ENERGYSTAR
ENERGY STAR® Program Requirements
for Single Voltage External Ac-Dc and Ac-Ac Power Supplies
Eligibility Criteria
Table of Contents
Section 1: Definitions
Section 2: Qualifying Products
Section 3: Energy-Efficiency Specifications for Qualifying Products
Table 1: Energy-Efficiency Criteria for Active Mode
Table 2: Examples of Minimum Average Efficiency in Active Mode
Table 3: Energy Consumption Criteria for No-Load
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4
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Section 4: Test Methodology
Section 5: Effective Date
Section 6: Future Specification Revisions
Section 7: International Efficiency Marking Protocol
Figure 1: Illustration of International Efficiency Mark
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ENERGY STAR Program Requirements for External Power Supplies (Version 1.1)

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ERGYSTA
ENERGY STAR® Program Requirements
for Single Voltage External Ac-Dc and Ac-Ac Power Supplies
Eligibility Criteria (Version 1.1)
Below is the product specification (Version 1.1) for ENERGY STAR qualified single voltage external ac-dc
and ac-ac power supplies. A product must meet all of the identified criteria if it is to be qualified as
ENERGY STAR by its external power supply manufacturer.
The goal of this ENERGY STAR external power supply specification is to recognize those models with an
efficient ac-dc or ac-ac conversion process. This specification along with its complement, the specification
for products with battery charging systems (BCSs), intends to comprehensively cover the full range of
energy conversion products. Manufacturers shall carefully examine their product designs and compare
them to the detailed definitions (Section 1) and qualifying product descriptions (Section 2) for an external
power supply and battery charging system (visit
http://www.enerqystar.qov/index.cfm?c=batterv chargers.pr battery chargers) to determine the
appropriate specification for ENERGY STAR qualification. Manufacturers may only qualify individual
models under the one specification (i.e., external power supply OR battery charging system) that best
reflects the power supply and product design.
1) Definitions: EPA has prepared detailed definitions of single voltage external ac-dc and ac-ac power
supplies and other related terms as relevant to ENERGY STAR.
A.	Single Voltage External Ac-Dc Power Supply: For the purposes of this specification, a single
voltage external ac-dc power supply:
a)	is designed to convert line voltage ac input into lower voltage dc output;
b)	is able to convert to only one dc output voltage at a time;
c)	is sold with, or intended to be used with, a separate end-use product that constitutes the
primary load;
d)	is contained in a separate physical enclosure1 from the end-use product;
e)	is connected to the end-use product via a removable or hard-wired male/female electrical
connection, cable, cord or other wiring;
f)	does not have batteries or battery packs that physically attach directly (including those
that are removable) to the power supply unit;
g)	does not have a battery chemistry or type selector switch AND an indicator light or state
of charge meter (e.g., a product with a type selector switch AND a state of charge meter is
excluded from this specification; a product with only an indicator light is still covered by
this specification); and
h)	has nameplate output power less than or equal to 250 watts.
B.	Single Voltage External Ac-Ac Power Supply: For the purpose of this specification, a single
voltage external ac-ac power supply:
a)	is designed to convert line voltage ac input into lower voltage ac output;
b)	is able to convert to only one ac output voltage at a time;
c)	is sold with, or intended to be used with, a separate end-use product that constitutes the
primary load;
d)	is contained in a separate physical enclosure1 from the end-use product;
e)	is connected to the end-use product via a removable or hard-wired male/female electrical
connection, cable, cord or other wiring;
f)	does not have batteries or battery packs that physically attach directly (including those
that are removable) to the power supply unit;
g)	does not have a battery chemistry or type selector switch AND an indicator light or state
of charge meter (e.g., a product with a type selector switch AND a state of charge meter is
excluded from this specification; a product with only an indicator light is still covered by
1 "Physical enclosure" refers to the housing of the products themselves, not their retail packaging.
ENERGY STAR Program Requirements for External Power Supplies (Version 1.1)

