The Federal Energy Management Program (FEMP) provides acquisition guidance for air-cooled electric chillers, a product category covered by FEMP efficiency requirements. Federal laws and requirements mandate that agencies purchase ENERGY STAR-qualified or FEMP-designated products in all product categories covered by these programs and in any acquisition actions that are not specifically exempted by law.

FEMP’s acquisition guidance and efficiency requirements apply to air-cooled chillers that provide space cooling in federal buildings. Product performance must be measured in accordance with AHRI 550/590 test procedures. Free-cooling and combination chiller-heat pump units are excluded. Water-cooled electric chillers are covered by FEMP efficiency requirements under a separate product category.

This acquisition guidance was updated in September 2022.

Find Product Efficiency Requirements

Federal purchases must meet or exceed the minimum efficiency requirements in Table 1. Note that efficiency requirements differ by full- and part-load optimized applications.

Table 1. Efficiency Requirements for Air-Cooled Electric Chillers (Energy Efficiency Ratio [EER], Btu/watt)
Chiller Type Capacity Full-Load Optimized Applications
(products must meet both levels)
Part-Load Optimized Applications
(products must meet both levels)
Full Load Efficiency Integrated Part-Load Value (IPLV) Full Load Efficiency Integrated Part-Load Value (IPLV)
Air-Cooled, All Compressors < 150 tons 10.890 13.700 9.700 16.860
≥ 150 tons 10.964 14.000 9.700 17.130


Make a Cost-Effective Purchase: Reduce Operating Costs by Buying a FEMP-Designated Product

FEMP has calculated that a 175-ton air-cooled chiller meeting the required 10.96 EER efficiency level saves money if priced no more than $32,983 above the less-efficient model. The best available model saves the average user more: it is cost-effective up to a price premium of $127,331 above the less efficient model. Table 2 compares three types of product purchases and calculates the lifetime cost savings of purchasing efficient models. Federal purchasers can assume products that meet FEMP-designated efficiency requirements are life cycle cost-effective.

Table 2. Lifetime Savings for an Efficient 175-ton Air-Cooled Chiller in a Full-Load Application
Performance Best Available Required Model Less Efficient
Full Load Efficiency (EER) 13.44 10.96 10.30
Annual Energy Use (kWh) 312,430 383,072 407,767
Annual Energy Cost ($/yr) $26,978 $33,078 $35,211
Lifetime Energy Cost (23 years) $417,280 $511,629 $544,611
Lifetime Energy Cost Savings $127,331 $32,983 ----

Note: Monetary and energy use values in this table are rounded to the nearest hundred. 

View the Performance and Model Assumptions for Table 2

Performance Column

Annual Energy Use: Assumed 2,000 operating hours per year, for 23 years.

Annual Energy Cost: Calculated based on an assumed electricity price of 8.6¢/kWh, which is the average electricity price at federal facilities in the United States.

Lifetime Energy Cost: Future electricity price trends and a 3% discount rate are from the Annual Supplement to NIST Handbook 135 and NBS Special Publication 709, Energy Price Indices and Discount Factors for Life Cycle Cost Analysis – 2022 (NISTIR 85-3273-37 update 1).

Lifetime Energy Cost Savings: The difference between the lifetime energy cost of the less efficient model and the lifetime energy cost of the required model or best available model.

Best Available Model Column

Calculated based on the highest efficiency model identified in publicly provided manufacturer data as of June 2022. Note that more efficient models may be introduced to the market after FEMP's acquisition guidance is posted.

Required Model Column

Calculated based on FEMP-designated efficiency requirements. Federal agencies must purchase products that meet or exceed FEMP-designated efficiency levels.

Less Efficient Model Column

Calculated based on median efficiency of models identified in publicly provided manufacturer data as of June 2022.

Determine When FEMP-Designated Products Are Cost-Effective

An efficient product is cost-effective when the lifetime energy savings (from avoided energy costs over the life of the product, discounted to present value) exceed the additional up-front cost (if any) compared to a less efficient option. FEMP considers up-front costs and lifetime energy savings when setting required efficiency levels. Federal purchasers can assume products meeting FEMP-designated efficiency requirements are life cycle cost-effective. In high-use applications or when energy rates are above the federal average, purchasers may save more if they specify products that exceed FEMP’s efficiency requirements (e.g., the best available model).

