ENERGYSTAR
ENERGY STAR® Program Requirements
for Single Voltage External Ac-Dc and Ac-Ac Power Supplies
Eligibility Criteria (Version 2.0)
Draft 1
Table of Contents
Section 1: Definitions	2
Section 2: Qualifying Products	3
Section 3: Energy-Efficiency Specifications for Qualifying Products	3
Table 1: Energy-Efficiency Criteria for Active Mode	3
Table 2: Examples of Minimum Average Efficiency in Active Mode	4
Table 3: Energy Consumption Criteria for No-Load	5
Section 4: Test Methodology	5
Section 5: Effective Date	6
Section 6: Future Specification Revisions	6
Section 7: International Efficiency Marking Protocol	6
Figure 1: Illustration of International Efficiency Mark	7
Draft 1 ENERGY STAR Program Requirements for External Power Supplies (Version 2.0)

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ERGYSTA
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ENERGY STAR® Program Requirements
for Single Voltage External Ac-Dc and Ac-Ac Power Supplies
Eligibility Criteria (Version 2.0)
Draft 1
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Below is the Draft 1 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;
is able to convert to only one output voltage at a time;
is sold with, or intended to be used with, a separate end-use product that constitutes the
primary load;
is contained in a separate physical enclosure1 from the end-use product;
is connected to the end-use product via a removable or hard-wired male/female electrical
connection, cable, cord or other wiring;
does not have batteries or battery packs that physically attach directly (including those
that are removable) to the power supply unit;
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
has nameplate output power less than or equal to 250 watts.
b)
c)
d)
e)
f)
g)
h)
Note: EPA has consolidated the characteristics shared by external power supplies into a single
EPS definition to improve the readability of the Definitions section. Specific definitions for ac-ac
and ac-dc power supply types are included below.
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.	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.
"Physical enclosure" refers to the housing of the products themselves, not their retail packaging.
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55	E. No-Load Mode: The condition in which the input of a power supply is connected to an ac source
56	consistent with the power supply's nameplate ac voltage, but the output is not connected to a
57	product or any other load.
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59	F. Power Factor (True'): The true power factor is the ratio of the active, or real, power (P) consumed
60	in watts to the apparent power (S), drawn in volt-amperes (VA).
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70	2) Qualifying Products: In order to qualify as ENERGY STAR, an external power supply model must
71	meet the definition in Section 1.A, as well as either the definition in 1.B or 1.C, and the specification
72	requirements provided in Section 3, below.
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74	3) Energy-Efficiency Specifications for Qualifying Products: Only those products in Section 2 that
75	meet all of the following criteria for Active Mode, Power Factor, and No-Load Mode may qualify as
76	ENERGY STAR.
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78	A. Active Mode
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80	To be eligible for ENERGY STAR qualification, an external power supply model must meet or
81	exceed a minimum average efficiency for Active Mode, which varies based on the model's
82	nameplate output power. Table 1, below, outlines the equations for determining minimum average
83	efficiency, where Pno stands for nameplate output power and Ln refers to the natural logarithm.
84	Efficiency shall be expressed in decimal form and rounded to the hundredths place.
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86	Table 1: Energy-Efficiency Criteria for Ac-Ac and Ac-Dc External Power Supplies
87	in Active Mode
PF = £-
11 s
This definition of power factor includes the effect of both distortion and displacement.
Note: EPA has included a power factor definition to support the power factor requirements
included in the Draft 1 Version 2.0 specification.
Nameplate Output Power (Pno)
Minimum Average Efficiency in Active
Mode (expressed as a decimal)2
0 to < 1 watt
>0.44* Pno + 0.145
> 1 to < 36 watts
> [0.08 * Ln (Pno)] + 0.585
> 36 watts
> 0.870
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Note: EPA has developed proposed new Active Mode levels for the Version 2.0 specification from
a dataset of 1,834 units measured in 2006 or 2007 including: currently qualified ENERGY STAR
external power supplies; data shared with EPA from China's Standard Certification Center (CSC);
and a small set of new models purchased at US retail stores and tested on behalf of EPA. The
dataset includes both 230 volt data as well as 115 volt data and shows a compliance rate of 26%
for units meeting the Active Mode, No-Load and Power Factor requirements. While the current
dataset includes a preponderance of ENERGY STAR models, EPA does not feel that this biases
the analysis because: 1) Regulations in California, Australia, and potentially elsewhere will exceed
ENERGY STAR'S Tier 1 levels (Version 1.1 specification) as early as July 2008, making ENERGY
STAR models representative of the status quo and a good proxy for the US market in 2008; and
2) Beginning in June, EPA has invited interested manufacturers to submit data for non-ENERGY
STAR models for incorporation into the dataset; EPA encourages manufacturers to provide test
data for analysis along with their formal comments on this draft specification.
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 0.08, with the resulting output added to 0.585. (b) An efficiency
of 0.87 in decimal form corresponds to the more familiar value of 87% when expressed as a percentage.
