In 1993, the U.S. Environmental Protection Agency initiated a project to design, build and demonstrate a high efficiency commercial rooftop air conditioning unit. The unit was designed by Hibberd Consulting of Westminster, Colorado, and was built by LaSalle Manufacturing Corporation of Houston, Texas. The rooftop unit was then tested at Texas A&M University. The economics of manufacturing, purchasing and operating were also evaluated. This report summarizes the testing of the unit and an evaluation of the economics of the system.