Interested parties comments:

- Real and artificial food loads do not produce repeatable and 

reproducible results.

- Interested parties commented that DOE should harmonize with IEC 

Standard 60705.

Regulatory History
6 | Building Technologies Program eere.energy.gov

Legislative Background

 Notice of Data Availability. 77 FR 33106, June 5, 2012.

• Presented test results and analytical approaches that DOE was 

considering for potential amendments.

• Considered microwave-only, convection-only, and convectionmicrowave cooking modes.

• Requested comment and information on test results.

Regulatory History
7 | Building Technologies Program eere.energy.gov

4

3

2

Test Methods for Microwave-Only Ovens

Covered Products

Consumer Usage

1 Introduction and Regulatory History

5 Test Methods for Convection Microwave Ovens

Public Meeting Agenda

6 Measures of Energy Consumption

7 Compliance with EPCA Requirements
8 | Building Technologies Program eere.energy.gov

Test Procedure Applicability

 10 CFR 430.2 provides the following definition:

• Microwave oven means a class of kitchen ranges and ovens which is a 

household cooking appliance consisting of a compartment designed to 

cook or heat food by means of microwave energy, including microwave 

ovens with or without thermal elements designed for surface browning 

of food and convection microwave ovens.

 Includes all ovens equipped with microwave capability, including 

convection microwave ovens.

 January 2013 TP Final Rule (standby/off mode) adopted a definition of 

convection microwave oven.

• Microwave oven that incorporates microwave capability, convection 

features, and any other cooking means in a single compartment.

Covered Products
9 | Building Technologies Program eere.energy.gov

Test Procedure Applicability

 All products that combine a microwave oven with other appliance 

functionality would be considered covered products.

• Microwave/conventional ranges, microwave/conventional ovens, 

microwave/conventional cooking tops, and other combined products.

 DOE proposes not to require such “combined products” be tested 

according to the proposed amendments. 

• Lack of information regarding appropriate testing methods and proper 

apportionment of energy use between the different functional 

components of the combined products.

Covered Products
10 | Building Technologies Program eere.energy.gov

4

3

2

Test Methods for Microwave-Only Ovens

Covered Products

Consumer Usage

1 Introduction and Regulatory History

5 Test Methods for Convection Microwave Ovens

Public Meeting Agenda

6 Measures of Energy Consumption

7 Compliance with EPCA Requirements
11 | Building Technologies Program eere.energy.gov

Consumer Usage Survey Data

 Lawrence Berkeley National Laboratory conducted a consumer usage 

survey in 2012 for microwave ovens.

• Collected data for microwave-only ovens (2258 households) and 

convection microwave ovens (653 households).

Consumer Usage

Product Mode

Cycle 

Length

(min)

Number of 

Annual 

Cycles

Annual 

Hours 

(min)

Microwave-Only Oven Microwave-Only 2.62 1026 44.9

Convection Microwave 

Oven

Microwave-Only 2.54 842 35.7

Convection-Only 18.70 101 31.7

Convection-Microwave 15.00 69 17.3
12 | Building Technologies Program eere.energy.gov

4

3

2

Test Methods for Microwave-Only Ovens

Covered Products

Consumer Usage

1 Introduction and Regulatory History

5 Test Methods for Convection Microwave Ovens

Public Meeting Agenda

6 Measures of Energy Consumption

7 Compliance with EPCA Requirements
13 | Building Technologies Program eere.energy.gov

Previous DOE Microwave Oven Test Procedure

 Previous DOE test procedure incorporated by reference IEC Standard 

705 for measuring active mode energy use.

• Measured the amount of energy required to raise the temperature of 1 

kg of water by 10 C ° under controlled conditions.

• The ratio of usable output power over input power described the energy 

factor (EF), a measure of the cooking efficiency.

Microwave-Only Ovens
14 | Building Technologies Program eere.energy.gov

IEC Standard 60705

 IEC published an updated version, IEC Standard 60705–Edition 4.0 

2010–04.

• Maintained the same basic testing methods as IEC Standard 705.

 IEC is in the process of revising its current test standard for 

microwave ovens, IEC Standard 60705.

• Latest draft version of IEC Standard 60705 was dated November 25, 

2011.

