Federal purchases of light commercial heating and cooling equipment must be ENERGY STAR-qualified. Federal laws and requirements mandate that agencies meet these efficiency requirements in all procurement and acquisition actions that are not specifically exempted by law. This product overview explains how to meet energy-efficiency requirements for Federal purchases of light commercial heating and cooling equipment and how to maximize energy savings throughout products' useful lives.
This acquisition guidance applies to commercial central air conditioners (CACs) and air-source heat pumps (ASHPs) that operate on three-phase electric current and have cooling capacities of 240,000 British thermal units per hour (Btu/hr) or less. Packaged terminal air conditioners and heat pumps are excluded.
Meeting Efficiency Requirements for Federal Purchaces
Visit the ENERGY STAR website for the most up-to-date light commercial heating and cooling equipment efficiency levels and product specification information.
Reducing Energy Costs: Save Up to $1,785 In Energy Costs When You Buy ENERGY STAR–Qualified Products
FEMP has calculated1 that a commercial CAC unit meeting ENERGY STAR requirements saves money if priced no more than $735 above the less efficient alternative. The best available product saves the average user even more: $1,785. The complete cost-effectiveness for a 10-ton commercial CAC operated at 1,500 full-load hours per year is provided in table 1.
|Table 1. Lifetime Savings for Efficient Commercial CACs|
|Performance||ENERGY STAR Best Availablea||ENERGY STAR Required||Less Efficient|
|Energy Efficiency Ratio (EER)b||12.5||11.7||11.2|
|Annual Energy Use||14,440 kWh/year||15,385 kWh/year||16,070 kWh/year|
|Annual Energy Cost||$1,295||$1,385||$1,445|
|Lifetime Energy Costb||$15,385||$16,435||$17,170|
|Lifetime Energy Cost Savings||$1,785||$735||======|
a More-efficient products may have been introduced to the market since this table was published.
ENERGY STAR Is 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 upfront cost (if any) compared to a less efficient option. ENERGY STAR considers upfront costs and lifetime energy savings when setting required efficiency levels. 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.
Complying with Contracting Requirements
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 offer. 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.
Buyer Tips: Choosing Efficient Light Commercial Heating and Cooling Equipment
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:
- 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.
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: Using 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 hydrochlorofluorocarbons (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 product overview.
Updated February 2013
1 Based on the following assumptions: Annual Energy Use is based on the standard DOE test procedure for a 10-ton split system commercial CAC operated 1,500 equivalent full-load hours per year. The performance of the less efficient model is assumed to just meet Federal Appliance Standards, while that of the required model meets the current ENERGY STAR qualification criteria. The most efficient model is from the ENERGY STAR List of Qualified Products (posted March 2013). The assumed rate of electricity is $0.09 per kWh, the average at U.S. Federal facilities. Lifetime energy cost is the sum of the discounted valued of annual energy cost with an assumed commercial CAC life of 15 years. Future electricity prices and a 3% discount rate are from "Energy Price Indices and Discount Factors for Life Cycle Cost Analysis - 2012: Annual Supplement to NIST Handbook 135 and NBS Special Publication 709." (NISTIR 85-3273-27).