ENERGY STAR
ENERGY STAR® Program Requirements
for Single Voltage External Ac-Dc and Ac-Ac Power Supplies
Eligibility Criteria (Version 2.0)
Final
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: Standard Models
Table 2: Energy-Efficiency Criteria for Active Mode: Low Voltage Models
Table 3: Examples of Minimum Average Efficiency in Active Mode
Table 4: Energy Consumption Criteria for No-Load
Section 4: Test Methodology
Section 5: Effective Date
Section 6: Effective Date for ENERGY STAR Product Specifications
Table 5: Version 1.1 Energy-Efficiency Criteria for Active Mode
Table 6: Version 1.1 Energy Consumption Criteria for No-Load
Section 7: Future Specification Revisions
Section 8: International Efficiency Marking Protocol
Figure 1: Illustration of International Efficiency Mark
Final ENERGY STAR Program Requirements for External Power Supplies (Version 2.0)
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ENERGY STAR® Program Requirements
for Single Voltage External Ac-Dc and Ac-Ac Power Supplies
Eligibility Criteria (Version 2.0)
Final
Below is the product specification (Version 2.0) for ENERGY STAR qualified single voltage external ac-ac
and ac-dc power supplies. A product must meet all of the identified criteria if it is to be qualified as
ENERGY STAR by its manufacturer.
The goal of this ENERGY STAR external power supply specification is to recognize those models with an
efficient ac-ac or ac-dc 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.enerqvstar.gov/products) 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-ac and ac-dc power
supplies and other related terms as relevant to ENERGY STAR.
A.	External Power Supply (EPS): For the purposes of this specification, an external power supply:
a)	is designed to convert line voltage ac input into lower voltage ac or dc output;
b)	is able to convert to only one 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.	Ac-Ac External Power Supply: An external ac-ac power supply is an EPS designed to convert line
voltage ac input into lower voltage ac output.
C.	Ac-Dc External Power Supply: An external ac-dc power supply is an EPS designed to convert line
voltage ac input into lower voltage dc output.
D.	Low Voltage External Power Supply: For the purposes of this specification, a low voltage model is
an EPS with a nameplate output voltage of less than 6 volts and a nameplate output current
greater than or equal to 550 milliamps.
E.	Model: An EPS that is sold or marketed under a unique model number or marketing name. Any
variation in the nameplate information (e.g., the rated input or output voltage, amperage, or
wattage), circuitry, or output cord size is considered a unique model.
1 "Physical enclosure" refers to the housing of the products themselves, not their retail packaging.
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F.	Active Mode: The condition in which the input of a power supply is connected to line voltage ac
and the output is connected to an ac or a dc load drawing a fraction of the power supply's
nameplate power output greater than zero.
G.	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.
H.	Power Factor (True'): The true power factor is the ratio of the active, or real, power (P) consumed
in watts to the apparent power (S), drawn in volt-amperes (VA).
PF = £-
11 s
This definition of power factor includes the effect of both distortion and displacement.
2)	Qualifying Products: In order to qualify as ENERGY STAR, an external power supply model must
meet the definition in Section 1 .A, as well as either the definition in 1 .B or 1 .C, and the specification
requirements provided in Section 3, below.
3)	Energy-Efficiency Specifications for Qualifying Products: Only those products in Section 2 that
meet M of the following criteria for Active Mode, No-Load Mode, and power factor (if applicable) may
qualify as ENERGY STAR.
A. Active Mode
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. Tables 1 and 2, below, outline the equations for determining minimum
average efficiency, where Pno stands for nameplate output power and Ln refers to the natural
logarithm. Table 1 addresses all standard EPSs, while Table 2 gives separate equations for a
subset of low voltage EPSs that meet the appropriate definition in Section 1 .D. All efficiency
values shall be expressed in decimal form and rounded to the hundredths place.