Microwave-Only Ovens
15 | Building Technologies Program eere.energy.gov

IEC Standard 60705 Test Method

 Draft revised IEC Standard 60705 includes a new test method that 

continues to use water as the cooking load.

• Measures the energy consumption required to heat water loads of 275 

g, 350 g, and 1000 g, in 600 ml, 900 ml, and 2000 ml borosilicate glass 

test containers, respectively, by 45 – 50 °C and 50 – 55 °C.

• The results for each load size are used to linearly interpolate the energy 

consumption required to heat the load by 50 °C.

• The cooking cycle energy consumption for each water load size is 

weighted based on consumer usage to calculate an average weighted 

per-cycle cooking energy consumption (275 g = 3/11; 350 g = 6/11; 

1000 g = 2/11).

Microwave-Only Ovens
16 | Building Technologies Program eere.energy.gov

IEC Standard 60705 Test Method

 Draft revised IEC Standard 60705 includes test methods for measuring 

the cooling down energy consumption.

• 15-minute measurement period after the completion of a 50 °C water 

load temperature rise cooking cycle. 

• Designed to measure the energy consumption associated with 

ventilating the microwave oven (i.e., operation of a fan) to cool down the 

cavity. 

• Included as an informative annex not required to be conducted. 

Microwave-Only Ovens
17 | Building Technologies Program eere.energy.gov

June 2012 NODA Test Results

 DOE presented results from testing to evaluate the repeatability of the 

draft revised IEC Standard 60705 cooking cycle test methods. 

Microwave-Only Ovens

Draft Revised IEC Standard 60705 

Cooking Cycle Test

275 g Water 

Load

350 g Water 

Load

1000 g Water 

Load

Overall 

Weighted

Energy 

Consumption (Wh)

Average 37.99 44.34 114.90 56.11

Min 32.54 39.14 104.86 50.35

Max 46.61 54.68 130.87 66.54

Test-to-Test 

Variation –

Standard Error (%)

Average 1.08 1.06 0.44 0.58

Min 0.05 0.10 0.09 0.03

Max 2.31 2.59 0.78 1.25
18 | Building Technologies Program eere.energy.gov

June 2012 NODA Test Results

 DOE conducted testing to evaluate the cooling down test method.

• Results showed minimal variation in the measured cooling down energy 

consumption from test to test and also between the different load sizes.

• For all test units, none contained a fan that operated at the end of the 

microwave-only cooking cycle.

• When the door was closed after the load was removed at the end of the 

cooking cycle, the microwave ovens reverted back to the standby mode. 

Microwave-Only Ovens
19 | Building Technologies Program eere.energy.gov

CENELEC Round-Robin Testing

 European Committee for Electrotechnical Standardization (CENELEC) 

conducted a round-robin testing program to evaluate the draft revised 

IEC Standard 60705.

• 5 manufacturer test labs and 5 independent test labs in Europe.

• 4 microwave oven models.

 CENELEC determined that the repeatability and reproducibility for the 

measured weighted cooking cycle and cooling down energy 

consumption to be acceptable

Microwave-Only Ovens

Mode Test-to-Test 

Variation (%)

Lab-to-Lab 

Variation (%)

Weighted Cooking Cycle 

Energy Consumption 0.56 2.30

Weighted Cooling Down 

Energy Consumption 0.24 6.14
20 | Building Technologies Program eere.energy.gov

Proposed Test Method

 DOE proposes to include provisions for measuring the microwaveonly active mode energy use based on the November 2011 draft IEC 

Standard 60705.

• Test methods produce repeatable and reproducible results.

 DOE also proposes additional language to clarify the application of 

these provisions.

Microwave-Only Ovens
21 | Building Technologies Program eere.energy.gov

Proposed Test Method – Definitions

 DOE proposes to define over-the-range as follows:

• The installation configuration for certain microwave ovens that are 

intended to be installed in the cabinetry above a conventional range or 

cooktop.

• Such products are supported by surrounding cabinetry, walls, or other 

similar structures on the sides, top, and/or rear of the product.

Microwave-Only Ovens
22 | Building Technologies Program eere.energy.gov

Proposed Test Method – Installation Conditions

 For over-the-range microwave ovens, products equipped with a fan 

designed to vent air out of the microwave oven cooking cavity offer 

two installation configurations:

• Vent fan exhausts air from the cooking cavity to the outdoors.

• Vent fan recirculates air from the cooking cavity back into room.

