Dimmable LED lights: GU10s or shallow panel?

[ashirusnw]

We've completely refurbished and rewired our house, and allowed for 8-9 spots/downlighters in a six 4.7m x 3.2m bedrooms (2.45m high) and in hallways and bathrooms. The ceilings have about 25cm between plaster and floorboard including fairly high grade rockwool.

The wiring is already done (9 lights on one switch) and the ceiling plastered so if it's a mistake to have so many, it's too late.

My query:
If I use GU10 fire rated fittings, good quality bulbs, and get a compatible dimmer might heat dissipation be a problem and cause bulbs to be short-lived?

Are there any advantages to a low profile (shallow panel) integrated fittings (like this) over GU10 fittings, especially if they must be dimmable? The low profile means we can space them more evenly and not worry about pipes or joists.

More info

I have excluded using tall integrated fittings because these are quite powerful and 8-9 of them would be too bright in one room as many tall (as apposed to low-profile) fittings are 750 lumens plus.

I haven't considered MR16s with fire hood transformers (i.e. GU5.3s with SMPS - for the very pedantic!) about £12.50/fitting as I can't see an advantage over GU10s.

I am aware that some people hate spotlights in bedrooms, and 2" bulbs even more. I'm fine with them - especially when they're dimmable and even if I wasn't it's too late to change.

 

[ericmark]

Size matters, a light 800 lumen 2 inches across gives out less light than one 3 inches across, in the main the non MR16 (be that GU10 or G5.3) cover a larger area than 2 inches, and the LED replacement for MR16 covers less than 2 inches, so small panel lights are normally better.

 

[ianniann]

Just for the record, halogen MR16s are better in almost every way than halogen GU10s. However, with retrofit LED lamps the opposite could be said to be true. The lamps themselves are now essentially the same, but operation directly from a 240V supply that doesn't care much about the load is far more reliable than designing a lamp for an unknown 12V supply that wasn't designed to power an LED driver. In particular, dimmable "MR16" LED lamps are far more likely not to dim properly on a legacy transformer.

If you are starting from scratch, you might want to avoid the whole minefield of compatible dimmers and retro-fit lamps. Go directly to a digital dimmer such as a DALI LED driver. Then you'll get reliable smooth dimming down to lower brightness than a retrofit lamp could manage. Ironically you will then be looking at the LED equivalent of MR16 lamps again, 12V (possibly 24V) with a DALI-compatible driver. Also available with panels, in fact this sort of system is much easier to find for commercial applications with larger light panels.

 

[winston1]

Just for the record, halogen MR16s are better in almost every way than halogen GU10s.

And just for the record you are writing rubbish.

Many halogen MR 16s are GU10s.

MR16 is the size of the multifaceted reflector in eights of an inch.
GU10 is a type of base.

 

[ban-all-sheds]

Many halogen MR 16s are GU10s.

And many GU10s are MR16s.

 

[ban-all-sheds]

I haven't considered MR16s with fire hood transformers (i.e. GU5.3s with SMPS - for the very pedantic!) about £12.50/fitting as I can't see an advantage over GU10s.

G5.3 lamps are easier to get in and out than GU10s as you don't have to twist them, which can be hard to do if they've been in for a while.

I am aware that some people hate spotlights in bedrooms, and 2" bulbs even more. I'm fine with them - especially when they're dimmable and even if I wasn't it's too late to change.

Keep telling yourself that.

With any luck you won't realise what a stupid lighting design you have until it causes you problems selling the house.

And if it's too late to change why are you asking about panel lights? You're stuck with using recessed 2" torches now.

 

[ianniann]

Another thread sent down the pan ...

 

[ashirusnw]

Another thread sent down the pan ...

Indeed. I had tried to get this information about gu10s by reading previous threads but unfortunately the discussion was derailed by these two bickering. Winston1 in particular really ruined the OPs question in other threads in a similar fashion.

If you're willing to help me and others, please ignore the sidetracking and please re-read my question (in which I preempted ban-all-sheds objection to spots and winston1's non-contributory pendantery, but to no avail).

Back to the original question: is having high grade insulation above a GU10 fitting a big issue?

And what's the absolute best way to yet nice even dimming from a gu10?

