When a fluorescent light is first switched on, there is a higher current draw for a second or so. However, the length of time for this higher current draw is so short that it has almost no effect on energy use. Leaving a fluorescent light on for more than a few minutes will use more energy than turning it off and turning it back on when needed.
A ballast regulates current to the lamp during startup and operation. Turning lights on and off frequently will have some impact on lamp and ballast life. However, the old principle of leaving lights on if the room is unoccupied for less than 15 minutes, no longer holds true. (Source: www.energy.gov & Duke Energy)
Lighting manufacturers now recommend that fluorescent lamps be turned off if the room will be unoccupied for more than two or three minutes. This is the result of technology advances in electronic ballasts, which can handle frequent on-off cycling with little loss of lamp and ballast life. This also applies to LED lighting, which Meredith has recently begun to implement in parts of the campus. If you have an individual workspace, please turn off your lights when leaving your space for more than a few minutes.
—Submitted by Dave Lyons, Energy Manager