I’m currently looking at replacing a couple of kilowatts of halogen lighting with LEDs. It’s currently 12V but the 240V fittings would cost very little.

What am I missing?

Bulbs the same price, equally efficient except that MR16 needs a transformer which will introduce losses, more bulb ratings available at 240V, dim-able bulbs more readily available at 240V, not need to observe a minimum loading on the transformer when you don’t have one.

Why would anyone use 12V MR16?

Thoughts please.

No-one have any heart felt opinions on this?

Not even going to laugh and point fingers at me for asking such a daft question?

the standard 50W GU10 draws a stupid amount of power, I’ll despair you the calculations but ten 50w GU10’s ran at 5 hours per day 7 days a week would cost you £107.52 (based on 12.8p kwh), ten 7w LED’s would cost you £15.05.

The maths speak volumes.

Is changing over that easy? You will have to replace all the low voltage wires to the new 240V fittings wont you?

About to fit 24 Led downlighters into a new open plan kitchen so will lurk with some interest in what others have to say…..

The 12V halogens were used over 240V halogens because the bulbs lasted longer (not sure why). 12v LED’s are simply available to use in those fittings. The is no advantage in using 12v LED’s over 240V LED’s, its just a case of buying something compatible with your fittings. My understanding is that if your buying new fittings anyway and intend to use LED’s buy 240V fittings to avoid having to use transformers. Hope that helps.

p.s. forget to say that 12V are obviously more suited to bathrooms/wet areas.

GeordieMick – that’s the starting point. I currently have 15x50W 12V halogens in the kitchen alone (not to mention two bedrooms, bathrooms, dinning room, toilet, hall stairs and landing) and I’m looking to go 15x 4 or 5W LED – but not sure whther to go 240V LED or 12V LED.

While the two (easy option) replacement 12V MR16 LEDs I’ve done so far (4.5W is sufficient by the way whatever the boxes say) are meant to run on 20W minimum rated transformers they don’t seem entirely happy (bit of noise/flicker on one of them). And they seem to be £10 a bulb.

There appears to be 240V to every light fitting and then a transformer per light fitting (in my kitchen at least) so a £2.64 240V fitting sorts that and the bulbs can be had for £8 – so £0.64 plus a bit of elbow grease.

The 240V option cuts the transformer so should be more efficient (no transformer losses) and more reliable (the bulbs are now more reliable than the transformers I hear) long term.

And there are more bulb options at 240V, particularly dim-able and higher power (eg 9W) options.

Phil – sounds about right.

Thanks all.

igm – I’m in the same situation, 18 50w 12v MR16 halogens in the kitchen plus a further 7 in the hall and 21 upstairs although bathrooms aren’t so important as they’re not on for that long.
AFAIK there’s no reason to stay with 12v whatsoever.
Just bought 4 4w GU10 led to try. Simple job to fit as far as i can tell – just switch the power off, remove halogen bulb, pull transformer out of the hole and undo the connection to the 240v, connect GU10 holder and lead (about £6 for 10 off eBay), connect led light.
Just waiting for my GU10 leads to arrive so I can try them out. Spur of the moment purchase while at Costco, 2 x bulbs for £11 (on offer).

Sharkbait – thanks, I have a Costco card somewhere.

About to fit 24 Led downlighters into a new open plan kitchen so will lurk with some interest in what others have to say…..

Being a commercial electrical installation business, we have installed all sorts of LED’s. Here’s my take on it:

1: Replacing 12v? If each fitting has its own transformer, replace with 12v LED and replace the transformer with an LED driver. Old wire wound halogen transformers are better suited to take the low wattage required by LEDS, electronic halogen transformers require a minimum amount of watts before they operate. OR,

2: Convert to 230v. This would usually require replacing the 12v fitting with a GU10 and the wiring going to it, but also take into account the type of LED bulb you are fitting in relation to the width of fitting. While the LED bulbs are designed to fit into GU10 fittings, a lot of the fittings have spring clips that hold the fitting onto the ceiling. Depending on your ceiling thickness(sometimes two layers of plasterboard as a fire barrier) this my force the springs in and may fowl on the bulkier type of LEDS. Also consider how much depth between the floor above and ceiling below along with fire barrier ratings.

3: If the 12v’s are not supplied by an individual transformer, have fun ripping up floorboards and the like looking for it and the junction box.

4: Retro fit Vs purpose built LED fitting. Retro fits are designed to fit into Halogen, All I can say that get a good quality LED bulb from GE/Sylvania/Osram/Philips/Toshiba/Samsung. These may be twice the price, but the light output is better.

As for purpose built fittings, retro fit LED bulbs are restricted width wise because they have to fit into existing 12v/GU10 fittings, so you may get three or four LEDs per bulb. Purpose built fittings like these ones are wider and as such have more LED’s in them which does improve light output further. Once again they are a little more expensive, but having installed these ourselves they are among the best we’ve used so far.

