[Greenbuilding] compact fluorescent bulbs/Halogen

[David Bergman]

My understanding is that halogens are only somewhat more efficient 
than incandescent (with the IR versions being better) -- maxing out 
at around 20 lumens per watt and many of the cheaper ones only in the 
low teens -- and they are still fundamentally incandescent (i.e. work 
by heating a filament until it glows) and inefficient. CFL's get 
around 50 - 60 lumens per watt.

Additionally, most halogens do not last much longer than 
incandescents. You can get some specific ones (e.g. Ushio 
MR16's)  that last upwards of 5000 hours, but most do not. CFL's, if 
I recall directly, last around 12,000 - 20,000 hours.

Yes, halogens can dim (though you have to be aware of whether they 
are line or low voltage -- magnetic or electronic -- and have the 
appropriate dimmer). There are screw base CFL's that will dim, but as 
others noted they are not widely available and do not dim to the same 
low levels that incandescents or halogens will. There are also 
expensive dedicated (non screw base) CFL's that dim very nicely. 
(It's the electronics, not the bulbs, that are expensive.) Lower cost 
dimming is "around the corner," but will probably not dim as low as 
incandescent or halogen.

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 05:44 PM 3/21/2007, John Messerschmidt wrote:
>Hi,
>I was told by a lighting supplier that halogen lights are a good choice.
>They are more efficient than incandescent, although not as efficient as CF,
>but the color is acceptable, they direct the light more intensely, thus
>needing fewer watts, they can be dimmed, their lifespan is comparable to CF,
>there are models available that screw in.
>
>Of course he sells really nice halogen fixtures...
>
>Any opinions on that?
>
>
>
>-----Original Message-----
>From: greenbuilding-bounces at listserv.repp.org
>[mailto:greenbuilding-bounces at listserv.repp.org] On Behalf Of Lawrence Lile
>Sent: Monday, March 19, 2007 5:45 PM
>To: Ben Pratt; Greenbuilding at listserv.repp.org
>Subject: Re: [Greenbuilding] [BULK] compact fluorescent bulbs
>
>I've experimented with the "daylight" 5000K color temperature bulbs, and the
>4100K bulbs, but I prefer the "soft white" 2700K bulbs.  My wife described
>the 5000K bulbs as "The Death Ray" bulbs, but she seemed to like the 2700K
>types as they match incandescant bulbs better.  2700K are not that common,
>but i found them at Home Despot.
>
>--Lawrence
>
>________________________________
>
>From: greenbuilding-bounces at listserv.repp.org on behalf of Ben Pratt
>Sent: Sat 3/17/2007 8:31 PM
>To: Greenbuilding at listserv.repp.org
>Subject: [BULK] [Greenbuilding] compact fluorescent bulbs
>
>
>
>_______________________________________________
>Greenbuilding email list
>List info: 
>http://listserv.repp.org/mailman/listinfo/greenbuilding_listserv.repp.org
>List email: Greenbuilding at listserv.repp.org
>Managed by BuildingGreen, Inc. http://www.buildinggreen.com
>       publisher of Environmental Building News and GreenSpec(r)
>Hosted and archived by REPP / CREST http://www.crest.org