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Note (cont.): The suggested Version 2.0 requirements follow the same form as the Version 1.1
requirements, with a sloped line below 1 watt, a log function for mid-wattage units, and a flat line
requirement above a certain wattage threshold. With these more stringent requirements, the
increased flat line limit of 0.87 (87%) begins earlier than the cutoff used in the Version 1.1
specification (at 36 watts instead of 49 watts). These tighter limits require an average efficiency
improvement of about 10 percentage points at the low end and 3 percentage points at the high end,
which EPA believes will garner significant savings from modest improvements of power supply design.
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 37%, 82%, and 87%, respectively. Therefore, if Power Supply 1 in Table 2
had an actual average efficiency of 40%, it would satisfy the Active Mode requirement because it
surpassed the ENERGY STAR minimum average efficiency of 37%.
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
0.44 * 0.5 + 0.145 = 0.365 or 0.37
Power Supply 2
20 watts
[0.08 * Ln (20)] + 0.585 = 0.82466 or 0.82
Power Supply 3
75 watts
0.87
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133	B. Power Factor Correction
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135	In addition to the Active Mode efficiency requirements found above, all qualifying power supplies
136	with a nameplate output power (Pno) of greater than or equal to 75 watts must have a true power
137	factor of 0.9 or greater when measured at 100% of rated output.
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154	The third element of the ENERGY STAR specification is the No-Load power requirement, which
155	specifies the maximum ac power that may be used by a qualifying ac-ac external power supply or
156	ac-dc external power supply in the No-Load condition. Maximum power consumption levels for
157	No-Load Mode are provided in Table 3, below.
Draft 1 ENERGY STAR Program Requirements for External Power Supplies (Version 2.0)	4
Note: In recent years, there has been increased interest from the international efficiency
community in decreasing the effect that high wattage products have on power quality. To this
end, EPA has included power factor requirements for high power devices. Power factor correction
helps to cut l-squared R losses in building distribution wiring significantly, yielding increased
savings in large buildings. For the purpose of this specification, all EPSs with a power output of at
least 75 watts will be required to have a power factor of at least 0.9 at 100% of rated load. This
75-watt cutoff coincides with the European regulation EN 61000-3-2, which went into effect in
2001 and requires limited total harmonic distortion for appliances above 75 watts input power. A
power factor of at least 0.9 at 100% of rated load is consistent with the internal power supply
requirement in the Version 4.0 ENERGY STAR Computer specification. At these levels,
approximately 90% of current ENERGY STAR qualified power supplies can meet this
requirement.
C. No-Load Mode

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Table 3: 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
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Note: Based on feedback from stakeholders regarding ac-ac design differences and data
submitted to ENERGY STAR, EPA is proposing separate No-Load requirements for ac-dc and ac-
ac models under the Version 2.0 specification in order to reflect the market and recognize
opportunities for increased savings. As ac-dc power supplies generally have lower No-Load
losses, EPA suggests tightening the No-Load requirement for low wattage ac-dc EPSs to 0.3
watts, while simultaneously increasing the low-wattage cutoff to 50 watts (from 10 watts in the
Version 1.1 specification). In addition, EPA proposes that ac-dc models above 50 watts meet the
more stringent No-Load level of less than or equal to 0.5 watts. Because available test data for
ac-ac power supplies indicates that they would have significant difficulty meeting the low-wattage
No-Load level of 0.3 watts, EPA has suggested a No-Load level of 0.5 watts for all eligible ac-ac
power supplies. All ac-ac power supplies in EPA's current dataset can meet this No-Load
requirement. EPA has received feedback that ac-ac external power supplies above 30 watts
should receive a less stringent No-Load requirement, but EPA has very little data on ac-ac
supplies over even 15 watts to support this claim. Manufacturers with high wattage ac-ac external
power supplies are encouraged to submit relevant data on these products for EPA's analysis.
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, Power Factor, 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, Power Factor, and No-Load
specifications.
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224	D. Multiple Tap or Switch Selectable Models: Manufacturers shall test a multiple tap or switch
225	selectable model at the highest and the lowest voltage outputs of the power supply. If the model
226	meets or exceeds the ENERGY STAR requirements at both the highest and the lowest voltage
227	outputs, then it qualifies as ENERGY STAR.
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229	E. Submittal of Qualified Product Data to EPA: Partners are required to self-certify those product
230	models that meet the ENERGY STAR guidelines and report information to EPA. ENERGY STAR
231	qualifying product lists, including information about new models as well as notification of
232	discontinued models, must be provided on a quarterly basis, or more frequently if desired by the
233	manufacturer. If no new models are introduced during a particular quarter, manufacturer should
234	notify EPA to ensure its partnership status is maintained.