 DOE proposes to require that over-the-range microwave ovens be 

installed with the exhaust vent/recirculation fan in the recirculation 

configuration.

• Default configuration for most products in DOE’s test sample.

• Minimizes burden by not requiring test room be capable of outdoor 

venting.

• Provide consistent method for all products.

Microwave-Only Ovens
23 | Building Technologies Program eere.energy.gov

Proposed Test Method – Setup

 November 2011 draft IEC Standard 60705 specifies that at the 

beginning of each test, the oven shall not have been operated for a 

period of at least 6 hours before each test.

• Temperature of the magnetron and power supply shall be within 2 °C of 

the ambient temperature.

• Forced cooling may be used to assist in cooling the component 

temperatures to ambient conditions. 

 Appendix I specifies that all areas of the appliance shall attain the 

normal nonoperating temperature before any test.

• Defined as the temperature that the appliance would attain if it remained 

in the test room for 24 hours ± 2.8 °C.

 DOE is not proposing to amend the normal nonoperating temperature 

currently specified in appendix I.

Microwave-Only Ovens
24 | Building Technologies Program eere.energy.gov

Proposed Test Method – Insulating Pads

 November 2011 draft IEC Standard 60705 specifies that the water test 

load be placed on a thermally insulating pad when making 

temperature measurements.

 DOE proposes to require the use of an insulating pad with a heat 

capacity of 1.30 kJ/kg-K or less, which is the heat capacity of 

polystyrene.

• Effectively insulates water test load while making temperature 

measurements.

Microwave-Only Ovens
25 | Building Technologies Program eere.energy.gov

Proposed Test Method – Fan-Only Mode

 DOE proposes to measure the fan-only mode cooling down energy 

consumption only for products equipped with a fan that operates 

automatically at the completion of the cooking cycle.

• None of the microwave ovens in DOE’s test sample were equipped with 

a fan that operated at the end of the microwave-only cooking cycle.

• May be microwave ovens on the market or future products that could 

potentially operate in fan-only mode at the end of the microwave-only 

cooking cycle.

 DOE proposes to define fan-only mode as follows:

• A mode that is not user-selectable and in which a fan circulates air 

internally or externally to the microwave oven for a finite period of time 

after the end of the cooking cycle.

Microwave-Only Ovens
26 | Building Technologies Program eere.energy.gov

Proposed Test Method – Fan-Only Mode

 DOE proposes to measure fan-only mode based on the provisions in 

the November 2011 draft IEC Standard 60705, with the following 

modification:

• Measure the fan-only mode energy consumption and duration rather 

than for a fixed 15-minute period.

 DOE is not aware of the typical duration of fan-only mode operation 

after the microwave-only cooking cycle.

• November 2011 draft IEC Standard 60705 specifies that the test load 

should be removed from the microwave oven and the door closed within 

30 ± 2 seconds after the completion of the cooking cycle.

• DOE recognizes that for a shorter cycle time, the duration of the fanonly mode may only be a short period of time.

Microwave-Only Ovens
27 | Building Technologies Program eere.energy.gov

Proposed Test Method – Repeat Tests

 November 2011 draft IEC Standard 60705 does not require multiple 

repeat test runs.

 DOE believes requiring multiple repeat test runs will improve the 

accuracy of test results.

• DOE proposes to require that the full microwave-only test series be 

repeated three times unless the total per-cycle energy consumption for 

the second measurement is within 1.5 percent of the value obtained 

from the first measurement.

Microwave-Only Ovens
28 | Building Technologies Program eere.energy.gov

Microwave-Only Oven Test Method

Microwave-Only Ovens

Comment Request #1

DOE seeks comment on the proposal to measure the active mode 

energy use of the microwave-only cooking mode for microwaveonly ovens based on the provisions in the November 2011 draft IEC 

Standard 60705. DOE also seeks comment on the requirement to 

repeat the full microwave-only test series three times unless the 

total microwave-only per-cycle energy consumption for the second 

measurement is within 1.5 percent of the value obtained from the 

first measurement. 
29 | Building Technologies Program eere.energy.gov

Fan-Only Mode

Microwave-Only Ovens

Comment Request #3

DOE seeks comment on the proposal to require that the microwaveonly fan-only mode be measured for only those products that are 

capable of operating in fan-only mode. DOE welcomes comment on 

the proposed requirement to measure the fan-only mode until the 

end of the fan-only mode, rather than for a fixed period of time. DOE 

also welcomes comment on whether the proposed requirement to 

close the microwave oven door within 30 ± 2 after the completion of 

the microwave-only cooking cycle is appropriate to accurately 

measure the microwave-only fan-only mode energy use. 
30 | Building Technologies Program eere.energy.gov

Food Simulation Mixture Test Loads

 For the June 2012 NODA, DOE conducted testing using the 

microwave-only cooking mode to evaluate mixtures that would 

simulate food loads that may be heated in a microwave.

