does it cost more to turn a light off and on than to keep it on?

Answer 1

Nope. they did this test on Mythbusters a few weeks ago. it is an urban myth.

xxR

Answer 2

What a load of wrong answers. It should be obvious even to an idiot that it costs energy/money to have a light of ANY type ON. And it will cost nothing/zero, to have it off. This applies to all and every light ever made. The fluorescent tube story is also a myth. Old tubes of 30+ years ago did have a shorter life if switched frequently, but modern tubes have no such problem due to electronic control gear and shielded cathodes. The running cost of a lamp will always be more than the early replacement cost caused by overswitching. A fluorescent lamp will have a typical life of 18000 hours.

SO!! switch OFF if not required,save money and lamp life.

Answer 3

ACtually I think it's a function of the type of light. For instance, if you run an industrial facility, with the big sodium lights, it is cheaper to leave them on the whole time the factory is running than to turn them off when it gets sunny and turn them back on when clouds come along. Of course, it probably is cheaper to turn the lights off at night when no one is there, because the expense of keeping them on ALL the time would be higher than the initial jolt of getting the lights warmed up and shining in the morning when people come back in. Same thing with street illumination.

But I agree with the first responder. Chances are there is no big change when talking about regular incandescent or compact fluorescent (household) lights. It's the turning on and off of major appliances that have big capacitors, motors, induction coils, etc, tht really draws the juice. Just keep an eye on your den lamp when you turn on your TV. I bet it dims for about a second while the screen flickers on. That's because all the inner guts of the TV need to charge up before they reach running condition.

Answer 4

It costs more to keep it on because you waste energy to keep it on then you have to pay for more energy to keep it on. You could also test this.
Get 2 families to agree to have 1 live with all their lights on for a couple days and the other to keep their lights off for the same amount of days.

Answer 5

absolutely not. The energy required to start a bulb up is insignificant compared to the amount it uses when running. This is even true of the energy saving light bulbs. The only ones I'm not sure about are the long tubes used in offices. They require a 'striking current' which is pretty large

Answer 6

Change your ordinary light bulbs for energy saving ones. Priced from just £5, energy efficient light bulbs last 12 times longer and for each bulb you fit, you can save up to £9 on your annual electricity bill.Turn lights off when not needed and that will save on bulbs AND electricity.

Answer 7

It costs nothing to keep it off until needed.

Answer 8

Does it cost more calories to switch that brain off than turning it off and on ? Obviously you must be saving calories. Ever heard of electricity? Electric meters? What is more disturbing is everyone giving you serious answers to such a stupid question.

Answer 9

no but everytime you switch it on it puts a surge into the bulb which will shorten it's life fractionally.
The relevant cost of this is negligable - it would cost more to leave the light on than to replace the bulb.

Answer 10

It costs more to turn the light off and on. Leave the light on
and save money.

Answer 11

That depends on how long you are going to be out of the room. If you are only out for a minute or two it is better to leave it on. It takes more energy for the filament to heat up than it does if left on.