Sustainability Myths: Leaving the Lights On – That’s a Turnoff

We have all heard this rumor – turning the lights off when you leave the room doesn’t actually save energy. In fact, many people think it wastes energy when you have to start the lights back up. However, this has proven to be untrue, regardless of the type of bulbs you use.

Myth: It takes more energy to turn florescent lights back on than is saved turning them off. While this is a myth, it is easy to see where the misconception began. Rumor has it that it takes an increased amount of energy to start the lights back up than is needed for normal light use. This is true, but how much more energy is where the myth comes in. While many people assume that turning the fluorescents on is an enormous energy surge, in fact the energy increase only lasts for approximately 1/120th of a second, and only amounts to the total energy used for a few seconds of normal light use. This means that turning the lights off for any more than 5 seconds saves more energy than it takes to turn the lights back on.

The same applies to incandescent bulbs, which are in fact so energy inefficient that turning them off for any period of time is more efficient than leaving them on. Only 10-15% of the total energy incandescent bulbs require is actually used to produce light – the rest only produces heat.



By Grace Interlichia, class of 2013


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