The Federal Energy Management Program (FEMP) provides acquisition guidance for commercial central air conditioners (CACs). This equipment falls under the light commercial heating and cooling equipment product category covered by ENERGY STAR efficiency requirements. Federal laws and requirements mandate that agencies purchase ENERGY STAR-qualified products 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 associated ENERGY STAR efficiency requirements apply to CACs with cooling capacities of 240,000 British thermal units per hour (Btu/hr) or less.
This acquisition guidance was updated in June 2016.
Find Product Efficiency Requirements
The U.S. Environmental Protection Agency (EPA) provides light commercial heating and cooling equipment efficiency levels and product specification information on its ENERGY STAR website. Manufacturers meeting these requirements are allowed to display the ENERGY STAR label on complying models. Federal buyers can use ENERGY STAR's list of certified light commercial heating and cooling equipment to identify or verify complying models.
Make a Cost-Effective Purchase: Save $807 or More by Buying ENERGY STAR
FEMP has calculated that the required ENERGY STAR-qualified CAC models save money if priced no more than $807 above the less efficient model. The best available CAC model saves up to $2,740. Table 1 compares three types of CAC purchases and calculates the lifetime cost savings of purchasing efficient models. Federal purchasers can assume products that meet ENERGY STAR efficiency requirements are life cycle cost-effective.
|Table 1. Lifetime Savings for Efficient Central Air Conditioner Models|
|Performance||Best Available||ENERGY STAR||Less Efficient|
|Annual Energy Use||13,740 kWh||15,385 kWh||16,071 kWh|
|Annual Energy Cost||$1,277||$1,430||$1,494|
|Lifetime Energy Cost||$16,154||$18,087||$18,894|
|Lifetime Cost Savings||$2,740||$807||======|
Energy Efficiency Ratio (EER): The ratio of the cooling capacity to the power input.
Annual Energy Use: Based on the test method referenced in 10 CFR 430, Subpart B, Appendix M.
Annual Energy Cost: Calculated based on an assumed electricity price of $0.09/kWh, which is the average electricity price at federal facilities.
Lifetime Energy Cost: Future natural gas price trends and a 3% discount rate are from Energy Price Indices and Discount Factors for Life-Cycle Cost Analysis - 2015: Annual Supplement to NIST Handbook 135 and NBS Special Publication 709 (NISTIR 85-3273-30).
Lifetime Cost Savings: The difference between the lifetime energy cost of the less efficient model and the lifetime energy cost of the ENERGY STAR model or best available model.
Best Available Model Column
Calculated based on the April 2016 ENERGY STAR-Qualified Products List. More efficient models may be introduced to the market after FEMP's acquisition guidance is posted.
ENERGY STAR Model Column
Calculated based on April 2016 ENERGY STAR efficiency levels. Federal agencies must purchase products that meet or exceed ENERGY STAR efficiency levels.
Less Efficient Model Column
Calculated based on typical products used in non-federal applications.
Determine When ENERGY STAR 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. ENERGY STAR considers up-front costs and lifetime energy savings when setting required efficiency levels. Federal purchasers can assume 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 federal efficiency requirements (e.g., the best available model).
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 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.
Light Commercial Heating and Cooling Equipment Schedules and Product Codes
Buyer Tips: Make Informed Product Purchases
The ENERGY STAR performance requirements save energy nationwide, but climate does substantially impact the performance of light commercial heating and cooling equipment. You can achieve additional, sometimes quite significant, savings by optimizing your heating and cooling equipment for the specific climate conditions at your site. Consider if the following technologies meet your site's specific needs:
- Air-source heat pumps (ASHPs) for hot/dry and mixed or moderate climates
- Economizers in dry climates
- Two-speed fans and modulating compressors for areas with high temperature variations.
CACs that are designed to provide more sensible cooling perform better in dry climates, whereas those designed for greater moisture removal perform better in humid climates. In hot climates, consider installing CACs that exceed minimum performance requirements. Depending on utility rates, additional energy and cost savings can be achieved.
Many states and electric utilities offer rebates or other incentives for the purchase of ENERGY STAR-qualified products. Use the ENERGY STAR Rebate Finder to see if your local utility offers these incentives. FEMP’s Energy Incentive Program helps federal agencies take advantage of these incentives by providing information about the funding-program opportunities available in each state.
Air-Source Heat Pumps
Local climate conditions particularly affect ASHPs because the units use outdoor air as both a heat source and heat sink. An advantage of ASHPs is that one system can provide both space heating and cooling in a building. Heat pumps work well in hot/dry and mixed (or moderate) climates. Cold climates require specially designed heat pumps that can operate at lower ambient temperatures before switching to resistance heating.
In dry climates, economizers can substantially reduce energy use by using outside air to cool interior spaces. When the ambient temperature and humidity conditions are favorable, economizers open dampers to allow more outside air in and reduce the amount of indoor air recirculated. Under certain conditions, the economizer can shut down the condenser unit and cool a building using outdoor air only.
Other technologies that reduce energy use and operating cost include two-speed fans, which allow for decreased energy use in ventilation-only mode when neither heating nor cooling is needed, and modulating compressors, which use less energy than single-speed models at partial loads. Two-speed fans should be used with modulating compressors to match the airflow with the amount of cooling provided.
Economizers, two-speed fans, and other features usually require operation by an appropriate and well-calibrated control system. The American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) provides guidance on proper control settings through its published Standard 90.1-2007. Automated fault detection and diagnostics control systems can alert building operators to any equipment failures, such as low refrigerant charge, that require maintenance or repair.
Federal buyers should require that commercial CACs and ASHPs be installed in accordance with the HVAC Quality Installation (QI) Specification published by the Air Conditioning Contractors of America. Installation problems—such as oversizing, improper charging, and leaky ducts—result in efficiency losses, occupant discomfort, and shortened equipment life. Requiring the contractor to follow the HVAC QI Specification will address these and other problems during installation and ensure that the installed system saves energy and money.
User Tips: Use Products More Efficiently
Proper maintenance of commercial CACs and ASHPs is essential for effective and efficient operation. The Consortium for Energy Efficiency publishes the Guidelines for Energy-Efficient Commercial Unitary HVAC Systems that provides tips on properly operating and maintaining commercial ASHPs.
Refrigerants with ozone-destroying hydro chlorofluorocarbons (HCFCs) were commonly used in commercial CACs and ASHPs until recently. When retiring light commercial heating and cooling equipment that contains HCFCs, the Clean Air Act requires that a certified technician recover the refrigerant on site and dispose of it in an environmentally friendly manner. It is a violation of federal law to dispose of HCFCs improperly.
Lawrence Berkeley National Laboratory provided supporting analysis for this acquisition guidance.