In commercial, industrial or institutional buildings, a Bio-Shield UV-C installation offers the most rapid payback in the industry. A typical installation can pay for in less than two years and save thousands of dollars thereafter in energy and maintenance costs. This is possible because the devices continually clean coils, drain pans, plenums and ducts, reducing or eliminating costly cleaning programs. HVAC energy costs are lowered by improving heat transfer and increasing net cooling capacity. General IAQ is improved for better productivity and less absenteeism. Product quality, shelf life and yield in processing plants are improved as well.