• Mixtures were composed of water and basic food ingredients (i.e., fats, 

sugars, salt, fiber, proteins, etc.) with a total combined mass of 350 g. 

• Ingredients composing each mixture were based on nutritional labels of 

commonly microwaved foods. 

• DOE also tested mixtures with only one or two key ingredients. 

 Test results showed a higher range and average test-to-test variation 

compared to the water-only test load.

 DOE is not proposing to require the use of real or simulated food 

loads.

Microwave-Only Ovens
31 | Building Technologies Program eere.energy.gov

4

3

2

Test Methods for Microwave-Only Ovens

Covered Products

Consumer Usage

1 Introduction and Regulatory History

5 Test Methods for Convection Microwave Ovens

Public Meeting Agenda

6 Measures of Energy Consumption

7 Compliance with EPCA Requirements
32 | Building Technologies Program eere.energy.gov

Convection Microwave Ovens

 Typically can be operated using the microwave-only cooking mode, 

convection-only cooking mode, and convection-microwave cooking 

mode.

 Convection microwave ovens represent a significant number of 

shipments and warrant separate test methods.

• ~4.1 percent of U.S. microwave oven shipments (~400,000 annual 

shipments).

• Total Annual Energy Consumption:

- Convection-only cooking mode represents ~28.2 percent.

- Convection-microwave cooking mode represents ~16.9 percent.

Convection Microwave Ovens
33 | Building Technologies Program eere.energy.gov

Proposed Test Method – Microwave-Only Mode

 DOE proposes to measure the energy consumption of the microwaveonly cooking mode for convection microwave ovens using the test 

procedures described previously.

• Based on the November 2011 draft IEC Standard 60705, with added 

clarifications.

Convection Microwave Ovens

Comment Request #2

DOE seeks comment on the proposal to measure the active mode 

energy use of the microwave-only cooking mode for convection 

microwave ovens based on the provisions in the November 2011 

draft IEC Standard 60705. 
34 | Building Technologies Program eere.energy.gov

Convection-Only Mode – June 2012 NODA

 For the June 2012 NODA, DOE developed a test method for the 

convection-only mode based on the DOE conventional oven test 

procedure.

 DOE conventional oven test procedure:

• Temperature control for the convection cooking cycle is set such that 

the temperature inside the oven is 325 ± 5 °F higher than the room 

ambient air temperature (77 ± 9 °F).

• An 8.5 ± 0.1 pound cylindrical aluminum test block is heated from 

ambient room air temperature ± 4 °F until the test block temperature has 

increased 234 °F above its initial temperature.

• The measured energy consumption is used to calculate the cooking 

efficiency and energy factor.

Convection Microwave Ovens
35 | Building Technologies Program eere.energy.gov

Convection-Only Mode – June 2012 NODA

 Cavity temperature requirement of 325 ± 5 °F higher than the room 

ambient air temperature would result in a temperature setting close to 

400 °F.

• A number of convection microwave ovens on the U.S. market do not 

have a 400 °F temperature setting, but all products that DOE surveyed 

have a 375 °F temperature setting. 

 DOE modified the test method to conduct this testing using a 

temperature control setting of 375 °F to heat the aluminum test block to 

234 °F above its initial temperature.

 DOE specified that the aluminum test block be placed on the metal 

cooking rack provided by the manufacturer. 

Convection Microwave Ovens
36 | Building Technologies Program eere.energy.gov

Convection-Only Mode – June 2012 NODA

 Test results for the convection-only cooking cycle. 

