Rooftop Air Conditioner Update: Technology Procurement Winners Available for Purchase

August 1, 2002

A year ago, the FEMP Focus featured an article on improving the energy efficiency of packaged rooftop systems. (See "Improving Energy Efficiency in Packaged Rooftop Systems," FEMP Focus, July 2001.) The article described the needs and opportunities for higher efficiency and progress along several fronts, including mandatory minimum standards, the Consortium for Energy Efficiency's (CEE's) High Efficiency Commercial Air Conditioning initiative, and new ENERGY STAR® ratings for these products. The article also reported on a plan by the Defense Logistics Agency (DLA) and DOE's Pacific Northwest National Laboratory (PNNL) to issue a coordinated innovative procurement for a "new generation" of packaged rooftop systems in small commercial sizes (between 65,000 and 135,000 Btu per hour). Some of the winning units are now available for purchase by Federal government and private entities.

The procurement, supported by both FEMP and DOE's Office of Building Research and Standards, in addition to the Department of Defense, seeks to promote the manufacture of equipment that improves both performance and cost-effectiveness compared to models now on the market. PNNL provided the technical and market research to initiate the procurement, and also recruited several large prospective buyers, both within and outside the Federal government.

The solicitation, issued in early January 2002, required that equipment meet at least the CEE Tier II / ENERGY STAR®/ FEMP efficiency levels, at a minimum, and prescribed a cost-effectiveness rating formula that balanced the initial price of the equipment against expected energy costs, taking into account average weather conditions and both full- and part-load efficiencies. Winning models with the lowest total life-cycle cost have been selected, and PNNL has negotiated basic ordering agreements reflecting the offered prices and terms with two manufacturers for the following products:

Lennox Industries
Model Btu/Hour Energy Efficiency Ratio Integrated Part-Load Value Price

Global Energy Group
(Available this Fall)
Model Btu/Hour Energy Efficiency Ratio Integrated Part-Load Value Price

Federal buyers will soon be able to purchase these products through DLA's catalogs or by visiting the Unitary Air Conditioner Technology Procurement web site. In the meantime, purchasers can contact Brad Hollomon of PNNL at 202-646-5043 or hollomon@ The program's web site also contains useful advice on typical air conditioner design features, as well as a life-cycle cost comparison tool that grew out of the selection criteria for the procurement. It is designed to help users select optimal equipment by comparing different models' life-cycle cost at their respective efficiency levels. Among the screening tool's key features, the menu-driven software:

  • quickly estimates life-cycle cost, simple payback, rate of return, and savings-to-investment ratio;
  • accommodates equipment with one or two compressor stages;
  • accounts for part-load, as well as full-load efficiencies;
  • simulates operation under specific climate conditions at any of 237 U.S. locations;
  • reflects user-specified air conditioning requirements and building use patterns;
  • allows a comparison of alternative equipment choices with user-specified electric rate and financial assumptions; and
  • provides results as downloadable graphic files for further analysis and presentation.

This is a line graph that depicts discounted costs for two air conditioners: a standard one and one that costs more but is more efficient.  The horizonal axis represents the life of the system in 5 year increments starting with 0 years and ending with 15 years.  The vertical axis shows the cumulative discounted cost in dollars. The costs are represented in 500 dollar increments starting with 0 dollars and ending with 9500 dollars.  For the standard air conditioner, 0 year costs are 4000 dollars, 5 year costs are 6500 dollars, 10 year costs are 8300 dollars, and 15 year costs are 9500 dollars.  For the higher cost but more efficient air conditioner, 0 year costs are 4500 dollars, 5 year costs are 6500 dollars, 10 year costs are 7800 dollars and 15 year costs are 8750 dollars.
This sample output graph indicates cumulative costs of acquiring and operating two hypothetical air conditioners, one with a higher price and more efficient than the other

As electricity rates soar around the country, air conditioning is taking a bigger bite out of everyone's utility budgets. New high-efficiency air conditioners may make sense for your Federal facility.

For more information, please contact Alison Thomas of FEMP at 202-586-2099 or