Notes that most studies on the effectiveness of energy conservation measures focus on past energy consumption and savings achieved after implementation. Presents a case where the effectiveness of an energy management system (EMS) was observed both before installation and after the system was removed after 4.5 years' operation in a small office building. Presents a comparison of the whole facility energy use for the four year period (1993-97) after the removal of the EMS with the EMS operation period. Finds that the energy consumption and peak electrical demand increased significantly after the removal of the EMS.