Table 1: Energy-Efficiency Criteria for Ac-Ac and Ac-Dc External Power Supplies in Active
Mode: Standard Models
Nameplate Output Power (Pno)
Minimum Average Efficiency in Active
Mode (expressed as a decimal)2
0 to < 1 watt
>0.480* Pno + 0.140
> 1 to < 49 watts
> [0.0626 * Ln (Pno)] + 0.622
> 49 watts
> 0.870
Table 2: Energy-Efficiency Criteria for Ac-Ac and Ac-Dc External Power Supplies
Nameplate Output Power (Pno)
Minimum Average Efficiency in Active
Mode (expressed as a decimal)2
0 to < 1 watt
> 0.497 * Pno + 0.067
> 1 to < 49 watts
> [0.0750 * Ln (Pno)] + 0.561
> 49 watts
> 0.860
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 0.0626 (or 0.0750 for low voltage models), with the resulting
output added to 0.622 (or 0.561 for low voltage models), (b) An efficiency of 0.87 or 0.86 in decimal form
corresponds to the more familiar value of 87% or 86% when expressed as a percentage.
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Examples to Illustrate the Active Mode Approach: Average Active Mode efficiency and
ENERGY STAR qualification shall be determined as follows:
Determine whether the product meets the definition for low voltage products by comparing the
nameplate output voltage and nameplate output current to the definition found in Section 1 .D.
Calculate the model's single average Active Mode efficiency for each test voltage 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 found in Section 4.
Based on the model's nameplate output power, select the appropriate equation from Table 1
or 2 and calculate the minimum average efficiency required by ENERGY STAR.
Compare the model's actual average efficiency to the minimum average efficiency required by
ENERGY STAR. If the 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 and Table 2, the minimum average efficiencies
required of six sample power supplies are provided in Table 3, below. Power supplies 1 through 6
would meet the ENERGY STAR Active Mode requirement if they had average efficiencies greater
than or equal to the corresponding values shown in the far right column. Therefore, if Power
Supply 3 in Table 3 had an actual average efficiency of 80%, it would satisfy the Active Mode
requirement because it surpassed the ENERGY STAR minimum average efficiency of 79%.
Table 3: Examples of Minimum Average Efficiency in Active Mode
Sample
Nameplate
Output
Power (Pno)
Nameplate
Output
Voltage
Nameplate
Output
Current
Average Efficiency in Active Mode
(expressed as a decimal)
PS 1
0.75 watts
1V
750 mA
0.497 * 0.75 + 0.067 = 0.4398 or 0.44
PS 2
0.75 watts
10V
75 mA
0.480 * 0.75 + 0.140 = 0.5000 or 0.50
PS 3
20 watts
5V
4000 mA
[0.0750 * Ln (20)] + 0.561 = 0.7857 or 0.79
PS 4
20 watts
10V
2000 mA
[0.0626 * Ln (20)] + 0.622 = 0.8095 or 0.81
PS 5
75 watts
5V
15000 mA
0.86
PS 6
75 watts
10V
7500 mA
0.87
B. Power Factor Correction (PFQ
In addition to the Active Mode efficiency requirements found above, power supplies with greater
than or equal to 100 watts input power must have a true power factor of 0.9 or greater at 100% of
rated load when tested at 115 volts @ 60Hz.
Note: In the most recent round of comments, several stakeholders noted that power factor losses are less
significant at 230 volts, because with half the current, the conduction losses are one-quarter of what they
would be at 115 volts. Stakeholders also noted that EPS units meeting a 0.9 power factor at 115 volts will
also generally have a high power factor at 230 volts (although slightly lower than 0.9 in some cases).
Further, products sold in Europe must already meet the requirements for harmonic currents (EN 61000-3-
2), and thus are effectively covered for power quality at 230 volts.
In addition, other manufacturers have noted that the 0.9 power factor requirement at 230 volts could
eliminate the single stage PFC architecture, which is a cost effective approach to designing efficient EPSs
with improved power quality. While a dual stage PFC architecture is capable of meeting a 0.9 power factor
requirement at 230 volts, it is a more resource intensive design and may lead to decreases in Active Mode
efficiency.
For these reasons, EPA has revised the final power factor requirement to only apply to testing at 115 volts,
with no power factor requirement at 230 volts. Products designed to operate at both 115 volts and 230
volts must meet the power factor requirement when tested at 115 volts, but not when tested at 230 volts.
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C. No-Load Mode
The third element of the ENERGY STAR specification is the No-Load power requirement, which
specifies the maximum ac power that may be used by a qualifying ac-ac external power supply or
ac-dc external power supply in the No-Load condition. Maximum power consumption levels for
No-Load Mode are provided in Table 4, below.
