Hi
I have a mains wall light which has ten 10 watt halogen bulbs on it and it says on the back its 0-105W. Is it possible to connect a dimmer switch to this light without havin to include a transformer. If i can what sort of dimmer switch would you recommend?
Many thanks Bre
-- brendonavoo69
That doesn't look right.
Are the bulbs mains or LV?
You need a suitable dimmer. If LV, you'll need one suitable for this. If mains, make sure it is rated at least 25% above the wattage of the fitting.
if 12v halogens, no. If mains, yes, but it wouldnt be a very smart idea. Switchbank is a much better option, unless you actually enjoy heating your house up during the hot summers.
NT
Eh? While a dimmed dimmer produces *some* heat, the dimmed bulbs produce much less than when on full. Total end result *less* heat. Would also be the case if using a simple resistive dimmer if such a thing existed.
That's a standard rating for electronic transformers. Is it an electronic transformer?
If the transformer says "dimmable" on it, then yes. Most nowadays are dimmable, but many older ones weren't.
A dimmer which is marked as suitable for electronic transformer loads. MK do a good one. You may have trouble with cheap dimmers.
Andrew Gabriel tested a 500w halogen lamp dimmed to the output of a 40w bulb, it was eating 300w. Dimming produces heavy loss of efficacy.
10x halogen bulbs is normally 200, 350 or 500w, most often 500. Diming to give half brightness output will produce very little power reduction. OTOH a switchbank would mean half the power for half the output. Thats a difference of 250w for a 500w system. And thats a fair bit of heat, especially when the day is already very hot.And guess what, you get to pay for that discomfort on every leccy bill. Halogen downlighters on dimmers are one of the most energy inefficient lighting methods you can find. Non-downlighting on dimmers isnt good either.
The cost of lighting like this is surprisingly high. Google if wished. In short, dimmers are not an intelligent fashion.
That would be even worse, as not only are the bulbs running at low efficacy, but the dimmer is already pouring out heat.
NT
Not arguing that - simply that a dimmed bulb produces less heat than a full on one.
But less *in total* than a full on lamp.
Well, 300w versus 40w means not really. If you have a 500w lamp and want a 40, people with a dimmer will dim it and use 300w, people with no dimmer wil either put a 40w in or get another lamp with 40w so they can use either. So IRL dimmers waste a stack of power.
But less *in total* than a full on lamp
Same principle as above, 300w in the dimmed bulb plus another 100w in the dimmer versus a 40w bulb.
The answer depends on exactly what youre comparing, but in the real world the alternatives are a dimmed 500w or a 40w.
NT
I'd say the 500 watt halogen is a special case designed to make a point. But even if the difference in heat is tiny, it still can't be more than at full belt, as implied.
They're not for most people. A dimmed 500w multi-lamp fitting will look more attractive than a 40 watt bulb in most rooms. This sort of lighting is for effect or mood - not efficiency.
If you want to save money use CFLs - if you can stand the look of them.
Had a look at this the other day with 20W capsule halogen bulbs, dimming them to half brightness (subjectively) they still used 80% of the power used at full brightness. Dimming them more would give even lower efficiency.
Nah, that's just poor lighting design, of which there are many examples, especially in new builds and refurbs. Do you have halogens on dimmers? ;)
Some are very acceptable, especially when combined with a small amount of halogen where appropriate for task lighting. Which types and brand CFLs have you tried?
cheers, Pete.
All filament lamps behave the same way in this respect. The equations are
efficacy/EFFICACY = (volts/VOLTS)^1.9 efficacy/EFFICACY = (filament temperature/ filament TEMPERATURE)^4.52
inferred rather than implied
Youre mixing up 2 different issues there. If you want a multibulb light you have 2 choices: fit 10x 10w bulbs or 10x 50w and a dimmer. Good practice does not mean compromise on looks.
best kept for another thread.
NT
I would find such a fitting nothing less than immoral.
Christian.
Perhaps most house lighting is - and always has been. A naked fluorescent strip light in every room (which would be painted white) would be the way to go if you really care about efficiency.
Or a big dish to concentrate and beam in moonlight. Really though I agree with Christian on this, fwiw. Dimming instead of using lower wattage bulbs is not a particularly smart option.
NT
So you're going to install several different wattage lamps along side each other to give near the flexibility of a dimmer? Come off it. I've got 8 lighting circuits in the living area all on dimmers. To do anything near the same using switched lower wattage bulbs would a) cost a fortune in hardware b) look unattractive with all the extra switches and lights c) not possible anyway
The amount of energy my lighting consumes is peanuts compared to all the rest I use, and I'd rather make savings elsewhere than compromise the looks.
No need. In practice people only want 2 or 3 brightness levels, and this is easily achieved by switching on different lights. These days we usually have at least a few lights in each room rather than one, so its usually simple to achieve. Bear in mind it only takes 2 bulbs to get 3 brightness levels.
If you have 8 circuits all you need is a switch on each, and you have an assortment of illumination levels.
I have used dimmers in the past, and could never find any real usefulness in them. Any nice lighting scheme has enough lighting overlap that one can select various light levels without getting patchy lighting. But I know they remain popular.
NT
5, if you include series operation, and off.
Owain
Lighting to me is more than just about achieving 'levels' in a room.
If you have 8 dimmed lighting circuits just in your living area, I think you might find that your lighting energy is far from peanuts. It could be well over 50% of your electricity consumption. Unless you have electric heating, most household electrics either use very little, or use large amounts for very short periods.
Christian.
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