How efficient are fluorescant tubes ?

[#1]

Can anyone answer the following conundrum ?
When I was a kid, I was taught that it takes more electricity to turn a fluorescant tube on than to leave it running all day.  I suspect that was an urban myth. but I have always lived by that premise.
Does anyone know the truth ?  Can anyone disabuse me from this strange theory ?
Also, does a 100 watt fluorescant tube consume 100 watts all the time or again only when starting ?
The other worry is that they are very expensive and perhaps turning them on and off reduces their life.  Does it ?
As I have to be more enrgy conscious now, I want to know whether to turn these tubes on and off or whether to leave them running. 

[#2]

Flourescent lights use a starter to pre-heat the cathodes and provide a high voltage 'spike' to strike the arc required to make them work, this does use more power than when running but not 'hours worth' as often claimed.  Starting a Flourescent light probably uses as much electricity as as few seconds of continuous operation, each starting cycle will also reduce the life of the lamp though this effect is significantly reduced when electronic ballasts are used.
Some potentially useful information here: http://energy.gov/energysaver/articles/when-turn-your-lights

[#3]

you can get led versions of most tube lights now so it might be worthwhile checking to see if you can replace yours with one, sure the led tubes cost more than the fluorescent tubes do but they use significantly less electric and don't require a starter either not to mention they don't suffer from the same epilepsy triggering flicker common with many fluorescent tubes 

[#4]

Quote from: nanotm

you can get led versions of most tube lights now <snip> use significantly less electric..

and they should last longer, contain less harmful substances etc.  L

[#5]

I've looked at the output of LED's per watt recently and they don't seem any more efficient than fluorescent tubes (or CFL's for that matter).
More expensive too, certainly vs standard tubes.  
For now my main kitchen (and garage) lighting will remain as standard fluorescent tubes.
As for the pollution issue, I'll await some more information on what's involved in the manufacture of LED's.

[#6]

well yeah and a decent make will have a 5 year guarantee as well but your talking about £25 quid for one, and possibly needing a different enclosure (depending on the make /model of the one you currently have)  so it could be an expensive swap hence why I said look into it, then again the EUP is planning on making the sale of traditional fluorescent tubes a thing of the past just as they did with incandescent bulbs ....

[#7]

Quote from: nanotm

the EUP is planning on making the sale of traditional fluorescent tubes a thing of the past

Really? Can you translate EUP and provide a link please to inform us.
There are definitely plans to phase out older inefficient fluorescent lighting in street lamps as there are much better alternatives for such high-output uses, but in domestic use that is a surprise.  

[#8]

Quote from: HPsauce

I've looked at the output of LED's per watt recently and they don't seem any more efficient than fluorescent tubes (or CFL's for that matter).

Not sure I'd agree, LEDs should be more efficient on average - in my experience an LED bulb runs a lot cooler than a CFL, the heat is pretty much a measure of inefficiency.
Don't forget, one of the reasons that the inventors of blue LEDs got a Nobel prize is because their invention contributes to potential lowering of future CO2 emissions because it allows more efficient lighting to be developed.

[#9]

Of course blue lighting requires a very high temperature in a traditional incandescent scenario, or heavy filtering, so that makes sense.
Remember, early LED's were just red so not much use for general lighting.
Have read on the packaging of lumens vs wattage; you'll be surprised.
By the way my LED bulbs get quite warm.
But yes, overall I think modern LED's are somewhat more efficient than CFL's though pretty much in line with fluorescent tubes.
Edit: This article suggests LED's have the edge by maybe 30% (at a price) http://www.premierltg.com/should-you-replace-your-t8-fluorescent-lamps-with-t8-led-tubes-2/

[#10]

My LED bulbs get distinctly warm but I nearly burned my hand some time ago when I went to remove a CFL just after switching it off - it was a LOT warmer than my current LEDs (individual ones may vary, I usually look for ones with a good lumens/Watt ratio).

[#11]

Yes, I'm no fan of CFL's, but as above I'm not yet ready to dump my fluorescent tubes.

[#12]

environmentally speaking its the mercury that makes the difference since its not used in led bulbs, but is used in fluorescents,
EUP is European Union Parliament, its one of many proposed legislative changes on the cards to do with energy saving for future directives to be issued from like the ones already issued to lower the maximum wattage of vacuum cleaners and stop sales of incandescent light bulbs ....

[#13]

Surely they haven't blocked you from accessing the relevant data that you could link to,
since that would be moderately recent & not as ancient as some of your former missing links
Then others could Dot the I's & Cross the T's to make an informed decision
Highlight ==> Right click ==> Copy & Paste
Or
Highlight Drag & drop
Or
CTRL+C to copy & CTRL+V to paste
Several options available

[#14]

Quote from: nanotm

you can get led versions of most tube lights now so it might be worthwhile checking to see if you can replace yours with one, sure the led tubes cost more than the fluorescent tubes do but they use significantly less electric and don't require a starter either not to mention they don't suffer from the same epilepsy triggering flicker common with many fluorescent tubes

Flashing lights are relevant at 5-10Hz and affect only about 3% of epilepsy sufferers.
So a frequency of 50-100Hz(?) wouldn't be relevant.

[#15]

Quote from: w23

My LED bulbs get distinctly warm but I nearly burned my hand some time ago when I went to remove a CFL just after switching it off - it was a LOT warmer than my current LEDs (individual ones may vary, I usually look for ones with a good lumens/Watt ratio).

Interesting point about  LED's getting warm.
We have a lamp using LED'S that gets very warm they are rated at 240v / 12v but a few weeks ago we had another lamp with a  G4 bulb in that also got hot and the bulb had blown so I purchased a small transformer and a replacement 12v  led that clearly stated a transformer had to be used.
Result, a light as bright as the G4 bulb with no heat generated and it takes so little energy it does not even show on my energy monitor.
The LED is rated at 12v  1.5 amps.
Total cost was under a tender.