...turning off florescent lights?  Or is just keeping them on all of the time better.

The reason why I ask is that some folks I know seem to think that just {u]turning on[/u] florescent lights takes more energy than keeping them on.  Especially if you are in and out of a room a lot, turning them on and off frequently.

Urban legend?

Lights off, no energy use.  Lights on, energy use.  The amount of power to fire up a flourescent light is miniscule.  When you leave the room, turn em off.  Unless you don't care that much about saving energy, then let em burn all day.

BTW, we just switched most of our lights to the compact flourescents.  They are great, seem even brighter than the incadescents they replaced and the wattage is miniscule in comparison.  

^^

Agree with above post on energy use. Not sure about LIFE of bulb though. Constant turning off/on may reduce the life of bulbs?

Flourescent lamps are rated in number of starts, NOT in hours of use. Turning them off will result in less energy use, at the expense of bulb life.  Fourescenta are designed to be turned on and LEFT on.  

Yup, lambda current.  The filament takes slightly more stress heating at an exponential rate from 0 - 120 volts (isn't 120 standard in US households?) when turning the light on.  This can cause miniscule shape change due to thermodynamic factors involved with heat transmission to an object.  Repeated on/off can cause multiple tiny stress fractures to the filament - this is why you hardly ever see a light blow out on you when it's on, but rather when you're [i]turning it on[/i].

Energy use is independent of turning on/off.  The instantaneous nanosecond used to turn on a light uses less energy because it is using a range of energy between 0-60/80/100 watts during that time period, while when it is on, it is a constant energy use that is always non-zero.  If you really want to save energy, kick up your AC 2-degrees, and make sure your freon level is full.

[brown]Evil Jewbroni~[/brown]

Oh Yeah, in the US we be running 120v 60hz. Europeans run 240v 50hz for the most part. WHY STANDARDIZE?

"Filament" holds true for incandescent lights.  Fluorescent lights have no filament.  Remember, he asked about fluorescents specifically.  The light is the result of high-voltage excitation of the gas in the tube.  Everything else you said was correct, though.

The nice thing about fluorescents is that they produce a much greater amount of light for the same energy an incandescent draws.  They are therefore more energy efficient than incandescents.  However, as everyone has pointed out, as long as they're on, they draw power.

To address the original question, yes it takes a bit of a shot to "ignite" a fluorescent tube, but it is more economical to turn them off when not needed.  The ignition energy is pretty small
[sniper]

My bad, didn't read the post well enough - Thanks for clarifying.  Hmmm, dunno too much about Florescents, but I'm assuming that you WOULD use slightly more juice energizing the gas, to turn it into a luminous substance.  But, this increase of energy is minimal compared to the extended use by leaving it on.  "Off" is always better for saving $$$.

[brown]Evil J~[/brown]

To save energy you must: One, teach as a Profesor at a very left wing college or university. Two, get put off by society because they're not becoming socialists fast enough for your taste. Three, move to wilderness and living in a shack. Four, make a sh^t list and mail them items you put together at radio shack.


Now, if we could all follow this example....[;)]

Oh, by the way... Get a qupy doll if you can guess who this is..

the una bomber

You don't save energy by keeping them on, you save money.

Large offices save money by keeping them on because the bulbs last longer, therefore they don't buy as many bulbs.

In addition, since the bulbs last longer they don't have to pay as many people to go around changing the bulbs and they save more money.  

The in rush current puts stress on many things electrical and electronic.

Just like you don't want to turn your t.v. or your computer monitor on and off a whole bunch times unnecessarily, you don't want to flip the fluoresants on and off if you don't have to.

You do know that they can make incandesants that will last your lifetime and they aren't that much more expensive.  Thomas Edison's house in Florida has lightbulbs that have been burning for something like 60-70 years without burning out.  But how would they sell light bulbs?

[sleep] CANDLES!!!

ok maybe you are the people to ask, I've been living at my current place 3 years and havent figured this out (I have free electricity, don't care!) anyway at 10 every other night or so this 40 floor or so office building across the street turns off the flourescent lights on three floors (not 3 consecutive ones, just kinda randomly) at once for only about five seconds then they flip them back on and another three floors go out they go back on and another three and so on for just maybe a minute or so. This is really weird. Secret illuminati (no pun!) communication system? Is the p-funk mothership going to descend on my town and drop a funk-bomb?[whacko]

Um, yeah you figured it out...George Clinton is going to come to your house and abduct you, and take you to his Funk-HQ on Mars [>:/]

Can't put anything past you.
[brown]Evil J~[/brown]

When I was in Toronto a few weeks ago there was an office building outside my hotel that was doing that.  Couldn't figure it out then either.