does turning on and off a light switch make the bulb burn out?

Question

Or does it save energy and make the light bulb last longer?

Answer 1

turning on a bulb will decrease its life when you turn on the bulb, the current surges thru the filament, this surge is most responsible for a bulb "blowing" Switching to Cf bulbs removes the filament from the equation and uses less electricity to run the bulb

Answer 2

The best way to make a light bulb last longer is to run it on reduced voltage. I can't remember the equation offhand but for each volt you reduce the voltage below rated voltage the bulbs life will be increased by a certain exponential amount.

You can actually buy 130V rated bulbs and run them on a 120V system and have much greater bulb life. At my house we have a couple instances where we run incandescent bulbs. The voltage here is usually around 125V and these bulbs are 130V rated. They have been running for a pretty good long time. Certainly for much much longer than cheap 120V bulbs did. Running at reduced voltage does save a slight amount of energy as well.

Switching on and off does cause bulbs to burn out sooner as well. The filament in the bulb is not really a fixed resistance. When cold the resistance is a good bit lower than when its on and hot. The shock from the starting inrush can cause filaments to fail. You can actually measure this in a few ways. One way is to directly measure the resistance of a cold bulb. Using ohms law you can find the inrush current. Then you can measure the current when the bulb is running and use ohms law to find the resistance when the bulb is hot.

As an aside, sometimes if you don't turn a dimmer up fast enough you'll reach a point where the filament is not hot enough to really raise the resistance and the voltage is high enough that a fair amount of current will flow. This can trip breakers, fry dimmers or blow bulbs. I've only seen this happen once though. All those bulbs have been changed to fluorescent and the dimmers eliminated.

Answer 3

The stress of the electricity coming into a cold filament can cause the bulb to burn out. Bulbs that are on constantly will last longer. The oldest continuously-burning lightbulb has been going for 106 years, but it's never turned off. It has been turned off a few times, not at all since 1976. Read about it at the link below.

You do save electrical energy by turning off the light, but it decreases its lifespan. Bulbs are so cheap nowadays that it's cheaper to replace the bulb than to leave it burning, usually.

I'm not sure how bulbs without filaments are affected by being turned on and off, but I've had some compact fluorescents go out on me an awful lot sooner than the 7-10 years they claim they'll last.

Answer 4

When The Lights Burn Out

Answer 5

According to Mythbusters, turning the lights off - even if you turn them on and off constantly - won't negatively impact the lifetime of the bulb, AND will save energy. So even if you're just leaving for a few minutes, turn out that light!

Answer 6

if you turn off a light bulb and wait more than half a second then its worth to turn off the bulb. I saw this experiment done on Mythbusters. They wanted to know what was the time it took for the energy that it'd take to turn on the lightbulb to cancel out the benefit of turning off the lightbulb. Turns out its half a second o.o

Answer 7

While it may slightly shorten the life of an incandescent lamp it is worth the energy savings.

If you are talking about a compact fluorescent (CFL) or any type of fluorescent lamp it will severely shorten the life of the lamp. This is why CFLs burn out in bathrooms a lot. They get cycled on and off much more than a kitchen application.

Answer 8

The answer is yes the more times you cycle a lightbulb the sooner it will fail especially fluroescent lamps I am A cettified lighting expert with a degree from the GE lighting institute and I can assure you the more you cycle the lamp the sooner it will stop working...and of course the more you leave it off the more energy you will save

Answer 9

The filament heating & cooling shortens the bulb's life.
But turning it off obviously save energy; it's a trade-off.

Answer 10

no, the filament interior the bulb stops the bypass of electricty and reasons amperage which heats up and reasons gentle. without the filament (burned out) the electricty does not bypass in the process the bulb and hence isn't used and you're no longer charged.