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

[Lawrence Lile]

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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