ENERGYSTAR
ENERGY STAR® Program Requirements
for Single Voltage External Ac-Dc and Ac-Ac Power Supplies
FINAL 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
4
4
4
6
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
8
9
ENERGY STAR Program Requirements for External Power Supplies - FINAL

-------
ENERGY STAR
ENERGY STAR® Program Requirements
for Single Voltage External Ac-Dc and Ac-Ac Power Supplies
Eligibility Criteria
Below is the product specification 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.
1) Definitions: 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. Consistent with this goal and the test
methodology, as described in Section 4, 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.
Please note the following products are temporarily excluded from this specification as outlined below:
Those power supplies with battery charging functions intended to recharge batteries that power:
1) flashlights; or 2) end-use products whose principal output is mechanical motion, the movement
of air, or the production of heat (e.g., power tools and rechargeable vacuums); or 3) detachable
batteries for use in the end-use products described in #1 and 2 above. (While it is difficult to
precisely delineate and categorize products in today's converging marketplace, in general this
exclusion applies to power tools and household appliances that produce heat, light, or motion. It
does not affect computer and consumer electronics, such as laptops, digital cameras, monitors,
CD players, cell phones, and cordless phones. Further, EPA recognizes that external power
supply manufacturers do not always know the exact end-use product their power supply will serve.
As such, this exclusion may only apply in those cases where the power supply and end-use
product are designed as a system and the intended end-use product is known by the power
supply designer.)
For brevity and consistency, these excluded products are hereafter referred to as excluded battery
charging systems.
The exclusion will be in place from January 1, 2005 through December 31, 2005. During this time,
EPA will work with stakeholders to further assess the appropriateness of the external power supply
test procedure for the products denoted in the exclusion. EPA will develop a second test procedure
and specification for the excluded battery charging systems, as necessary. If a battery charging
system test procedure and specification are not developed, the exclusion will expire on December 31,
2005 and battery charging systems will be covered by this ENERGY STAR specification under the
broad external power supply definitions found in Sections 1 .A and 1 .B below.
Note: The language above explicitly excludes battery charging systems typically found in
household appliances so that EPA can investigate them further and, as necessary, develop a test
method and specification that will best capture their energy savings opportunities. An exclusion
is being implemented so as to allow for additional research and test procedure
development while not delaying the introduction of the overall external power supply
specification.
Below is a general list of the excluded product categories:
•	Portable, rechargeable personal care appliances (e.g., shavers, toothbrushes, massagers)
•	Portable, rechargeable motorized kitchen appliances (e.g., blenders, can openers, electric
knives, kitchen cleaning brushes)
•	Portable, rechargeable floor care products (e.g., handheld vacuum cleaners, stick vacuums)
•	Portable, rechargeable power tools (e.g., drills, screwdrivers)
As always, manufacturers are strongly encouraged to contact EPA with questions or uncertainties
about ENERGY STAR eligibility.
ENERGY STAR Program Requirements for External Power Supplies - FINAL	2

-------
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
this specification); and
h)	has nameplate output power less than or equal to 250 watts.
Note: To complement the definitions above, EPA has attached a flowchart to graphically depict
the scope of the specification and test methodology.
External power supplies are often referred to as "adapters" and/or "chargers" in marketing
literature and trade publications. EPA's ac-dc and ac-ac definitions are intended to cover many of
these adapters and chargers, except where explicitly excluded on page 2 of these Eligibility
Criteria.
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.
1 "Physical enclosure" refers to the housing of the products themselves, not their retail packaging.
ENERGY STAR Program Requirements for External Power Supplies - FINAL

-------
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)] + 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%.
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 (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 - FINAL	4

