[Greenbuilding] [BULK] Real cost comparison of xenon verses fluorescent verses LED lighting

Sun May 27 11:16:53 CDT 2007

Lawrence's answer is very thorough and knowledgeable. Some additional thoughts:

I was at an interesting IES event the other day on lamp efficacies 
and the upcoming bans on incandescent lamps. In a discussion with one 
of the presenters afterward, we talked about not just efficacy but 
applications -- e.g. while a halogen might be far less efficacious 
than a CFL, a halogen task light  might have the ability to placed 
close to the area needed, and hence need less lumen output, than a 
more distant but energy efficient ambient source. This was an 
interesting take on things, especially since there aren't many energy 
efficient task lights out there.

We also discussed overall life cycle costs -- comparing the total 
cradle to grave impacts of, say, 100,000 hours of incandescent, LED 
and CFL lighting including production and disposal impacts. None of 
us knew of any such analysis. (One question was whether the mercury 
in fluorescents and CFLs was offset by the decreased mercury output 
resulting from less energy consumption -- dependent on the energy 
source, of course.)

The LED fixtures I've looked at so far (including at LightFair and 
the ICFF in the past few weeks) are still not there. I was looking 
for recessed lights and for task lights/bed reading lamps. Permlight 
is getting close with their new recessed fixtures. I saw some 
promising task lights from Pablo and Koncept at the ICFF, but the 
output was still fairly low and the distribution too narrow.

I'm looking to design some LED fixtures for my Fire & Water lines 
soon. I'm still researching and watching the technology evolve.

David
DAVID BERGMAN ARCHITECT / FIRE & WATER LIGHTING + FURNITURE
architecture . interiors . ecodesign . lighting . furniture
bergman at cyberg.com    www.cyberg.com
241 Eldridge Street #3R, New York, NY 10002
t 212 475 3106    f 212 677 7291

At 10:51 PM 5/22/2007, Lawrence Lile wrote:

>Well, LED's are hyped as very efficient, BUT they are emerging
>technology, and vary widely.  I just specified an LED lighting system
>that was a dismal 20 lumens per watt, no better than a halogen bulb,
>whereas in the lab there are LED's that are 150 lumens per watt, better
>than anything else out there. The ones we are using are outrageously
>expensive (this was for a special industrial application)
>
>I think that LED's will become more standardized and consistent (and
>AFFORDABLE) over the next five years, while I have an LED flashlight,
>I'll be waiting a while before I put LED's in my house. A quick survey
>of some sites showed numbers like 40-70 lumens per watt, pretty dismal
>compared to T-5's and T-8's.  But, LED's have no mercury and won't need
>replacing for dozens of years. At 4 hours per day, a 100,000 hour LED
>should last 68 years. Deed it to your grandchildren in your Will.  Here
>are some "vaporware" LED's from GE: lots of hype, no specs on lumens per
>watt, can't buy 'em yet:  http://www.lumination.com/product.php?id=56
>
>T-5's are pretty good stuff.  T-5 lamps with an efficient electronic
>ballast will be one of the most effective sources of light you can get
>today, and the price is not bad either.  A typical bulb might be 100
>lumens per watt initial lumens.
>http://tinyurl.com/24dvmq
>
>Low mercury T-8's with a good electronic ballast can reach 107 lumens
>per watt initial lumens, one of the best available technologies. This is
>what I just put in my house.
>http://tinyurl.com/ynmauc
>
>
>Xenon lamps, that I have seen, are no more efficient than regular
>incandescants.  Add a low voltage transformer at maybe 90% efficient and
>they are worse.  20 lumens per watt at best.  Probably have great color
>rendering index, so if you really need to see colors well, these are the
>bomb.
>
>
>
>Lawrence Lile, P.E., LEED AP
>
>-----Original Message-----
>From: greenbuilding-bounces at listserv.repp.org
>[mailto:greenbuilding-bounces at listserv.repp.org] On Behalf Of Leanne
>Rellstab
>Sent: Tuesday, May 22, 2007 8:42 PM
>To: greenbuilding at listserv.repp.org
>Subject: [BULK] [Greenbuilding] Real cost comparison of xenon verses
>fluorescent verses LED lighting
>Importance: Low
>
>Does anyone really know how energy savings compares between xenon,
>fluorescent and LED lighting.  Several websites endorse a quality, low
>mercury content T-5 fluorescent bulb as a good choice.
>
>I haven't found much on web sites about how much energy the transformers
>
>use, only what the bulb wattage use is for xenons and LEDs. Transformers
>
>seem to be the weak link in these lighting systems- is that right?
>
>Embodied energy and pollution byproducts during manufactoring is also a
>factor in selecting a lighting type.
>
>Would any light experts or someone one with hands experience care to
>comment?
>
>Leanne and Doug
>
>
>
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