Dear Mr. Energy,
My dad and I are in a disagreement. He says that it uses more money and energy to turn on the fluorescent lights in our car repair shop than it does to simply let them run all night, and I think he’s nuts. Who’s right?
–Suffering Son in Sanford
The truth is that you and your dad are both right. Kind of. Fluorescent lights actually do draw more energy when they’re first turned on than it takes to keep them on, but this only really matters if you’re going to have the light on a very short time. After a couple of minutes the difference is moot. In the case of a place of business that doesn’t need its lights on all night, it is significantly more energy efficient to turn the lights off than to leave them on. This applies to both the long, traditional fluorescent lights like the kind you probably have in your shop as well as to compact fluorescent lightbulbs, which are just a different form of the same technology.