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this specification); and
h) has nameplate output power less than or equal to 250 watts.
C.	Active Mode: The condition in which the input of a power supply is connected to line voltage ac
and the output is connected to a dc or an ac load drawing a fraction of the power supply's
nameplate power output greater than zero.
D.	No-Load Mode: The condition in which the input of a power supply is connected to an ac source
consistent with the power supply's nameplate ac voltage, but the output is not connected to a
product or any other load.
2)	Qualifying Products: In order to qualify as ENERGY STAR, an external power supply model must
meet the definition in Section 1 .A or 1 .B and the specification requirements provided in Section 3,
below.
3)	Energy-Efficiency Specifications for Qualifying Products: Only those products in Section 2 that
meet the following criteria for both Active and No-Load Modes may qualify as ENERGY STAR.
A. Active Mode
1. Tier 1: To be eligible for ENERGY STAR qualification, an external power supply model must
meet or exceed a minimum average efficiency for Active Mode, which varies based on the
model's nameplate output power. Table 1 below outlines the equations for determining
minimum average efficiency where Pno stands for nameplate output power and Ln refers to
the natural logarithm. Efficiency shall be expressed in decimal form and rounded to the
hundredths place.
Table 1: Energy-Efficiency Criteria for Active Mode
Nameplate Output Power (Pno)
Minimum Average Efficiency in Active
Mode (expressed as a decimal)2
0 to < 1 watt
> 0.49 * Pno
> 1 to < 49 watts
> [0.09 * Ln (Pno)l + 0.49
> 49 watts
>0.84
Examples to Illustrate the Active Mode Approach: Average Active Mode efficiency and ENERGY
STAR qualification shall be determined as follows:
Calculate the model's single average Active Mode efficiency value by testing at 100%, 75%, 50%,
and 25% of rated current output and then computing the simple arithmetic average of these four
values, as specified in the Test Method.
Based on the model's nameplate output power, select the appropriate equation from Table 1 and
calculate the minimum average efficiency.
Compare the model's actual average efficiency to the minimum average efficiency required by
ENERGY STAR. If actual average efficiency is greater than or equal to the minimum average
efficiency, the model has satisfied ENERGY STAR'S Active Mode requirement.
To provide an example using the criteria in Table 1, the minimum average efficiencies required of
three sample power supplies are provided in Table 2 below. As shown in the last column, power
supplies 1, 2, and 3 would meet the ENERGY STAR Active Mode requirement if they had average
efficiencies of at least 25%, 76%, and 84%, respectively. Therefore, if Power Supply 1 in Table 2 had
an actual average efficiency of 30%, it would satisfy the Active Mode requirement because it
surpassed the ENERGY STAR minimum average efficiency of 25%.
2 (a) "Ln" refers to the natural logarithm. The algebraic order of operations requires that the natural logarithm
calculation be performed first and then multiplied by 0.09, with the resulting output added to 0.49. (b) An efficiency of
0.84 in decimal form corresponds to the more familiar value of 84% when expressed as a percentage.
ENERGY STAR Program Requirements for External Power Supplies (Version 1.1)	3

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Table 2: Examples of Minimum Average Efficiency in Active Mode
Sample
Nameplate Output
Power (Pno)
Average Efficiency in Active Mode
(expressed as a decimal)
Power Supply 1
0.5 watts
0.49*0.5 = 0.25
Power Supply 2
20 watts
[0.09 * Ln (20)] + 0.49 = 0.759616 or 0.76
Power Supply 3
75 watts
0.84
2. Tier 2: To continually recognize the most efficient models on the market and reflect
forthcoming improvements in technology, EPA plans to implement a Tier 2 Active Mode
specification. Approximately one year before the Tier 2 effective date, EPA will: 1) collect
efficiency data (based on the ENERGY STAR Test Methodology) on a wide range of external
power supplies (varying in terms of size, efficiency, manufacturer, cost, and other parameters)
sold in markets throughout the world; 2) analyze the data to identify appropriate levels of
efficiency; 3) release the proposed Tier 2 specification for stakeholder review and comment
(focusing on the technical elements of Tier 2 and not on all programmatic details); and 4)
finalize the specification based on stakeholder comments. EPA has a target effective date of
January 1, 2008 for a Tier 2 specification.
B. No-Load Mode
1. Tier 1: The second half of the ENERGY STAR specification is the No-Load power
requirement, which specifies the maximum ac power that may be used by a qualifying
external power supply in the No-Load condition. Maximum power consumption levels for No-
Load Mode are provided in Table 3, below.
Table 3: Energy Consumption Criteria for No Load
Nameplate Output Power (Pno)
Maximum Power in No-Load
0 to < 10 watts
<0.5 watts
> 10 to < 250 watts
< 0.75 watts
2. Tier 2: To continually recognize the most efficient models on the market and reflect
forthcoming improvements in technology, EPA plans to implement a Tier 2 No-Load Mode
specification. While subject to change based on analysis of new data, EPA believes that
0.3 watts (nameplate output power less than 10 watts) and 0.5 watts (nameplate output
power from 10 to 250 watts) represent reasonable Tier 2 targets for manufacturers.
Approximately one year before the Tier 2 effective date, EPA will: 1) collect efficiency data
(based on the ENERGY STAR Test Methodology) on a wide range of external power
supplies (varying in terms of size, efficiency, manufacturer, cost, and other parameters)
sold in markets throughout the world; 2) analyze the data to identify appropriate power
levels; 3) release the proposed Tier 2 specification for stakeholder review and comment
(focusing on the technical elements of Tier 2 and not on all programmatic details); and 4)
finalize the specification based on stakeholder comments. EPA has a target effective
date of January 1, 2008 for a Tier 2 specification.
4) Test Methodology
The specifics for testing the energy efficiency of an external power supply model are outlined in a
separate document titled "Test Method for Calculating the Energy Efficiency of Single-Voltage
External Ac-Dc and Ac-Ac Power Supplies (August 11, 2004)," which is available on the ENERGY
STAR Web site. The test results produced by this procedure shall be used to determine if a model
qualifies as ENERGY STAR. In addition, below are five ENERGY STAR-specific testing requirements.
A. Safety Standards: ENERGY STAR qualified external power supplies shall comply with applicable
safety standards from UL, CSA, and other global standards organizations. Relevant standards
include, but are not limited to:
UL 1012, Standard for Power Units Other Than Class 2, Edition 6, June 28, 1994
ENERGY STAR Program Requirements for External Power Supplies (Version 1.1)	4

