from Kevin in Sheboygan, WI:
#497
if you leave a room and turn a light off and come back a few minutes later and turn the light back on does it take more energy to turn the light back on, or should you just leave the light on
This depends on the amount of time that the bulb is on.
Even when turned on and off frequently, a CFL uses less energy than its incandescent equivalent. While there is a brief surge in energy use when a CFL is turned on, with today's starting technology, that surge usually lasts about a tenth of a second and consumes about as much energy as five seconds of normal operation.
However, turning a CFL on and off frequently can shorten its life. To take full advantage of the energy savings and long life of ENERGY STAR qualified CFLs , it is best to use them in light fixtures you use the most and are on for at least 15 minutes at a time. Good locations include outdoor light fixtures, indoor fixtures in the living room, family room, kitchen, bedroom, recreation room, etc. This is not to say you should leave your lights on all day if you use ENERGY STAR qualified CFLs . It is still a good habit to turn the lights off when you leave the room for an extended period of time.
Published Monday, September 28, 2009