Table 4: Energy Consumption Criteria for No-Load
Nameplate Output
Power (Pno)
Maximum Power in No-Load
Ac-Ac EPS
Ac-Dc EPS
0 to < 50 watts
<0.5 watts
<0.3 watts
> 50 to < 250 watts
<0.5 watts
<0.5 watts
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 7, April 29, 2005
UL 1310, Standard for Class 2 Power Units, Edition 5, May 3, 2005
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
measure and maintain the Active Mode, No-Load Mode, and power factor values (if applicable) 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, No-Load Mode, and power factor
(only applicable at 115 volts @ 60 Hz) 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.
All unique EPS models, as defined in Section 1 .E, must be separately tested and reported for
ENERGY STAR qualification. However, in some cases, a partner may have a base model number
Final ENERGY STAR Program Requirements for External Power Supplies (Version 2.0)	5

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with several extensions to reflect various input pin and output connector configurations. If the only
variation between the models is the physical connector configuration (provided that the nameplate
information, circuit design, and output cord length and gauge are the same), partners may test
one representative model and qualify it using a generic "XX" designation for the extension in the
model number.
When qualifying EPSs as ENERGY STAR, partners also have the option of qualifying a family of
EPSs that all meet the ENERGY STAR requirements, rather than individually submitting each
model. For ENERGY STAR'S purposes, an EPS model family is defined as a group of
switching-mode external power supplies that feature the same design (e.g., circuitry and
components), transformer, and output wattage, but differ in rated output voltage. To qualify
a model family, partners must provide the efficiency data (average of three test units) for the
highest and lowest output voltage members of the EPS model family that meet the ENERGY
STAR specification. When submitting model families, manufacturers continue to be held
accountable for any efficiency claims made about their external power supply products. In other
words, even though data may not be submitted to ENERGY STAR on each model, manufacturers
are still responsible for ensuring (and if challenged by another party, defending) each model's
compliance with ENERGY STAR within the model family.
5) Effective Date for EPS Manufacturers: The ENERGY STAR single voltage external ac-ac and ac-dc
power supplies specification (Version 2.0) effective date is November 1, 2008. Any previously
executed agreement on the subject of ENERGY STAR qualified EPSs shall be terminated effective
October 31, 2008.
Note: The following sentence has been removed in the Final specification: "The date that manufacturers
may begin to promote products as ENERGY STAR under Version 2.0 will be defined as the effective date
of the agreement." Because products that meet Version 2.0 also meet the ENERGY STAR specification in
effect (Version 1.1) prior to November 1, 2008, EPA agrees that manufacturers may begin qualifying and
promoting their Version 2.0 products as ENERGY STAR prior to its effective date.
A. Product Qualification under Version 2.0: Prior to November 1, 2008, EPA will begin accepting
product qualifications under Version 2.0 through the ENERGY STAR online product submittal
system. All products, including models originally qualified under Version 1.1, with a date of
manufacture on or after November 1, 2008 must meet the new Version 2.0 requirements in order
to qualify as ENERGY STAR. The date of manufacture is specific to each unit and is the date
(e.g., month and year) on which a unit is considered to be completely assembled.
6) Effective Date for ENERGY STAR Product Specifications
A. Computer and Imaging Equipment Specifications: To qualify as ENERGY STAR under the
Computer Version 4.0 Tier 1 and Imaging Equipment Version 1.0 Tier 1 specifications, computers
and imaging equipment with an EPS must meet the following requirements as provided in Tables
5 and 6. These requirements are identical to the EPS Version 1.1 specification, which was in
effect upon completion and implementation of the Computer and Imaging Tier 1 specifications,
and do not include a power factor requirement as specified in this Version 2.0 specification.
Computers qualified under the Version 5.0 specifications (effective July 2009) and Imaging
Equipment qualified under the Version 1.1 Tier 2 specifications (effective April 2009) will
need to meet the EPS Version 2.0 requirements, regardless of the EPS's date of
manufacture. Refer to Section 3, Energy-Efficiency Specifications for Qualifying Products,
of this document for the detailed Version 2.0 EPS requirements.
