Forced air unit heaters (left) in the South Dakota Air and Space Museum are being replaced with infrared heaters (right) during a renovation project by Montana-Dakota Utilities, Co., in Box Elder, S.D., Feb. 26, 2013. The 28th Civil Engineer Squadron worked alongside regional partners to complete the project, expected to save the SDASM approximately $6,500 per month. (U.S. Air Force photo illustration by Airman Ashley J. Thum/Released)