Convection Microwave Ovens

Convection-Only

Cooking Cycle

Cooking Efficiency (%)

Average 9.06

Min 6.51

Max 12.42

Test-to-Test Variation –

Standard Error (%)

Average 1.30

Min 0.68

Max 2.11
37 | Building Technologies Program eere.energy.gov

Proposed Test Method – Convection-Only Mode

 DOE proposes to measure the convection-only cooking mode energy 

consumption based on the test methods described previously, with 

additional clarifications. 

 DOE proposes to require that if the convection microwave oven allows 

for the turntable to be turned on or off, it shall be tested with the 

turntable turned on. 

• Turntable is typically turned on by default, and as a result, is likely the 

most common configuration used by consumers.

Convection Microwave Ovens
38 | Building Technologies Program eere.energy.gov

Proposed Test Method – Convection-Only Mode

 DOE proposes to require that the energy use and duration of the fanonly mode be measured at the end of the convection-only cooking 

cycle until the completion of the fan-only mode. 

• Based on DOE testing, the duration of the fan-only mode was between 

0 and 7 minutes.

• Added test time is minimal compared to the overall convection-only 

cooking test cycle length.

Convection Microwave Ovens
39 | Building Technologies Program eere.energy.gov

Proposed Test Method – Convection-Only Mode

 DOE proposes to calculate the convection-only cooking cycle energy 

consumption using the same basic calculations used for the 

conventional oven test procedure.

• Convection-only cooking cycle and fan-only mode energy consumption 

added together to calculate the convection-only mode energy 

consumption.

• Field use factor (0.26) applied to the calculation of the convection-only 

mode energy consumption to account for the typical consumer use.

- Average convection-only cooking cycle length according to 

consumer use data (18.70 minutes) divided by the average 

measured test length for the units in DOE’s test sample (72.68 

minutes). 

Convection Microwave Ovens
40 | Building Technologies Program eere.energy.gov

Proposed Test Method – Convection-Only Mode

 DOE proposes to require that the convection-only test be repeated 

three times unless the total convection-only per-cycle energy 

consumption for the second measurement is within 1.5 percent of the 

value obtained from the first measurement.

• Improve the accuracy of test results. 

Convection Microwave Ovens
41 | Building Technologies Program eere.energy.gov

Convection Microwave Oven – Convection-Only Mode

Convection Microwave Ovens

Comment Request #2

DOE seeks comment on the proposal to measure the active mode 

energy use of the convection-only cooking mode for convection 

microwave ovens based on the provisions in the DOE conventional 

oven test procedure in 10 CFR part 430, subpart B, appendix I, with 

additional modifications specific for microwave ovens. DOE also 

seeks comment on the requirement to repeat the convection-only 

test three times unless the total convection-only per-cycle energy 

consumption for the second measurement is within 1.5 percent of 

the value obtained from the first measurement. 
42 | Building Technologies Program eere.energy.gov

Convection Microwave Oven – Fan-Only Mode

Convection Microwave Ovens

Comment Request #3

DOE seeks comment on the proposal to require that the convectiononly fan-only mode be measured for only those products that are 

capable of operating in fan-only mode. DOE welcomes comment on 

the proposed requirement to measure the fan-only mode until the 

end of the fan-only mode, rather than for a fixed period of time. 
43 | Building Technologies Program eere.energy.gov

Convection-Microwave Mode – June 2012 NODA

 In the June 2012 NODA, DOE presented test results to evaluate test 

loads and methods for measuring the energy use of the convectionmicrowave cooking mode.

• Real food loads – Crisco® all-vegetable shortening, Russet Burbank 

potatoes, and USDA grade A boneless chicken breasts.

• Simulation food loads – TX-151 solidifying gel.

 Test results for both real and simulation food loads showed high testto-test variation.

 Lab-to-lab reproducibility would be difficult to maintain.

 DOE is not proposing to require the use of real or simulated food 

loads for measuring the energy consumption of convection microwave 

ovens.

Convection Microwave Ovens
44 | Building Technologies Program eere.energy.gov

Proposed Test Method – Convection-Microwave Mode

 DOE proposes to use the results from the microwave-only and 

convection-only cooking cycle tests to determine the convectionmicrowave cooking cycle energy consumption.

 DOE is proposing to apply a field use adjustment to both the per-cycle 

microwave-only and convection-only cooking energy consumption.

• Based on the ratio of the convection-microwave cooking cycle length to 

either the microwave-only cycle length (15.00 / 2.54 = 5.91) or 

convection-only cooking cycle length (15.00 / 18.70 = 0.80) based on 

consumer use data.