-------
Note: As a voluntary program committed to recognizing the more efficient products on the market,
ENERGY STAR does not expect all external power supplies to meet the specification and strives
to recognize approximately the top 25 percent. EPA understands that it takes time to redesign
models to meet energy-efficiency specifications, safety standards, and other requirements. As
such, manufacturers may voluntarily introduce qualifying external power supplies at any time
during the life of the ENERGY STAR agreement and are not required to have qualifying models on
the specification's effective date.
As background and in response to one stakeholder question, EPA has defined efficiency as the
useful ac or dc output power provided by a power supply based on its total ac input power. By
basing its specification on nameplate output power, EPA uses readily available data (on the UL
label) that can be easily verified.
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 on July 1, 2006. 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 the top
25 percent in terms of energy 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 by late 2005 so partners have
adequate time to transition to the new levels.
Note: Regarding Tier 2 Active Mode, please note the following:
•	For existing ENERGY STAR end-use product categories (e.g., Telephony, Audio/DVD, Set-top
Boxes, Imaging, Computers/Laptops, Monitors, Water Coolers, etc.) the new external power
supply specification (Tiers 1 and 2) will be phased in as an additional eligibility requirement (i.e.,
end-use products must incorporate an ENERGY STAR qualified external power supply), where
appropriate, and when those specifications are revised. Once the external power supply
requirement is added, end-use product manufacturers must meet the external power supply
specification (e.g., Tier 1 or 2) in effect at that time. For some end-use products, depending on
the specification revision schedule, EPA may transition directly to specifying compliance with
the Tier 2 power supply levels after the Tier 2 specification goes into effect. (In addition, see
note in Section 5, Effective Date.)
•	To the extent that cost data is available or provided by stakeholders, EPA will consider the costs
associated with higher efficiency power supplies when developing the Tier 2 specification.
Consistent with the ENERGY STAR guiding principles, EPA strives to set specifications that can
be cost effectively achieved by several manufacturers. If ENERGY STAR qualifying models
have a higher purchase price than conventional models, consumer investments in increased
energy efficiency should be recoverable within a reasonable time period.
•	During the ENERGY STAR product qualification process, EPA will ask manufacturers to
indicate whether their qualifying power supplies use power factor correction (PFC). This
information will be analyzed to see what impact PFC has on the power supply's power
consumption and whether any special allowances for power supplies with PFC are needed
under the Tier 2 performance levels (for both Active and No-Load).
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.
ENERGY STAR Program Requirements for External Power Supplies - FINAL	5

-------
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
Note: EPA believes that the 0.5-watt and 0.75-watt specification levels are based on the best
available information to date. EPA may need to further evaluate the Tier 1 No-Load levels in the
future, particularly where nameplate output power is greater than 100 watts, pending the submittal of
test data and market research from interested stakeholders.
Executive Order 13221 requires federal agencies to purchase where possible end-use products that
use minimal standby power. Employing an ENERGY STAR qualified external power supply in end-
use product designs will help end-use product manufacturers to achieve low standby power
consumption. Please note, however, that use of an ENERGY STAR qualified external power supply
will not automatically or solely ensure compliance with the Executive Order, as it is based on the
standby power consumption of the product system (the power supply and all other components).
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 on July 1, 2006. 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 the top 25 percent in terms of energy
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 by late 2005 so partners have adequate time to transition to the new
levels.
Note: In recognition of stakeholder support for a 0.3-watt specification and given EPA's interest in
harmonizing with other international specifications, EPA is strongly considering a Tier 2 No-Load
level of less than or equal to 0.3 watts for the less than 10-watt external power supply category and
less than or equal to 0.5 watts for the 10-watt and greater products. Any measurement accuracy
issues associated with a 0.3-watt level will be considered and analyzed during the Tier 2
development process.
Please see note on page 5 regarding Tier 2 Active Mode. All information provided in that note also
applies to Tier 2 No-Load Mode.
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.
Note: For a copy of the revised test methodology, visit www.enenavstar.gov/powersuppliesdevelopment.
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
UL 1310, Standard for Class 2 Power Units, Edition 4, July 28, 1994
ENERGY STAR Program Requirements for External Power Supplies - FINAL	6

