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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.

This acquisition guidance was updated in July 2018.

Find Product Efficiency Requirements

Federal purchases must meet or exceed the minimum efficiency requirements in Table 1.

Table 1. Efficiency Requirements for Air-Cooled Electric Chillers (Energy Efficiency Ratio [EER], Btu/watt)
Chiller TypeCapacityFull-Load Optimized Applications
(products must meet both levels)
Part-Load Optimized Applications
(products must meet both levels)
Full Load EfficiencyIntegrated Part-Load Value (IPLV)Full Load EfficiencyIntegrated Part-Load Value (IPLV)
Air-Cooled, All Compressors< 150 tons10.50013.7009.70015.800
≥ 150 tons10.70014.0009.70016.100


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 10.7 EER level saves money if priced no more than $34,600 above the less efficient model. The best available model saves the average user more: $55,600 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
PerformanceBest AvailableRequired ModelLess Efficient
Full Load Efficiency (EER)11.110.710.1
Annual Energy Use (kWh)378,400392,500415,800
Annual Energy Cost ($/yr)$34,200$35,400$37,600
Lifetime Energy Cost (23 years)$608,200$630,900$668,400
Lifetime Energy Cost Savings$55,600$34,600----
View the Performance and Model Assumptions for Table 2

Performance Column

Full Load Efficiency: The energy efficiency ratio (EER) is determined at a single rated condition and is defined as the ratio of cooling capacity—or heat removed in Btu/h—to the total input rate of electric power applied, in watts. The higher the EER the more efficient the chiller.

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

Annual Energy Cost: Calculated based on an assumed electricity price of $0.09/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 based on federal guidelines (NISTIR 85-3273-32) from the Annual Supplement to NIST Handbook 135 and NBS Special Publication 709, Energy Price Indices and Discount Factors for Life Cycle Cost Analysis – 2017.

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 May 2018. 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.

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 that ENERGY STAR-qualified products and products that meet 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).

Air-Cooled Electric Chillers Cost Calculator

Users who wish to determine a product's cost-effectiveness for their application may do so using the Energy Cost Savings Calculator for Air-Cooled Electric Chillers.

Claim an Exception to Federal Purchasing Requirements

Products meeting ENERGY STAR or 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 FEMP-designated or ENERGY STAR-qualified product is available to meet functional requirements, or that no such product is life cycle cost-effective for the specific application. Learn more about 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 technical specifications, the evaluation criteria of solicitations, and the evaluations of solicitation responses.

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 DOD FedMall (formerly DOD eMALL). Products sold through DLA are codified with a 13-digit National Stock Number (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 and ENERGY STAR.

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 numbers.

Air-Cooled Electric Chiller Schedules and Product Codes

GSA offers chillers through Schedule 73, Category 302 49; Schedule 84, Category 246 422; and Schedule 51 V, Category 639 001.

The DLA ENAC for air-cooled chillers is JS.

The UNSPSCs 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, Purchasing Energy-Efficient 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 integrated part-load value (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.

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