Fluorescent tubes

Impossible is Nothing

I seem to remember being told in school physics lessons that switching a fluorescent light on and off uses far more electricity than leaving it on.

So that I can correctly inform the finance people at work who suggest lights should be switched off when the room is empty, can someone give a figure for the length of time it is okay to leave a fluorescent tube on? (Before it would have been more economical to have switched it off then on again, if you see what I mean?!)

[Deleted User]

I don't know but would like to too.

BO

[Deleted User]

Ditto these curly wurly economical light "bulbs"

BO

Moe

The figure of six hours rings a bell with me, not sure though.

bertie balloon

It's just a myth spread my people too idle to switch lights off. Just like leaving your PC on, leaving the Tv on standby etc. It makes better financial sense to switch off everything that's not being used. Obviously if lights are being turned on and off every 30seconds then you may have a point otherwise switch off. Our company have started switching lights off over lunch when people leave the office and have saved in the region of £500 a year.

FerrousFerret

A number of different points here (none of which I remember entirely):

Before the days of electronic starters the arc used to be struck using a high voltage spike, while this does require more energy than regular 240v, its not 6 hours worth (average fluorescent tube consumes around 50 Watts).

Fluorescent tubes used (I am talking 15 years ago now) not to take kindly to lots of switching cycles. What makes it more efficient is a combination of lower energy consumption and a much longer lifetime of the tube (10K hours v 1K hour) which offset the higher cost of the tube itself. I think that this 'it's better leaving the light on' may be based on this concept of shortening the lifetime of the bulb everytime you switch on and off.

Depending on where in the a/c cycle you switch things on and off, you can subject the equipment connected to large (x6 - x11) voltage spikes- which is perhaps a theoretical argument that you should never turn anything off.

<goes off to lie down as it's a long time since I had to think about stuff like this>

Jj

¦'oD

[rolls around, wheezing and clutching sides]

You probably won't believe me, but...


¦oD

I thought this thread title said "fluourescent PUBES"!!!

[Deleted User]

Are they a turn off too Jj?

Duck Girl

I hate flourescent lights. They have them in all my lecture theatres & they are flickery & buzzy & screechy & nasty

Impossible is Nothing

I don't have the guts to start that thread Jj - would be fascinating though...possibly...

Thanks all. Looks like I'll have to get on with it and smile while I turn the lights off.

Impossible is Nothing

Oh, and you have correctly spotted that my school physics lessons were more than 15 years ago. I am now a Master according to IAAF ratification...