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UL 1310, Standard for Class 2 Power Units, Edition 4, July 28, 1994
It is the Partner's responsibility to ensure that its products meet applicable local safety standards
based on where the product will be sold.
B.	Number of Units Required for Test: Testing shall be conducted by the manufacturer or its
authorized representative on three randomly chosen units of the same model. Manufacturers shall
report Active and No-Load Mode values for all three units as well as the average values. To
qualify as ENERGY STAR, all three units must meet the ENERGY STAR specification; only the
average values will be displayed on ENERGY STAR'S qualifying product list (see Section 4.E
below).
C.	Models Capable of Operating at Multiple Voltage/Frequency Combinations: Forswitchmode
power supplies capable of operating at multiple voltages and frequencies, testing shall be
conducted at both 115 volts @ 60 Hz and 230 volts @ 50 Hz, with the least efficient set of test
values used to determine if products qualify for the Active Mode and No-Load specifications.
D.	Multiple Tap or Switch Selectable Models: Manufacturers shall test a multiple tap or switch
selectable model at the highest and the lowest voltage outputs of the power supply. If the model
meets or exceeds the ENERGY STAR requirements at both the highest and the lowest voltage
outputs, then it qualifies as ENERGY STAR.
E.	Submittal of Qualified Product Data to EPA: Partners are required to self-certify those product
models that meet the ENERGY STAR guidelines and report information to EPA. ENERGY STAR
qualifying product lists, including information about new models as well as notification of
discontinued models, must be provided on a quarterly basis, or more frequently if desired by the
manufacturer. If no new models are introduced during a particular quarter, manufacturer should
notify EPA to ensure its partnership status is maintained.
5)	Effective Date: The date that manufacturers may begin to qualify and promote products as ENERGY
STAR will be defined as the effective date of the agreement. The Tier 1 ENERGY STAR single
voltage external ac-dc and ac-ac power supplies effective date is January 1, 2005. The target effective
date for Tier 2 requirements is January 1, 2008.
6)	Future Specification Revisions: EPA reserves the right to change the specification should
technological and/or market changes affect its usefulness to consumers, industry, or the environment.
In keeping with current policy, revisions to the specification are arrived at through stakeholder
discussions. In the event of a specification revision, please note that ENERGY STAR qualification is
not automatically granted for the life of a product model. To qualify as ENERGY STAR, a product
model must meet the ENERGY STAR specification in effect on the model's date of manufacture. The
date of manufacture is specific to each unit and is the date on which a unit is considered to be
completely assembled.
7)	International Efficiency Marking Protocol: ENERGY STAR partners shall follow the international
efficiency marking protocol to indicate the energy performance of their ENERGY STAR qualified
power supplies. (See Figure 1 for an illustration of the international efficiency mark.) In addition, the
efficiency level, as denoted by a Roman numeral under the protocol, shall be reported to EPA as part
of the qualified product data submission process. Further information about the endorsers of the
marking protocol and its intent is available at www.enenqvstar.gov/powersupplies.
ENERGY STAR partners shall clearly and permanently mark (e.g., imprint, label, etc.) the nameplate
of their qualifying external power supplies with the appropriate Roman numeral (I - VI) that
corresponds to specific minimum Active and No-Load efficiency levels. (See
www.energystar.gov/powersupplies and click on "International Efficiency Marking Protocol" for energy
performance requirements at each Roman numeral.) Partners shall determine the appropriate Roman
numeral by: 1) comparing the unit's Active and No-Load test data (when tested in accordance with the
ENERGY STAR Test Method and at each relevant test voltage and frequency value) with the
performance requirements at each level of the Roman numeral scale; and 2) choosing the highest
Roman numeral where the power supply meets the Active and No-Load requirements.
ENERGY STAR Program Requirements for External Power Supplies (Version 1.1)	5

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Figure 1: Illustration of International Efficiency Mark
Brand
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Information Technology Equipment,
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Non serviceable parts inside.
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INPUT :10»-240V—'M/WHz
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EFFICIENCY LEVELS ©
ABC CORP, AUSTRALIA
MADE IN
AUSTRALIA
When applied by a manufacturer, the mark shall conform to the following characteristics:
Format:	Roman numeral: I, II, III, IV, V, or VI.
Font:	Times Roman preferred (or other plain serif fonts).
Size:	Legible and indelible.
Color:	Text to contrast with the nameplate background.
Piacement: On the power supply nameplate; however, the exact location is at the discretion of the
manufacturer. The text "Efficiency Level" shown above is optional.
Example: Any external power supply meeting the performance requirements for level III and
above would qualify as ENERGY STAR. Power supplies with performance levels at I
or II would not qualify.
Partners shall begin to implement the international efficiency marking protocol no later than January 1,
2006.
ENERGY STAR Program Requirements for External Power Supplies (Version 1.1)

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