I read in a science question/answer book that it is takes as much energy to turn on a fluorescent light as it doesn to run it for 1 hour. So if this is true, it would mean that if you plan on using the light again within an hour, it is more efficient to leave it on, rather than turning it off and then back on again. Fluorescent lights are aleady much more efficient than incandecent light bulbs, but why not take the time to save an extra 10 of a cent. So has anyone else heard this before, or seen it somewhere else? I have only seen it in that one source, so I dont know if it is true, or if it is by how much.