Is it more costly to turn lights on & off (say in a 5min. period) than to just leave them on?

Question

I was told it takes more power to turn the lights on. Is this true?

Answer 1

For incandescent lights it saves energy to turn off the lights even for a few seconds (but not much in that case).

For fluorescent lights, you should turn them off anytime you will be out of the room for more than a minute. Of course with CLFs you also have a "cost" in turning them off in that every on/off cycle reduces its longevity. If you were going in and out of the room every couple of minutes all day, it would make more sense to leave them on constantly.

Answer 2

well they say it wont matter..i read in a magazine

Answer 3

The short answer is that it is more conservative to turn them off and then back on instead of leaving them on.

The long answer is that when you turn them on, there will be an initial power surge while they reach a steady state.

However, this surge will only last milliseconds or even microseconds. That means virtually no excess power is wasted.

The only benefit of leaving them on is if you are going to be leaving the room for less than one-thousandth of a second. In that case the power surge will use more energy than leaving them on for an extra millisecond.

Answer 4

NO. It is not a car.