Note: Two changes have been made to Section 6.A, above. The first change was to update the
reference to the latest Computer specification from Version 4.0 Tier 2 to Version 5.0 and similarly to
change the reference to the latest Imaging Equipment specifications from Version 1.0 Tier 2 to
Version 1.1 Tier 2. The second change was to clarify that once the latest Computer (Version 5.0) and
Imaging Equipment (Version 1.1 Tier 2) specifications take effect, qualifying models with an EPS must
include an EPS that meets the EPS Version 2.0 requirements, even if the EPS manufacture date is
prior to July 2009 or April 2009, respectively.
Final ENERGY STAR Program Requirements for External Power Supplies (Version 2.0)	6

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• Computers and Imaging Equipment products that make use of an EPS must ensure that their
EPS meets or exceeds a minimum average efficiency for Active Mode, which varies based on
the model's nameplate output power. The following table 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 5: Version 1.1 Energy-Efficiency Criteria for Ac-Ac and Ac-Dc External Power Supplies in
Active Mode
Nameplate Output Power (Pno)
Minimum Average Efficiency in Active
Mode (expressed as a decimal)
0 to < 1 watt
> 0.49 * Pno
> 1 to < 49 watts
> [0.09 * Ln (Pno)] + 0.49
> 49 watts
>0.84
• External Power Supplies must meet a 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 the table
below.
Table 6: Version 1.1 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
B. Primarily Portable Products with Qualified EPSs: To qualify as ENERGY STAR, the EPS
associated with primarily portable products that are not otherwise covered by the ENERGY STAR
program (e.g., mobile phones, MP3 speaker systems, water filtration systems) must meet the EPS
Version 2.0 specification as of its November 1, 2008 effective date, as outlined in Section 5,
above. Visit http://www.enerqystar.qov/index.cfm?c=ext power supplies pd.CE manufacturers
for more information about this product category.
Note: Based on stakeholder feedback, EPA has extended the effective date for Primarily Portable
Products with Qualified EPSs from July 1 to November 1, 2008. This change provides interested
partners with additional time to begin including Version 2.0 EPSs in their end-use product designs and
also simplifies the specification overall by aligning effective dates.
C. Other Electronic Product Specifications: EPA is committed to advancing power supply efficiency in
all products as quickly as is reasonable. For Telephony, the EPSs are a central part of this
specification and thus must meet Version 2.0 as of its effective date of November 1, 2008, as
outlined in Section 5, above. For Monitors, Televisions, Set-top Boxes, and Audio/DVD, updated
specifications will specifically require that any EPSs meet the Version 2.0 requirements.
Manufacturers should refer to the latest electronic product category specification for relevant
effective dates.
7)	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.
8)	International Efficiency Marking Protocol: ENERGY STAR partners shall follow the international
efficiency marking protocol to indicate the energy performance of their ENERGY STAR qualified
Final ENERGY STAR Program Requirements for External Power Supplies (Version 2.0)	7

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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 will be available at www.enerqvstar.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 and power factor requirements
(where applicable). (See www.enerqvstar.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, No-Load, and power
factor 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, No-Load, and power factor (where applicable) requirements.
Note: EPA updated the International Efficiency Marking Protocol text above to address power factor
requirements, where applicable, given that power factor is one of the performance criteria covered
under the ENERGY STAR Version 2.0 EPS specification.
The Protocol will be amended with the new requirements for level V and only EPSs with level V
efficiency levels will qualify as ENERGY STAR. In addition, EPA plans to include updated information
about the marking protocol on its ENERGY STAR Web site in the near future.
Figure 1: Illustration of International Efficiency Mark
Brand
BATTERY CHARGER for use with
Information Technology Equipment
AWARNING
For u*e with	rechargeable
Li-ion Battery Pack EN-ELI.
Non serviceable parts inside.
<• (( ©N999
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OUTPUU.4VmO.IA
EFFICIENCY LEVEL,©	WADE IN
ABC CORP., AUSTRALIA	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.
Placement: 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 V and
above would qualify as ENERGY STAR (Version 2.0). Power supplies with
performance levels of I - IV would not qualify under the Version 2.0 specification.
Final ENERGY STAR Program Requirements for External Power Supplies (Version 2.0)

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