Claim an Exception to Federal Purchasing Requirements

Products meeting FEMP-designated efficiency requirements may not be life cycle cost-effective in certain low-use applications or in locations with very low rates for electricity or natural gas. However, for most applications, purchasers will find that energy-efficient products have the lowest life cycle cost.

Agencies may claim an exception to federal purchasing requirements through a written finding that no ENERGY STAR-qualified or FEMP-designated product is available to meet functional requirements, or that no such product is life cycle cost-effective for the specific application. Get additional information on federal product purchasing requirements.

Incorporate Federal Acquisition Regulation Language in Contracts

These mandatory requirements apply to all forms of procurement, including construction guide and project specifications; renovation, repair, energy service, and operation and maintenance (O&M) contracts; lease agreements; acquisitions made using purchase cards; and solicitations for offers. Federal Acquisition Regulation (FAR) Part 23.206 requires agencies to insert the clause at FAR section 52.223-15 into contracts and solicitations that deliver, acquire, furnish, or specify energy-consuming products for use in federal government facilities. To comply with FAR requirements, FEMP recommends that agencies incorporate efficiency requirements into both the technical specification and evaluation sections of solicitations.

Find Federal Supply Sources

The federal supply sources for energy-efficient products are the General Services Administration (GSA) and the Defense Logistics Agency (DLA). GSA sells products through its Multiple Awards Schedules program and online shopping network, GSA Advantage!. DLA offers products through the Defense Supply Center Philadelphia and online through FedMall (formerly the U.S. Department of Defense eMALL). Products sold through DLA are codified with 13-digit National Stock Numbers (NSN) and, in some cases, a two-letter Environmental Attribute Code (ENAC). The ENAC identifies items that have positive environmental characteristics and meet standards set by an approved third party, such as FEMP.

The United Nations Standard Products and Services Code (UNSPSC) is a worldwide classification system for e‑commerce. It contains more than 50,000 commodities, including many used in the federal sector, each with a unique eight-digit, four-level identification code. Manufacturers and vendors are beginning to adopt the UNSPSC classification convention, and electronic procurement systems are beginning to include UNSPSC tracking in their software packages. UNSPSCs can help the federal acquisition community identify product categories covered by sustainable acquisition requirements, track purchases of products within those categories, and report on progress toward meeting sustainable acquisition goals. FEMP has developed a table of ENERGY STAR and FEMP-designated covered product categories and related UNSPSC codes.

Air-Cooled Electric Chiller Schedules and Product Codes

GSA offers chillers through Multiple Awards Schedules Industrial Products 333415REM and Industrial Products 335220D.

DLA offers air-cooled chiller models with the ENAC "JS" at the end of the NSN.

The UNSPSC codes for air-cooled chillers are 40101710 and 40101712.

Buyer Tips: Make Informed Product Purchases

When deciding on a chilled water system, designers must choose between air- and water-cooled chillers. Air-cooled systems eliminate the need for a cooling tower, reducing installation and maintenance costs. However, air-cooled chillers are substantially less efficient than water-cooled models (see FEMP's Covered Product Category: Water-Cooled Electric Chillers). To compare air- and water-cooled options, a detailed life cycle cost analysis can be performed using Building Life Cycle Cost (BLCC) software available through FEMP.

Buyers are advised to purchase the highest-efficiency chiller estimated to be cost-effective. A chiller optimized for high full-load efficiency is appropriate for full-load operating conditions; for a chiller that will be operated at part load, a chiller optimized for high-IPLV efficiency is appropriate.

Refrigerants for chillers fall under EPA's Significant New Alternatives Policy (SNAP) program, which encourages private sector investment in low-emissions technology by identifying and approving climate-friendly chemicals while prohibiting certain uses of the most harmful chemical alternatives.

Many new energy-consuming air-cooled chillers come equipped with Internet of Things (IoT) sensing components and network connectivity. Making a new purchase or replacement represents a prime opportunity to evaluate the vulnerabilities of your network. All IoT-enabled devices introduce novel exposures to potential data breaches. Building controls and heating, ventilating, and air conditioning systems are no exception. Security can almost never be networked in after the fact, and so it is important to ensure that your networked devices are secure. Also, regularly testing for network vulnerabilities is key. For more information on how to build cybersecure networks of building technologies, consult existing FEMP guidance and case studies.

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