Introduction Switching off fluorescent lamps whenever a room is unoccupied saves energy. Energy codes mandate automatic shutoff of non-residential buildings. Occupancy sensors mandated switching off lighting when leaving a room@ and automated building systems save energy by removing lighting load when not being used. Frequent switching of lamps@ however@ may shorten their operating life. It is the intent of this paper to give some guidance in the selection of ballast type as a function of lamp switching rate to achieve the desired energy savings while maintaining acceptable lamp life.