GU10 bulbs don’t last more than 500 hours in reality, you’ll be changing them forever and a day. LED’s last on average 25-30K hours. It may be more of an initial outlay but LED”s generally do fit into the ‘fit and forget’ category

I changed 16 in my house last year and I’m saving about £1 an hour when they are all on…

This prompts me to ask. Are these LEDs a feasible option for lighting a whole room as opposed to under cabinet location?

I have a fluorescent strip luminaire in my kitchen but the light, while adequate, is not of a great ambience and I was looking for an alternative.

he standard 50W GU10 draws a stupid amount of power,

About 50 watts at a rough guess 🙄

Dobbs you are a genius

Careful replacing halogens with led as lots of electronic transformers are not compatible….

You can remove the transformers. wire in GU10 lampholders (about £2 each) and fit retro fit GU10 LED lamps. 6W LEDs are a credible 50W replacement.

You can get retro fit LEDs with MR16 bases, but they don’t like transformers very much.

Dimming. You need dimmable LEDs AND a LED specific dimmer or replacement LED dimmer module (Aurora AU-DSP400X?) You can’t dim normal LEDs.

The biggest reason for people using 12V MR16 lamps is that they simply like the light they give.

If you are replacing with cheap LED’s make sure you try one first as I think you are likely to be very dissapointed. A good quality LED replacement lamp that you can really compare to a 50w lamp costs around £25. Cheap LED lamps are not very bright, and generally a narrow beam so you need more of them.

You’re a bit out there on your prices. 6W retro fit in coolwhite, daylight or warmwhite. Very good output we’re getting for £10.50 plus VAT. Prices are tumbling.

oldgit have you got a link to those as I would be pretty interested. The only ones I have seen at that sort of price even recently are not the sort of thing I would really want in my own home. Used some Aurora 7w dimmable ones recently and they were definately around £25 even with enough lamps for 8 flats. Very good quality light though.

ajc.
Kosnic 6W
They do a dimmable in 5W, but we’ve been waiting ages for the 6W dimmables to arrive.

Aurora are dearer, and you’ve just said dimmable. £20’ish sound about right for those. Were they the longer LEDs with the heavy? metal bodies.

I dont know if anyone’s mentioned the “strobe” effect yet?

Basically when we changed from 12v mr16s to 240v led’s there’s a weird strobe effect with fast moving stuff. Now normally that wouldnt bother me in the slightest – but in our shower the water flowing from the tap / shower head either looks like lumps coming out of the tap or that the water is moving upwards. I dont know if anyone remembers that thing in old westerns where the wagon wheels appear to move backwards- well similar effect.

Anyways that’s a small “weirdness” to pay for a really noticable drop in the bills. Just do it.

We’ve changed out kitchen (x8), bathroom(x6) and ensuite (x6). We’ve a mix of hong kong cheapos (with lots of doa’s) to £12 a pop Philips ones.

The 240 volt LEDs are better as you say you don’t need a transformer, however they make 12v equivalents so that people can just swap them over as some people may not be confident enough to remove the transformers Philips I’ve found are by far the most advanced bulbs they’ve invested millions in them you can tell there a better quality when you handle them

As with most things, this is a subject that gets more involved the more you get, err, involved. I won’t begin to pretend that I’m an expert on this subject, but I’ve worked on projects with friends who are, and they’ve been installing very expensive LED lighting systems into large hoses, and in a nutshell, it’s a bit of a science.

As I say, I don’t know much, but I’ll tell you what I know………..

Halogen.
12v MR16 gives a nicer light than 240V GU10. There’s not a huge amount in it, but it’s a difference all the same. GU10 used to have a habit of tripping breakers when they “blew”. They would also kill cheap dimmers sometimes when they blew. They now tend to stretch the filament over a “pinch” in the lamp glass which stops them shorting when they blow. Lamp life can be variable with both. In the case of 12v lamps it’s dependant on the quality of the transformer and whether it “soft-starts” the lamp. GU10’s are hard started all the time, which is when they are most likely to blow.
If you fit a good quality dimmer (not the trash you pick up at B&Q) like Lutron, you will enjoy the benefits of virtually never having to replace a lamp, and you will be saving money because you aren’t running the lamps at 100%.
I have a kitchen with 22 12v halogen lamps and I’ve replaced 2 in the last 3 years. They seem to last indefinitely.
When you run the lamps at 90% you’d be hard pressed to see the difference in light level.

