Hanson provided retro-commissioning services for the Koke Mill Medical Center in Springfield, Ill.  The two-story, 98,000-square-foot facility was built in 1998 and includes medical offices, outpatient surgery areas, physical therapy, a pharmacy and an Express Care. The retro-commissioning study identified nine energy conservation measures that resulted in a calculated 24.1 percent decrease in annual utility costs. The payback on individual measures ranged from 0.3 to 7.8 years with a total average payback for all measures of 1.8 years.