-------
It is the Partner's responsibility to ensure that its products meet applicable local safety standards
based on where the product will be sold.
Note: Section 4. A conveys ENERGY STAR'S guiding principle that product quality and safety
should never be compromised for energy efficiency. Rather than list all potentially applicable
safety standards, EPA has incorporated them by general reference in the text above.
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).
Note: Testing to determine ENERGY STAR qualification may be conducted by the manufacturer
or by its authorized representative, such as an independent testing laboratory. Manufacturers
must then attest to EPA (i.e., self-certify) that their product model meets the ENERGY STAR
guidelines (i.e., EPA does not individually test each model).
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.
Note: This ENERGY STAR specification requires switchmode power supplies capable of
operating at multiple voltages and frequencies to be tested at both 115 volts and 230 volts.
ENERGY STAR qualifying external power supplies will be sold into a global marketplace and will
be used in numerous countries by international travelers. By qualifying models under the least
efficient set of test values, this approach ensures that models meet the ENERGY STAR
performance levels in multiple markets and mitigates any potential variations in tested values
across markets.
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 second phase
of the specification, Tier 2, shall commence on July 1, 2006.
ENERGY STAR Program Requirements for External Power Supplies - FINAL

-------
Note: EPA is making plans to promote ENERGY STAR for External Power Supplies at several
upcoming industry events, including the 2005 Consumer Electronics Show (CES) and the Applied
Power Electronics Conference and Exposition (APEC) 2005. Interested manufacturers are
encouraged to start testing their external power supplies, so they can join ENERGY STAR and
qualify their energy-efficient models once the specification is finalized. Participating manufacturers
and their ENERGY STAR qualified models will be featured/promoted at both events.
Finally, for existing ENERGY STAR end-use product categories (e.g., Telephony, Audio/DVD,
Set-top Boxes, Imaging, Computers/Laptops, Monitors, Water Coolers, etc.) the new external
power supply specification will be phased in as an additional eligibility requirement (i.e., end-use
products must incorporate an ENERGY STAR qualified external power supply), where
appropriate, and when those specifications are revised. The implementation date for the new
external power supply requirement may be different for each applicable end-use product category
(based on its product design/manufacturing cycles and specification revision process) and as
always, will be informed by stakeholder comments and discussions. Please note that the first
product category to incorporate the external power supply specification will be Telephony
(cordless phones, answering machines, and combination units).
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.enenavstar.gov/powersuppliesdevelopment.
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.enerqvstar.gov/powersuppliesdevelopment 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 - FINAL

-------
Figure 1: Illustration of international Efficiency Mark

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 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 - FINAL

-------
Note: The international efficiency marking protocol will provide a system for power supply
manufacturers to designate the minimum efficiency performance of an external power supply, so
that finished product manufacturers and government representatives can easily determine a unit's
efficiency. This mark will not serve as a consumer information label, but rather will demonstrate
the performance of the external power supply when tested to the internationally supported test
method (i.e., the test method referenced in Section 4 of this document). The international
efficiency mark will consist of a Roman numeral (I - VI) that corresponds to specific minimum
Active and No-Load efficiency levels and will be printed/applied by the manufacturer on the
external power supply nameplate (exact location will be left to the manufacturer's discretion).
Given that external power supplies are a globally manufactured and marketed product, EPA has
coordinated with representatives in China, Australia, and other countries throughout the ENERGY
STAR specification development process. This international efficiency marking protocol will
provide further opportunities for coordination as the specification is finalized and implemented in
the marketplace. The benefits for manufacturers include:
•	The marking system will be adopted and recognized around the world. As such, power supply
manufacturers will not have to use different marks for each market into which they sell their
products.
•	The mark will not require much space on the nameplate and was intentionally selected to avoid
confusion with other non-energy related markings that already appear on external power
supplies.
This requirement, which was introduced late in the specification development process, will take
effect on January 1, 2006.
ENERGY STAR Program Requirements for External Power Supplies - FINAL
10

-------