Flourescent lights


#1

My school is making big efforts to be environmentally friendly - lots of recycling, and can we turn the lights off when not in use please?

Trouble is we’re using flourescent tubes, and having a bit of a difference of opinion. I had always believed that these lights were very efficient once turned on, but required a lot of energy to start. So once they’re on you leave 'em on for the rest of the day.

Does anyone have any input?

Thanks


#2

Yes, you are right, but trying convincing the average bushiban owner :wink:

I think the startup uses about 20 minutes worth of juice, so less than 20 minutes, leave 'em on.


#3

You know. About a year ago I tried telling some of the other foreigners I worked with that it cost more money to turn the lights on and off than it did to leave them on and all of them thought I was full of shit.
Glad to see that somebody else knew what I was talking about. Good luck convincing your boss though…


#4

Can’t imagine what they are … are they used in breadmaking?


#5

Sorry, but I disagree: when a light bulb is switched on a very high current will rush through it - but only for a fraction of time.
(This is actually the reason why bulbs usually only blow when you switch them on.)
Because this is such a short time you will not be able to notice the higher consumption and thus it’s a myth that leaving the light on saves energy - rather the opposite.

The same applies to fluorescent lights which need a starter to produce a very high voltage to trigger the, well, light. Again this happens for a very short time only after which the power consumption is “stabilized”.
Fluorescent lights are around 10 times more efficient and have an increased life expectancy of 6-8 times compared to bulbs.

I would agree not to switch lights on and off in 5 minutes intervals, but for a longer break it surely makes sense.


#6

There’s a detailed discussion of this at lightingdesignlab.com/articles/s … escent.htm

The recommendation for a general cutoff point given there is 15 to 20 minutes. This has to do with reduction to the life of the lamp caused by switching it on and off, not with energy savings.


#7

Well now I know. Thanks guys.

Iv allways bean pruod off my speeling, till I strated to poste heer. Three tims this weak sumone has cort me out. Once was my own email address!!

Probly stress due to arguments about when to turn the lights off.

fluorescent. asinine. chris@mail.lhvs.tyc.edu.tw Got it! Thanks