Convection Microwave Ovens
45 | Building Technologies Program eere.energy.gov

Proposed Test Method – Convection-Microwave Mode

 Per-cycle convection-microwave cooking mode energy consumption 

would be calculated by apportioning the microwave-only cooking and 

convection-only cooking energy consumption.

• Based on the amount of time typical convection microwave ovens use 

each cooking mode during a convection-microwave cooking cycle.

• Default convection-microwave cooking mode program cycles between 

microwave-only cooking and convection-only cooking.

 DOE proposes to use weighting factors of 30 percent for microwaveonly cooking and 70 percent for convection-only cooking.

• For a single cooking cycle, the microwave-only cooking accounted for 

30 percent of the cooking time and convection-only cooking accounted 

for the remaining 70 percent of the total cooking time per-cycle on 

average for all of DOE’s test units.

Convection Microwave Ovens
46 | Building Technologies Program eere.energy.gov

Convection-Microwave Mode

Convection Microwave Ovens

Comment Request #2

DOE seeks comment on the proposed method for calculating the 

energy use of the convection-microwave cooking mode based on 

the test results from the microwave-only and convection-only tests.
47 | Building Technologies Program eere.energy.gov

4

3

2

Test Methods for Microwave-Only Ovens

Covered Products

Consumer Usage

1 Introduction and Regulatory History

5 Test Methods for Convection Microwave Ovens

Public Meeting Agenda

6 Measures of Energy Consumption

7 Compliance with EPCA Requirements
48 | Building Technologies Program eere.energy.gov

Estimates of Annual Consumer Use

 To develop an integrated metric that combines the active mode energy 

consumption of each possible cooking mode with the standby and off 

mode energy consumption, DOE evaluated the data from the 

consumer use survey conducted by LBNL.

 Microwave-only Oven Annual Consumer Use:

Measures of Energy Consumption

Mode

Cycle 

Length 

(min)

Number of 

Annual 

Cycles

Annual 

Hours 

(hour)

Average 

Power

(W)

Annual 

Energy Use 

(kWh)

Microwave-Only 

Cooking 2.62 1026 44.9 1582.7 71.063

Microwave-Only FanOnly Mode 0 0 0 0 0

Standby/Off - - 8715.1 2.7 23.531
49 | Building Technologies Program eere.energy.gov

Convection Microwave Oven Annual Consumer Use

*

Estimates are based on a microwave oven that is capable of operating in fan-only mode. The 

average fan-only mode cycle length was determined based DOE’s testing.

Measures of Energy Consumption

Mode

Cycle 

Length 

(min)

Number of 

Annual 

Cycles

Annual 

Hours 

(hour)

Average 

Power

(W)

Annual 

Energy Use 

(kWh)

Microwave-Only 

Cooking 2.54 842 35.7 1582.7 56.502

Convection-Only 

Cooking 18.70 101 31.7 1299.4 41.191

Convection-Microwave 

Cooking 15.00 69 17.3 1421.3 24.588

Microwave-Only FanOnly Mode 0 0 0 0 0

Convection-Only FanOnly Mode 1.10* 101 1.9 39.1 0.074

Convection-Microwave 

Fan-Only 0.88* 69 1.0 39.1 0.039

Standby/Off - - 8672.4 2.7 23.415
50 | Building Technologies Program eere.energy.gov

Annual Energy Use Calculation

 DOE proposes to use the estimates of consumer use for each 

operating mode to calculate the total annual energy consumption for 

both microwave-only ovens and convection-microwave ovens.

 Microwave-only ovens:

1. Calculate the product of the total weighted microwave-only per-cycle 

energy consumption and the number of annual microwave-only 

cooking cycles for microwave-only ovens.

2. Calculate the products of the average standby and off mode power 

and the allocated annual hours for each respective mode;

3. Sum these results; and

4. Multiply the sum by 0.001 to convert from Wh to kWh.

Measures of Energy Consumption
51 | Building Technologies Program eere.energy.gov

Annual Energy Use Calculation

 Convection microwave ovens:

1. Calculate the products of the microwave-only mode, convection-only 

mode, and convection-microwave mode per-cycle energy 

consumption and the number of annual cooking cycles for each mode 

for convection microwave ovens;

2. Calculate the products of the average standby and off mode power 

and the allocated annual hours for each respective mode;

3. Sum these results; and

4. Multiply the sum by 0.001 to convert from Wh to kWh.

Measures of Energy Consumption
52 | Building Technologies Program eere.energy.gov

Standby and Off Mode Hours

 Total standby and off mode hours:

• Number of total hours in a year (8760) minus the average cooking cycle 

times based on consumer use and the measured fan-only mode times 

for each cooking mode.

