Replacing MR16 Downlights

I have been looking for a recent thread on this but couldn’t find one.

I have a 15 yr old single storey extension (crap build quality) with a high kitchen ceiling with no person access. The lights are the same age as the extension but there isn’t quite enough light any more, feels like they have become dimmer, not sure why, so looking at options.

There are 16 currently lights, in two banks of 8, but I might want a couple more. I have no idea where the transformer(s) are or what size they are. They run on 2 dimmer switches, so I assume there are 2 transformers, but I have no idea. The MK module slider switches hum, if that helps.

One option is to cut a hole in the ceiling to enable access and re-insulate it properly, but I am not as light / flexible as I need to be, so not my first option. Thinking of moving in about 5 years when child might move out.

Q. Should I just replace the bulbs with LED equivalents or try and fit 230v from underneath and hopefully come across the transformers ?

Are there better options ?

Is accessing the ceiling void inevitable ?

Advice appreciated !

Chances are there’s a transformer for each light and it will pull out when you remove each existing light.
I changed all our 12v halogens (about 40 of them) years ago and it’s a great thing to do.
If there’s a transformer on each light just remove it and replace with a 240v GU10 holder.
Easily done from underneath… Just isolate them first!
You’ll need new dimmers for LEDs though.

Thanks, though I suspect from the age of the installation that there won’t be.

I have had a poke around to check if there was any insulation and didn’t happen across a transformer.

Edit: should I invest in a Draper Wi-Fi Endoscope Inspection Camera ?

With a bit of luck each light unit has an individual transformer so you have mains to each unit – then its a simple job just pulling down the light unit removing the transformer and swapping it for a gu10 unit

If its two transformers in the ceiling void then its a much bigger job – one I had to do recently where you will have to find the transformers and replace them with junction boxes and run new mains 2+e to each light unit.  That will entail cutting access holes probably

If there is no access into the void my guess would be individual transformers but thats all it is – a guess.

If you pull one lamp unit out and there is no transformer visible a mirror and a torch can help see what is going on with any luck its a suspended ceiling with a nice big void and running new cables will be easy.  In my case ( I had done the original wiring!) the cables were run thru holes drilled in the joists.  that made it an utter pain

Our house had MR16s when we moved in. Each lamp had its own transformer, which was lying on the plasterboard in the void. I replaced them with GU10s by just removing the transformers and connecting the feeds to the GU10 fittings. More recently I was able to do a straight swap for LEDs. I suspect that your installation will be rather more complicated due to your dimmers, but it’s certainly worth removing a fitting and having a look in the void to see what’s what.

Wondering about getting a Wi-Fi Endoscope Inspection Camera to take out the guesswork ?

We changed about thirty downlights to led last year. sparky told to just rip all the old stuff out and had to drill new holes as the wife had insisted on stupid small lights bitd, and we got him to sort out switches which were annoying muddle. No need to access ceiling voids all done from below. IMHO this is the sort of job a decent tradesman will bang out regularly so can do it easily and quickly Money well spent should’ve done it ages ago

If you want mr16 leds I have a load of them from when I replaced with gu 10s.

We replaced most of ours with 240v LEDs. Why do you want a dimmer switch when it’s already too dim? You don’t.

We also found that not all 12V leds are equal. Our remaining bathroom lights were very dim with one brand, and when I replaced the bulbs with another brand we now need sunglasses! Could just be that the bulbs are not compatible with the transformer?

Could just be that the bulbs are not compatible with the transformer?

Or they could have been different wattage or colour – there’s many variations. Apparently LEDs do get dimmer as they get old although I’ve not really noticed in the 8-10 years I’ve been using them.

Edit: should I invest in a Draper Wi-Fi Endoscope Inspection Camera ?

I doubt it. Just pull one of the existing bulbs (and the cable) out of the hole in the ceiling. My money is on one transformer/light as thats probably the easiest way to fit them with no access from above.

Oh – and when I changed mine this was the state some of the MR16 cables were in – the lights were still working but were a bloody fire hazard!!

Wondering about getting a Wi-Fi Endoscope Inspection Camera to take out the guesswork ?

Whilst you can never have too many tools, we have one of those and it only gets used where there’s no way of getting a phone camera in; when I replaced the downlights in our kitchen I just removed one of the lights and poked a phone in the hole to see what was going on. It turned out the MR16s had separate transformers so it was just a case of taking out the fitting and the transformer and replacing them with dimmable IP6X fire rated fittings with the same diameter and a new LED dimmer switch. I used downlights with built in LEDS rather than GU10s – given the lifetime of LEDs the seperate bulb seems like a bit of an anachronism.

