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Don't Ban Tungsten – IR coated 12v halogens |
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| The following
has been kindly sent to us by a physics teacher from West Sussex. Please
note that the opinions expressed are those of the author, and that NVM
Digital does not endorse or disapprove of any of the products types discussed.
If you would like us to post your comments (with or without your name - optional) please send them, with a suitably relevant title, to info@nvmdigital.com. We reserve the right to decide whether or not to post comments received, and to edit out all trade names, personal names, and potentially sensitive or offensive material. Dave Mulligan 10/3/07 |
Don't Ban Tungsten – IR coated 12v halogens
Thank you for your article on CFLs vs. tungsten. I too am appalled at the ignorance around this subject and the stupid idea of a ban on tungsten lamps that is being floated at the moment.
I also have failed to find any info. on embodied energy in the manufacture of CFLs.
However, I want to bring to your attention a positive development in tungsten technology: IR coated 12v halogens.
These lamps are approx 40% more efficient than standard 12v halogens (20W = 35W standard halogen), and are longlife (5000hrs+) closing the gap with the inflated claims made for CFLs.
There is, I believe a case for banning GU10 mains halogens - which are inefficient and have a short life. They have mainly been marketed strongly as they simplify the design of lightfittings as they do not need a transformer - but modern 12v halogen transformers are now very small, dimmable and soft-start - extending the life of the lamps considerably. Unlike the electronics in CFLs, 12V halogen transformers can last as long as the fitting/installation. Furthermore, recessed GU10 downlighters are a fire hazard. This is significantly reduced for IR coated 12V halogens.
A rough example, from personal experience:
50W 240V/gu10 halogen = 35W standard
12V halogen = 20W IR coated 12V halogen
i.e. about 60% energy saving without
all the problems of fluorescent colour rendition, manufacture and disposal!
Also in my experience you really
do get the quoted lifetime (5000 hrs) with 12V halogens (we have not had
to replace a single one in our living room in 4 years).
Furthermore you can dim them easily
- making further savings. Apparently at approx. 80% full power lamp life
is extended considerably.
They also retain colour and intensity
well over their lifetime - not something you can say about CFLs.
A further point about lighting. We mostly want light to land at key points in our house - tables, where we sit, the pages of our book, stair edges, door handles, paintings etc. It should be easy to replace all of the tungsten lamps in a room with CFLs and measure the lumens per cm2 at key locations. I think you would find that the quoted lumens-per-watt for CFLs is irrelevant because of their poor directionality - how much of their quoted light is lost in the fitting or directed away from where we want it? As a starting point we need to know lumens per watt per cm2 at a standard distance.
(Physics teacher, West Sussex)
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