 Split between standby and off mode hours:

• DOE is unaware of any microwave ovens capable of operating in both 

standby mode and off mode.

• DOE proposes to split the total hours evenly between standby and off 

modes for products capable of functioning in both modes.

Measures of Energy Consumption
53 | Building Technologies Program eere.energy.gov

Convection-Only Fan-Only Mode Hours

 DOE proposes to scale the measured convection-only fan-only mode 

time using the convection-only cooking cycle length field use factor 

(0.26).

• The convection-only fan-only mode time measured under the proposed 

test procedure would be based on a longer cooking cycle.

Measures of Energy Consumption
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Convection-Microwave Mode Fan-Only Mode Hours

 DOE believes that the fan-only mode time would likely be equivalent 

for a convection-only cooking and convection-microwave cooking 

cycle of the same length.

• Microwave ovens that operate in fan-only mode after the convectiononly cooking cycle also operate in fan-only mode after the convectionmicrowave cooking cycle. 

• The fan-only mode duration is based on either the cavity temperature or 

a fixed time based on the cooking cycle length.

 DOE proposes to use the convection-only fan-only mode time, but 

scaled by the difference between the average convection-microwave 

cooking and convection-only cooking cycle lengths based on the 

consumer use data (15.00 min / 18.70 min).

Measures of Energy Consumption
55 | Building Technologies Program eere.energy.gov

Integrated Annual Energy Use Metric

Active Mode Test Procedure

Comment Request #4

DOE seeks comment on the proposal to establish an integrated 

annual energy use metric. DOE specifically seeks comment and 

additional data on the consumer usage habits for each operating 

mode for both microwave-only ovens and convection microwave 

ovens to supplement the data from the LBNL consumer use survey. 
56 | Building Technologies Program eere.energy.gov

4

3

2

Test Methods for Microwave-Only Ovens

Covered Products

Consumer Usage

1 Introduction and Regulatory History

5 Test Methods for Convection Microwave Ovens

Public Meeting Agenda

6 Measures of Energy Consumption

7 Compliance with EPCA Requirements
57 | Building Technologies Program eere.energy.gov

Test Burden

 Microwave-only mode:

• Similar test equipment cost to previous DOE test procedure.

• Two additional sized test container (600 ml and 900 ml).

• One-time investment for test equipment of ~$3,000 ($300 more than 

previous DOE test procedure).

• Labor for testing a single model would cost between $3,000 and $4,200, 

depending on the number of repeat tests required ($2,600 to $3,600 

more than the labor for the previous DOE test procedure).

Compliance with EPCA 

Requirements
58 | Building Technologies Program eere.energy.gov

Test Burden

 Convection-only Mode:

• Similar requirements to DOE conventional oven test procedure.

• One-time investment for test equipment would add $400.

• Labor for testing a single model would cost between $600 and $850, 

depending on the number of repeat tests required.

 DOE does not expect these cost or time commitments to represent a 

significant burden.

 DOE tentatively concludes that the proposed amended test 

procedures would not be unduly burdensome to conduct.

Compliance with EPCA 

Requirements
59 | Building Technologies Program eere.energy.gov

Test Burden

Compliance with EPCA 

Requirements

Comment Request #5

DOE welcomes comment on the testing burden associated with the 

proposed amendments, in particular for the microwave-only and 

convection-only test methods. When providing comments, please 

quantify and describe the associated testing burdens (in terms of 

cost and time). 
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In all correspondence, please refer to the Microwave Oven (Active Mode) Test Procedure rulemaking by:

– Test Procedure NOPR for Microwave Ovens (Active Mode)

– Docket Number EERE-2010-BT-TP-0023

– Regulatory Identification Number (RIN) 1904-AC26

Email: MWO-2010-TP-0023@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 22, 2013

How to Submit Written Comments

Closing Remarks