In my extension most of the new rooms will be having the small lights inset into the ceiling - but I don't know whether to do it with low voltage lamps or use the mains powered small lamps (Wickes currently are doing packs of 4 mains powered lamps for =A313.99).
Can anybody tell me of the relative advantages/disadvantages of going low voltage or mains voltage for this lighting?
Quigs
^^^^^^^^^^^^^^^^^^^^^^^^^^^ Gary Quigley See my build at
more bangladeshis
RT
Are you talking about halogen downlighters? If so, use LV.
You get much more light per watt of input power from LV. This is because they have short fat filaments which can by run at a higher temperature than the long thin filaments in mains lights. A hotter filament produces much more of its radiation in the visible spectrum rather than infra red.
LV bulbs also last much longer - you'll be for ever replacing mains bulbs.
One of our rooms have a light fitting using 4 mains powered GU10 bulbs and I can guarantee a bulb will blow every 3 or 4 months. Surprisingly the bulbs that have lasted the longest so far are the cheap twin packs I got from Poundland! If I fitted another one I'd pay extra go for a transformer low voltage type.
They're both horribly inefficient at general lighting, and won't meet the building regs requirements for lighting energy efficiency if they apply to your extension (I can't remember off-hand when they kick in on a building project). You should also fit fireproof caps over them so fire can't spread through the holes you make in the ceiling for them.
LV is cheaper to run in terms of efficiency and relamping costs, and has a wider range of different spec lamps available. Mains is cheaper at initial install time, but otherwise it's generally a disadvantage.
I would strongly suggest you think about a better lighting scheme altogether though. Using spotlights aimed at the floor for general lighting normally results some combination of very energy inefficient and rather poor room lighting.
Are the LED downlighters available yet? How do they compare on brightness and energy efficiency? I imagine that they can be fitted into the same fixture - that is they are GU10 spec. CM.
The building regs may require instalation of a certain number of "low energy" light fittings as a part of the build. The number required being dictated by the number of habitable rooms you are adding.
Note however that these fittings do not have to be the only fittings used... so you can make your ligting as energy inefficent as you want, so long as somewhere you can point to the required number of LE fittings to satisfy the regs. Even if the LE fittings never get used!
What the others said, plus:
12V will give a better colour spectrum than mains halogen - so a more natural "daylight" like light.12V is available with dichroic reflectors which will aid point 1 above, and will also result is less heat being projected forward by the light. (correspondingly, more heat being lost though the back of the bulb into the fitting and surrunding area)
Modern 12V transformers tend to be Switched Mode Power Supplies rather than actual transformers. Hence they are smaller, lighter, and more efficent. However they do produce more EMI that can be picked up in succeptable equipment like analogue cordless phones etc.
Roughly same efficieny as LV halogens. However, semi-conductors would be destroyed at typical LV halogen temperatures, so they're all much lower power, with resulting much lower light output. To make them look bright, the light is usually concentrated into a very narrow beam.
There are 7W compact fluorescents in this format now. In theory, they should give the same light as a 28W mains lamp, but that's probably reduced a bit as the tube and reflector combination is not going to be as effective as with a filament lamp, and they will be wide angle only.
Luckily no coffee anywhere near my screen :-)
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