[quote author=Lectrician link=1092214325/0#11 date=1092329564]Dont like LV then BAS
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No - I do like LV. It's ELV that I don't like
Quote:- 90% of heat fires backwards from the bulb, so cool to the front.
This is to do with the lamp design, dichroic vs PAR, not the voltage, and you can get both types in mains lamps, so you have the choice. In a ceiling, heat coming out forwards is not usually a problem, whereas a lot of heat going back into the luminaire might be, so this choice is a good thing...
Quote:- Light colour rendering is excellent, pure white.
There's not a great deal of difference - if you didn't have both types next to each other to compare, then I don't think you'd ever look at a mains halogen and think "oo-err, that's not very white". They are
all a great deal better in this respect than traditional incandescents.
Quote:- LV lamps last longer
Not always true. Different manufacturers at different price points quote different lives. In both cases it's a spread of lengths with a lot of overlap. Some mains halogens are longer lived than some 12V ones, and in a lot of cases the differences are so small that if you were concerned about them you'd not be using halogen lighting in the first place.
Additionally, dimming can be troublesome - you have to select an appropriate dimmer and you also have to ensure that the transformer is suitable for dimming - more complication, not less. And even then, there's a reasonable chance that the transformer will generate an annoying buzz when dimmed.
And good quality transformers are not cheap.
Finally - future proofing. LED lamps are getting better and cheaper all the time - they're already up to 20-30w equivalence, and the hugely increased life already more than compensates for their higher price. With mains luminaires you can just plug them in. With 12V ones you'll run into problems with underloaded transformers, as the actual consumption of these lamps is in the 1-2W range.