LEDs.
Oh God!
Okay, this is maturing technology and things are changing all the time, so in a few months the situation could be completely different.
Lights have a colour temperature, basically how warm or cool the colour is. Red at one end of the scale and blue at the other. A cool light will be blueish, and in the case of fluorescent lamps we’d call them daylight tubes.
Incandescent lamps (like 12v or 240 volt halogens) are often described as having a warmer colour, especially when run at less than 100%. in our homes we generally prefer a warmer colour of light.
Some science….. but don’t shoot me if I get a detail wrong here..
LEDs produce white light using a trick. They are basically blue LEDs and a yellow phosphor which when excited by the LED produces a wider range of colours. But the thing is that when you look at the light spectrum produced by an LED light, it’s quite “lumpy” when compared to a regular incandescent lamp.
in a nutshell, a cheap LED lamp may have the right colour temperature, but the light it produces looks weird.
This is because it’s producing more or less of certain colours and our eyes can sense this.
It’s known as the colour rendering index (CRI). the index goes from 0-100 with 100 being a perfect spectrum of light. The higher the number the better.

To get a higher CRI you have to spend more money. Also, the higher the CRI the less efficient the lamp becomes. So the more expensive lamps with good CRI are actually slightly dimmer. So to produce the same amount of light as regular 50W halogens, you need more of them.

Dimming.
I believe that no house should be without dimmers in at least the main living spaces. Having the “big lights” on full whack all the time is not nice. Others may feel differently, but that’s just my view.
When you dim Incandescent lamps (Halogen, good old bulbs etc) they change colour, becoming redder as they dim. We as humans are used to this and we like it. It gives a room a warmer glow.
LEDs do not change colour as they dim. It’s not a criticism, just an observation.
Some LED lamps/fittings are not dimmable, because they’re cheap.

Don’t forget that if you install or alter LOW VOLTAGE light fittings (not the lamps) and they’re not “pre-made” sets, then the work will need signing off by a registered sparks or building control.

It’s a bit of a minefield, innit?
Dunno if my ramblings are of any help, or even understandable, but hopefully they are of help.
Please feel to set me straight if I’ve made an error.

Griffster.

Some LED lamps/fittings are not dimmable, because they’re cheap.

Not quite they are either dimmable specific or not.

If you are starting from scratch and want LEDs, then look at the type like Auroras AU-FRL903 range. These are LED fittings, not LED technology crammed into an old style lamp.

I’m not sure. If it’s not a price issue, then why bother to produce dimmable and non-dimmable specific ranges? Perhaps there’s another reason. Either way, if price isn’t an issue then I don’t really understand why anyone would specifically want a non-dimmable fitting?

I wholeheartedly agree, and I should have mentioned it in my post. Retrofit LED lamps are not really the way to go. Specifically, they can have issues with keeping their LEDS and electronics cool which could impact the life of the lamp.

Edit.
Ah yes. Actually a 30% price difference between dimmable and non.
http://www.energybulbs.co.uk/products/LED+Light+Bulbs/LED+Downlights+%26+Combinations/Integrated+LED+Downlights
Neither are “cheap”, but it’s fair to say that LEDS are non dimmable because significantly they’re cheaper.

I’ve been looking at this recently. I swapped out our kitchen 12v MR11 halogens for LEDlite 230v GU10 LED spots (from TLC). They’ve been reliable so far (but only about 9 months so far).

However, have since realised/read that by using GU10’s you’re not avoiding transformers, you’re just packing them into a very small space on each and every bulb. I reckon GU10 LEDs are going to prove a lot less reliable than low voltage (as Griffster has just pointed out)

Next time I’ll fit either purpose built fittings or a single transformer per circuit.

As everyone else has said – buy good bulbs

I believe that no house should be without dimmers in at least the main living spaces

I’ve actually taken out the dimmers I fitted in our kitchen and in the living room we just use them as on off. Better than dimmers are >1 circuit. One set up for ‘mood lighting’, a second that adds general light, plus probably a third that adds task lighting (table lamps on 5AMP sockets etc) That’s what I’m planning for the new place at the moment.

Better than dimmers are >1 circuit.

Absolutely! You’ve taken the dimmers out possibly because you have just about enough light on 1 circuit with them full on. And you’re quite right to be planning multiple ccts. This is the basis of “mood” lighting.
At home I have 1cct for overhead worktop lighting, 1cct for overhead peripheral downlighting and 1cct for under unit lighting. That’s the kitchen. I then have another cut running the 5amp sockets for “accent” lighting – table and standard lights etc. There are 2 other ccts which aren’t dimmed at the moment, but will be when I do a spot of re-wiring.

Running the whole lot (and this is where the magic starts) is one of these…..
http://www.lutron.com/Products/SingleRoomControls/GrafikEye3000/Pages/Overview.aspx
There’s only 5 buttons – off and 4 scenes. So you just pick your light levels for each cct for each scene and then you’re done. Just press a button and it’s all done for you.

Have fun designing your system.

