Disclaimer: I have a commercial interest in LED lighting technology.
CFLs or compact flourescent lighting has been around for quite a while.
What many people refer to as the 'spiral bulbs' are no different to the larger commercial flourescent tube lights in operation and design, just
shape and ballast is slightly different due to size. Pretty much any non neon tube flourescent light is a 'CFL' and all contain mercury, 5mg for
spirals upon production (it does decrease over lifetime usage) and more for larger or higher rated tubes. Plus any coal fired stations your country
Flourescent and incandescent bulbs have a design which is highly inefficient in most applications; a 360 degree radiation pattern. Sure they'll put
out 'XX' lumens in 360 degrees, but when you need it in a 120 degree field (e.g. desk lamp, downlight, torch) , you need a reflector, which usually
with cheaper designs causes reasonably high losses, 30-40% or more.
So in many applications, all that light you started with, 30% wasted already. Lumen per watt figure drops from a optimistic but respectable 60lm/w to
42lm/w and I havn't even got into the inefficiency of a spiral design - with a large area directing light into the adjacent coil.
Most high end leds are built with a 120 degree dispersion pattern outta the box. For most uses, this gives an immediate advantage in efficieny. The
numbers for high end leds are around 603lm, 5.4W, 120lm/w typical efficiency usage scenario, outta a 5mm cree xml cool white led. Already double a CFL
without factoring in reflector/direction losses for CFL. Sure the cost for leds is higher, but they pay for themselves in 2 years compared to
incandescents, and longer compared to CFLs once replacement costs and power usage are factored in. And they aren't easily broken by shock like every
other glass or filiament based bulb out there.
Flourescents create a usually high frequency, high voltage arc in a mercury vapour which emits a strong UV light. This is converted to what we see as
white light while passing through a layer of phosphour - the white layer you see. Problem is when this phosphor coating isn't even or has gaps around
arc areas or damage, it can emit highly harmful UV. This UV is used in germocidal lamps which do not have the phosphor coating. You can sometimes see
it on CFL spirals as the bases will have very brown plastic for very little heat - UV is used to cure plastic, the base of the spirals often show
premature UV curing/browning from leakage in this area. People with UV hypersensitive skin are burned by poor quality and UV leaking bulbs like
LEDs are not saints either as they are often constructed of Indium gallium nitride, which can be an irritant to your body.
However, cutting edge led technology means you get at least 50,000 hours before a 10% total output drop at horrible temperatures in worst case
scenarios. When designed properly this 10% lifetime will easily exceed 100,000 hours or much more in certain cases. Compare to 10,000 hours for most
spiral flourescents and you're laughing. This being said, the indium gallium nitride is sealed behind a dome and is only entered into the environment
during production and you would have to throw an led away. I doubt many current high end leds in commercial illumination usage would be thrown away in
20 years time, the power supplies will die first. The efficiency limit for a perfect blackbody radiator has been pretty much reached with current high
end LED tech, so they most likely won't get much brighter or much more efficient for the same die area in future as long as the laws of physics hold
Most consumer grade led technology is pretty much minimum cost, technology trickle down junk, inefficient, heat issues, poor circuitry
components/drivers, they often don't last - this doesn't give leds a good name. You need to build your own to really get high quality and long
lasting lighting systems unfortunately, many commercial designs at higher prices are also rather bad. There are a few notable exceptions but they are
far and few between..
In 1999, the California Board of Energy Efficiency commissioned a study and found that increased sales, increased productivity, increased wellness and
reduced energy costs resulted from companies using natural solor lighting instead of artifical light.
Flicker is a big issue for worker productivity. The original studies I read a few years ago I cannot locate anymore, however productivity loss figures
of up to 30% were used to demonstrate flourescent vs incandescent/sunlight. Incandescent has 60hz flicker but due to filiaments physically heating up,
they don't visibly or perceptably flicker. Flourescents are usually horrible with their flicker to me, as is colour rendering - they do come in warm
white which improves things from the alien abduction bluey white you commonly see. LEDs are DC constant current devices and in good driver designs
will not flicker in any way. This can be used to simulate sunlight very well and not cause productivity loss.
If I had to choose any light system to put in a deep underground base or inside my house, LED would win, hands down. Not changing a bulb in my
lifetime sounds like something I could see as being beneficial, to not only the environment but my sanity. Need vitamin D indoors? UVB leds have it
covered too. Only thing they can't do is heat your room up in winter, however at 10lm/w an incandescent leaves much to be desired that a good heating
system could do more efficiently.
I've tried to keep this as short as possible while hopefully being as informative as possible, you won't see these particular issues and information
condensed like this on wiki or anywhere else, so I hope you enjoyed it
If you have any further questions please just ask or search for the answer.