You are here

Covered Product Category: Uninterruptible Power Supplies (for Data Center, Computer, and Telecommunication Applications)

The Federal Energy Management Program (FEMP) provides acquisition guidance for uninterruptible power supplies (UPS), a product category covered by the ENERGY STAR program. Federal laws and requirements mandate that agencies purchase ENERGY STAR-qualified products in all product categories covered by this program and any acquisition actions that are not specifically exempted by law.


The U.S. Environmental Protection Agency (EPA) sets the efficiency criteria for this product category in its ENERGY STAR program requirements. Manufacturers meeting these requirements are allowed to display the ENERGY STAR label on complying models. Visit the ENERGY STAR website for the most up-to-date UPS efficiency levels and product specification information, and a list of qualified products.


This acquisition guidance and associated ENERGY STAR program requirements apply to UPS products intended for use in consumer, commercial, telecommunications (DC-output), and data center applications. UPS products that are internal to computers or other electronic devices; designed for industrial applications; are part of an electric transmission or distribution system; used in mobile (e.g., marine, airborne) applications; or are part of a cable television network are excluded.

The federal supply sources for UPSs are the General Services Administration (GSA) and Defense Logistics Agency (DLA). GSA sells UPSs through its Multiple Awards Schedules program and online shopping network, GSA Advantage! DLA sells them through its online supply network, DOD EMALL.

The United Nations Standard Products and Services Code (UNSPSC) is a worldwide classification system for eCommerce. It contains over 50,000 commodities, including many used in the federal sector, each having a unique eight-digit, four-level identification code. Using the UNSPSCs will assist federal buyers with identifying covered product categories and improve record keeping. The UNSPSC for UPSs is 39121011.


FEMP has calculated that a 2,700-watt voltage independent (VI) UPS meeting the minimum ENERGY STAR efficiency requirement will save money if priced no more than $130 above the less efficient alternative. The best available product saves even more: $200. The complete cost-effectiveness example is provided in Table 1.

Performancea Best Availableb ENERGY STAR Required Less Efficient
Average Efficiency 98.4% 96.7% 93.5%
Annual Energy Use 6,010 kWh/year 6,180 kWh/year 6,500 kWh/year
Annual Energy Cost $540 $556 $585
Lifetime Energy Cost $2,390 $2,460 $2,590
Lifetime Energy Cost Savings $200 $130 ======
a Based on the following assumptions: Annual energy use is based on the AC-output loading assumptions contained in the ENERGY STAR UPS eligibility criteria (Rev. July 2012) for a unit operating continuously (8,760 hours per year). The assumed electricity price is $0.09 per kWh, the federal average electricity price. Lifetime energy cost is the sum of the discounted value of annual energy cost over the assumed 5-year operating life of the device. Future electricity prices and a 3% discount rate are from Energy Price Indices and Discount Factors for Life-Cycle Cost Analysis - 2013: Annual Supplement to NIST Handbook 135 and NBS Special Publication 709 (NISTIR 85-3273-28)
b More-efficient products may have been introduced to the market since this table was published.



An efficient product is cost-effective when the discounted savings (from avoided energy costs over the life of the product) exceed the additional upfront cost (if any) compared to a less efficient option. EPA considers upfront costs and lifetime energy savings when setting required efficiency levels so federal purchasers can assume that ENERGY STAR-qualified products are life cycle cost-effective.


For most applications, purchasers will find that energy-efficient products have the lowest life cycle cost. Agencies may claim an exception to these purchasing requirements through a written finding that no ENERGY STAR-qualified product is available to meet functional requirements, or that no ENERGY STAR-qualified product is life cycle cost-effective for the specific application. Additional information on federal requirements is available.


These requirements apply to all forms of procurement, including project specifications; renovation, repair, maintenance, and energy service contracts; lease agreements; acquisitions made using purchase cards; and solicitations for offers. Energy efficiency requirements should be included in both the evaluation criteria of solicitations and the evaluations of solicitation responses.

Federal Acquisition Regulation (FAR) Part 23.206 requires federal agencies to insert the clause at FAR section 52.223-15 into solicitations and contracts that deliver, acquire, furnish, or specify energy-consuming products. FEMP recommends that agencies incorporate efficiency requirements into both the technical specification and evaluation sections of solicitations.

Note that UPS systems are often acquired through IT service providers. Make sure that such IT service contracts contain appropriate pass-through provisions to require the purchase of ENERGY STAR-qualified products.


When selecting a UPS for your downstream equipment, consider equipment type, size, and number; the level of power conditioning required; redundancy; and the length of uptime required in the event of an outage. In applications where future growth is expected, such as data centers, consider using modular UPS systems that can expand in proportion with the load.

Voltage and frequency dependent (VFD), voltage independent (VI), and voltage frequency independent (VFI) UPS systems offer different levels of power conditioning. VFD models provide the most basic level of protection, while VFI models offer the highest level of protection for downstream equipment; the protection function of VI models fall between that of VFD and VFI. Higher levels of power conditioning generally result in lower UPS system efficiency, so choose the lowest level of protection needed for your application.

For battery-based UPS systems, use a design approach that keeps the load factor as high as possible, and account for any peak-load and partial-load operating conditions. The efficiency of UPS systems varies with loading; typically the more highly loaded they are, the more efficient. Lightly loaded systems could be losing 15% or more of the energy supplied to the equipment downstream. The loss is from the power conversion within the UPS, which creates heat that must then be managed. For systems that are constantly operated below design conditions, consider a modular UPS system to accommodate partial-load conditions and future growth.

Accurate equipment load estimates can prevent gross over-sizing and the resultant under-loading of UPS systems. Selecting efficient UPS models, coupled with right-sizing the system, can result in direct 24-hour-a-day energy savings by reducing both UPS and cooling power consumption. When purchasing new UPS systems, look for models that are efficient through most of the design range and that allow power data collection to track power usage.

UPS systems are often used in data centers. Agencies should consult the Center of Expertise for Energy Efficiency in Data Centers website for information on energy-efficient design strategies and opportunities. DOE has partnered with key public and private stakeholders to provide technical information, tools, best practices, and analysis that assist government agencies with reducing energy use in data centers. Purchasing efficient products for use in data centers can be an important component to meeting data center energy reduction goals.


When using multi-normal-mode UPS systems, consider switching to lower energy-consuming modes during operations for which the highest level of protection is not required. Check the UPS periodically to ensure battery and capacitor parts are maintained per manufacturers' instructions.

Lawrence Berkeley National Laboratory provided supporting analysis for this acquisition guidance.

Updated January 2015