Why would you install GU10 LEDs these days?!

GU10 is a standard invented for halogen bulbs, they run hot. When using LED bulbs in GU10 fittings they get far too hot (LEDs cannot cope with heat, whereas halogen are designed to run hot) which causes premature failure. Far better to install LED fittings which will dissipate the heat properly

Edit – cross post with @Rio – what they said 🙂

Why would you install GU10 LEDs these days?!

Because if you fill a room with downlighters and one of them fails, the replacement probably won’t match the colour / pattern / brightness / fitting etc. You can at least bulk-buy GU10 LEDs for pennies.

I am not sure that is so tomnavman – halogens create much more heat than leds and that heat needs to be dissipated.  halogen can cope with more heat yes but if the excess heat is not dissipated then the halogen will burnout so the gu10 housings do dissipate the heat.  they are not insulated

I have just checked the high power led gu10s I have and they are barely warm having been on several hours.  certainly not hot enough damage the leds.  these leds gu10s have bee in place for 3 years and none have gone.  those are open back units tho not the closed back fireproof ones.  I also have some fireproof closed back ones and I will check them later once they have been on for a few hours.

the reason i went for gu10s rather than dedicated led units was so I can change them around if i want.  Different power or colours

When using LED bulbs in GU10 fittings they get far too hot (LEDs cannot cope with heat, whereas halogen are designed to run hot) which causes premature failure.

I don’t understand this… I’ve just had an 8w LED GU10 running for 20 mins and it was barely warm in my hand. I’ve still not lost any of my 40-odd GU10 LEDs in 8 years – let alone prematurely.

If you think about it – a 10w LED is about 70% efficient so produces about 3w of heat….. which is eff all!

edit: TJ beat me to it.

In best STW practice I seem to have sent this discussion off on a bit of a tangent, but possibly a useful one. From my reading around the building regs it seems that we should all be using fire-rated downlights, particularly in kitchens. So the old open-backed ones with effectively a bulb in a hole in the plasterboard are a legacy and not now recommended and you need to seal the hole at the back. If you want water ingress protection then you need to seal it from the front as well. As sharkbait points out LEDs rarely fail. Therefore if you’re replacing them then having the whole thing as a unit with a proper thermal design makes sense but isn’t compulsory if you still feel you may need to “change a light bulb”. If you want different powers then you can use a dimmer switch. And yes I know you don’t need to apply building regs retrospectively!

Thanks all, useful comments.

Will do more investigations at lunchtime

Part of my thought process was whether to re-insulate at the same time.

Rio – yes the ones in my bathroom will need to be replaced to get a fire cert!  really irritating but thems the regs especially as the “fireproof” ones still have vent holes in them.  You can also fit fire hoods over them if you really want

As an aside I just checked the temperature of the ones in fireproof housings.  Barely warm after being on for a couple of hours

MR16 dimmable LEDs

Like these

I replaced a dozen 14 year old 35W halogen lamps in our kitchen with those 2 years ago (they were less than half that price then!) – just plug them in to the existing fittings. We have one transformer per 3 lamps, and they worked fine with the LEDs. All are fed off a common dimmer switch. They gave very noticeably more light than the (aged) halogens that they replaced. If I was doing it again, I’d go for the ‘dim to warm’ option of the same thing. The only other point is that when they’re switched off, they look quite dark in the fitting, rather than the silver of the halogen reflector.

(The halogens lasted a good 12 years in daily use for extended periods before the first failure.)

With regard fire rating, technically you only need fire rated if there’s a habitable space above but it’s harder to find non fire rated than rated so there’s no point not doing it.
The fire part is usually the seal that fits between the bezel and ceiling, it’s made of an intumescent material which expands and fills the hole when it gets hot, so you can still have an open back to let heat from the lamp disperse

Why would you install GU10 LEDs these days?!

in my case, smart lighting. Our lounge has 8 hue GU10 leds, a hue lightstrip behind the tv, hue bulbs in the main lights and table lights. All controlled by a single remote (well a pair of single, one by the door, one by the coffee table, but they do the same thing) so its easy to switch between different light scenes. Or just ask alexa to watch a movie and the lights to go the right level, tv, sub, home cinema amp get turned on and put to the right channel and the heating in that room goes up a couple of degrees. Perfect.

With a bit of luck each light unit has an individual transformer so you have mains to each unit – then its a simple job just pulling down the light unit removing the transformer and swapping it for a gu10 unit

You were right !

Just need to work out replacement options and options for switches.