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236	5) Effective Date: The date that manufacturers may begin to qualify and promote products as ENERGY
237	STAR will be defined as the effective date of the agreement. The ENERGY STAR single voltage
238	external ac-ac and ac-dc power supplies (Version 2.0) effective date is July 1, 2008.
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240	Note: EPA is proposing that the EPS Version 2.0 specification take effect for EPS manufacturers
241	on July 1, 2008. After this specification takes effect, all EPSs marketed as ENERGY STAR must
242	meet the Version 2.0 levels.
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244	Revisions to the EPS specification will have implications for ENERGY STAR specifications for
245	several electronic product categories (i.e., computers, monitors, imaging, televisions, telephony,
246	set-top boxes, and audio/DVD). EPA is committed to advancing power supply efficiency in all
247	products as quickly as is reasonable. Please refer to EPA's letter dated October 11, 2007, which
248	accompanies this draft specification, for details.
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251	6) Future Specification Revisions: EPA reserves the right to change the specification should
252	technological and/or market changes affect its usefulness to consumers, industry, or the environment.
253	In keeping with current policy, revisions to the specification are arrived at through stakeholder
254	discussions. In the event of a specification revision, please note that ENERGY STAR qualification is
255	not automatically granted for the life of a product model. To qualify as ENERGY STAR, a product
256	model must meet the ENERGY STAR specification in effect on the model's date of manufacture. The
257	date of manufacture is specific to each unit and is the date on which a unit is considered to be
258	completely assembled.
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260	7) International Efficiency Marking Protocol: ENERGY STAR partners shall follow the international
261	efficiency marking protocol to indicate the energy performance of their ENERGY STAR qualified
262	power supplies. (See Figure 1 for an illustration of the international efficiency mark.) In addition, the
263	efficiency level, as denoted by a Roman numeral under the protocol, shall be reported to EPA as part
264	of the qualified product data submission process. Further information about the endorsers of the
265	marking protocol and its intent is available at www.enenavstar.gov/powersupplies.
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267	ENERGY STAR partners shall clearly and permanently mark (e.g., imprint, label, etc.) the nameplate
Draft 1 ENERGY STAR Program Requirements for External Power Supplies (Version 2.0)	6
Note: As background, it is important to note that 115 volts @ 60 Hz and 230 volts @ 50 Hz were
specifically selected during test procedure development in order to balance the need to reflect the
multiple combinations of voltage and frequency found in global markets with a desire to minimize the
testing burden for participating manufacturers. The 115 volts @ 60 Hz combination was selected
because the United States provides a nominal voltage of 120 volts and Japan provides 110 volts. The
other test point is specified at 230 volts @ 50 Hz because 230 volts represents the average between
the voltages used by Europe (240 volts) and the United Kingdom and China (both at 220 volts).
Recently, one stakeholder has suggested to EPA that manufacturers have the option of voluntarily
providing additional measurement data at 100 volts @ 50/60 Hz if destined for the Japanese
marketplace. ENERGY STAR qualification would still be determined based on the guidelines provided
in Section 4.C above (i.e., models could not qualify based solely on test data at 100 volts @ 50/60
Hz). EPA is willing to consider input from industry on this proposal, but would need to see evidence
that the benefits outweigh the additional administrative costs for both EPA and its partners.

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268	of their qualifying external power supplies with the appropriate Roman numeral (I - VI) that
269	corresponds to specific minimum Active and No-Load efficiency levels. (See
270	www.enerqvstar.ciov/powersupplies and click on "International Efficiency Marking Protocol" for energy
271	performance requirements at each Roman numeral.) Partners shall determine the appropriate Roman
272	numeral by: 1) comparing the unit's Active and No-Load test data (when tested in accordance with the
273	ENERGY STAR Test Method and at each relevant test voltage and frequency value) with the
274	performance requirements at each level of the Roman numeral scale; and 2) choosing the highest
275	Roman numeral where the power supply meets the Active and No-Load requirements.
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280	Figure 1: Illustration of International Efficiency Mark
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BATTERY CHARGER for use with
Information Technology Equipment
^WARNING
For uee with	rechargeable
LHon Battery Pack EN-ELI.
Non serviceable parte inside
( £ ©N999
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EFFICIENCY LEVEL.® 	
ABC CORP., AUSTRALIA AUSTRALIA
When applied by a manufacturer, the mark shall conform to the following characteristics:
Format:
Font:
Size:
Color:
Placement:
Example:
Roman numeral: I, II, III, IV, V, or VI.
Times Roman preferred (or other plain serif fonts).
Legible and indelible.
Text to contrast with the namepiate background.
On the power supply namepiate; however, the exact location is at the discretion of the
manufacturer. The text "Efficiency Level" shown above is optional.
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.
Note: The international community has reserved level V of the international efficiency marking
protocol for ENERGY STAR'S Version 2.0 specification. Once the Version 2.0 specification is
finalized, 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.
Draft 1 ENERGY STAR Program Requirements for External Power Supplies (Version 2.0)

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