I remain to be convinced by things like that Lutron dimmer. They’re £600, and the Futronix equivalent is still £400. If you’ve got the light outputs correct you don’t need the dimming and can get the same effect with a 4 gang light switch for less than £15.

My question about ‘all in one’ LED fittings – how do you model the light levels? Is there any free (or cheap) software to do it? With bulbs you take a guess and if they’re too bright you replace the bulbs for lower rated ones until you get the light level right (or use a dimmer).

Thanks all.

Having considered everything said, I’ve ordered as following:

Fire rated 12V adjustable steel brushed chrome finish fittings – £3.99 at Screwfix
12W LED drivers – £3.25 UK sourced (forget who exactly, but I have the emails I need to check)
5W (5x1W) MR16 LEDs – £2.54 from China (probably not the best quality, and may get some import duty, but at that price I’ll take a chance)

So under £10 a light (I have 30 downstairs and haven’t counted upstairs yet), nicer looking fitting than we have now and upgrading to fire rated while doing the job.

So far only the fittings have arrived and they’re surprisingly nice quality.

Upstairs will be cheaper as I don’t need the fire rating.

One thing to be careful of is that some LEDs don’t play nicely in enclosed fittings – the heat needs to dissipate from the back of the bulb, it’s not projected out as IR like a halogen – and I seem to have managed to fry one this way. On the other hand if your Chinese LEDs explode it’s probably better that they are in an enclosed fitting!

Trust me, having stuck one of the existing halogens in the enclosed fitting they do not project the heat out.

The can with the LED was warm (just warm – ie not cold), while the halogen’s can was too hot to touch.

And that’ll be Chinese LEDs like Deal Extreme lights.

Dimming.
I believe that no house should be without dimmers in at least the main living spaces. Having the “big lights” on full whack all the time is not nice. Others may feel differently, but that’s just my view.

That’s why we have table and standing lamps that are dimmer. ‘Big lights’ only come on when we’ve lost something, or are just popping in and out.

they do not project the heat out

They do, it’s just that they’re so inefficient that the remaining heat is enough to heat the can! On the plus side halogens don’t mind the high temperature so much. The problem in my case was I think that there wasn’t enough thermal contact between the LED and the can to cool the LED by conduction, and no airflow to cool the thing by convection because of the can. But of course YMMV.

Your point is valid Rio, but I suspect not as big in reality as you might expect.

The cans have air holes at the top, and as adjustable ones, gaps at the bottom. It’s the intumescent material that closes the holes for fire barrier purposes.

As I said when I ran them in free air they never got more than lukewarm so even in the ceiling I doubt there would be a problem.

The halogens, given how hot they got, I’d be concerned about installing in the ceiling.

Ah, now my cans didn’t seem to have holes (hard to see as they’re embedded in the ceiling) so you’re right, you may not have the same problem.

Edit: I’d be interested to hear how you find it in terms of light levels when its all in.

The halogens, given how hot they got, I’d be concerned about installing in the ceiling.

Indeed – when I replaced my halogens with LEDs I found more than one melted transformer case and a scorched bit of wire. LEDS much safer in comparison.

Upstairs will be cheaper as I don’t need the fire rating.

How are you dealing with the insulation above?

If you want some further opinion then I would say this.

1. Go for a known brand like Philips, Osram etc if you can afford to or buy 1 cheapo Chinese lamp and try it. I have had good results with some of the cheaper 12v MR16 LED but less so with the 240v GU10s. I have had some cheapo ones go bang in a very spectacular way. Philips for me has always had the best light output, colour temperature and dimming curve. Which leads to..

2. Use a good quality dimmer designed for low load LED fittings, you will experience flicker and stepped dimming and worse otherwise.

3. Be careful of colour temperature, please don’t go for cool white unless you really need to provide bright light. It will make the room look sterile.

4. Don’t believe the wattage and light output figures, I have seen bright 4w lamps and dull 9w lamps. Also be aware of how inefficient the drivers can be.

Part of my job is to be a lighting designer/integrator doing things like this http://www.flickr.com/photos/technophobe/6877270287/in/set-72157629320303549

but in our shower the water flowing from the tap / shower head either looks like lumps coming out of the tap or that the water is moving upwards.

eh? Explain!

using GU10’s you’re not avoiding transformers, you’re just packing them into a very small space on each and every bulb

That’s what I’d read as well, but didn’t know enough to be sure it was the same for LEDs as for halogens.

Some LED replacement lamps have very little/no protection between the 240 side and the housing especially if it came from china. Fit carefully.

We have replaced 11 50w GU10 Bulbs with 3W eBay alternatives (warm white)

Although they draw around 6w each I am still happy with the result. They are bright enough at night. The photograph was taken about an hour ago in fading grey overcast daylight.

It’ll be interesting to see how long they last, but for £20 for 10 I’m not complaining as the ROI will happen over a very short period of time.