The reason why I didn't want to get panel lights originally is that:
1. I prefer to change GU10s every 1-2 years than an integrated fitting every 10 years as the with the latter, I tend to damage the plasterboard as you have to pull the whole thing out (and won't be done by my wife or kids).
2. And in the case of integrated LED fittings or panel fittings, when they eventually do blow - and of you have 50+ of them some will fail every so often - you have to find a matching fitting of the same dimension and look many times in the next 5-20 years. Compare with just changing a lightbulb like we've all been doing for years.
3. I also personally prefer lots of little fittings in bedrooms to large panels which, to me, look like a retail showroom.
4. So I'm reasonably happy with spots in bedrooms and they have the become the norm in many new builds. Have enough of them and they light up all the room. Have them on a dimmer and it's not too bright at bedtime. Have them on the full brightness when the kids are playing with their toys or doing homework at their desk. I don't see the problem. (Not to mention that many people use them in tandem with led strips or adjustable fittings to create a nice ambient light.)
5. Finally, I've had years of changing Halogen Gu5.3 transformers/drivers/SMPS/whatever-you-care-to-call-them and when you have over 50 of them they tend to blow one or two a year which is a much more massive pain then changing a GU10 bulb -- and all panel lights that I've seen need a separate driver (although I think these now tend to be click-in connectors rather than having to use a screwdriver up a ladder to change it) -- so there's another component that's not dead simple to change and could fail.

Thanks for any constructive help,
Ash

 

[ban-all-sheds]

Back to the original question: is having high grade insulation above a GU10 fitting a big issue?

Ash - is is not pedantic to answer that by saying "it depends entirely on what type of lamp with a GU10 base you are using". Or alternatively "the base is of no relevance, so focusing on it is not going to be of value".

And what's the absolute best way to yet nice even dimming from a gu10?

Ditto.

The reason why I didn't want to get panel lights originally is that:
1. I prefer to change GU10s every 1-2 years than an integrated fitting every 10 years as the latter tends to damage the plasterboard as you have to pull the whole thing out (and won't be done by my wife or kids).

Then don't recess them into the plasterboard. That, BTW, is a practical suggestion to counter your objection.

2. And in the case of integrated LED fittings or panel fittings, when they eventually do blow - and of you have 50+ of them some will fail every so often - you have to find a matching fitting of the same dimension and look. Compare with just changing a lightbulb like we've all been doing for years.

Then don't have such a ridiculous number of them. That, BTW, is a practical suggestion to counter your objection.

4. So I'm reasonably happy with spots in bedrooms and they have the become the norm in many new builds.

So has, it seems, institutional and systemic contravention of the Building Regulations. That, BTW, is a truthful observation which shows that one should not necessarily be guided by what has become the norm in many new builds.

Have enough of them and they light up all the room.

Then don't have the type where "enough of them" translates to "so many that normal life failures become a problem". That, BTW, is a practical suggestion.

5. Finally, I've had years of changing Halogen Gu5.3 transformers/drivers/SMPS/whatever-you-care-to-call-them and when you have over 50 of them they tend to blow one or two a year which is a much more massive pain then changing a GU10 bulb

Then don't have such a ridiculous number of them. That, BTW, is a practical suggestion to counter your objection.

 

[flameport]

Back to the original question: is having high grade insulation above a GU10 fitting a big issue?

Yes, because even with LEDs, it will cause them to overheat and probably fail.
There are a few which the manufacturer states can be covered with insulation, but the majority cannot.

And what's the absolute best way to yet nice even dimming from a gu10?

Mains voltage lamps which are specifically designed for dimming, obtained from a known manufacturer. Many will work perfectly well with standard dimmers.
Low power LED specific dimmers can be obtained for the few situations where a standard dimmer does not work properly.

These are decent: http://www.toolstation.com/shop/p65928 , the 5W ones are far brighter than the equivalent 50W halogen.
If you don't want to spend that much per lamp, then these ones: http://www.toolstation.com/shop/p79758 are also perfectly good, and they also work with standard dimmers, including with only a single lamp being dimmed.

A sure way to failure is to buy lamps from ebay and similar online tat emporiums.

 

[winston1]

Indeed. I had tried to get this information about gu10s by reading previous threads but unfortunately the discussion was derailed by these two bickering. Winston1 in particular really ruined the OPs question in other threads in a similar fashion.

If you're willing to help me and others, please ignore the sidetracking and please re-read my question (in which I preempted ban-all-sheds objection to spots and winston1's non-contributory pendantery, but to no avail).

When a member posts rubbish regarding a base, GU10, and a lamp size, MR16, it is not pedantic or non-contributory to want to know what they actually mean.

 

[ban-all-sheds]

Yes, because even with LEDs, it will cause them to overheat and probably fail.

Ash - FYI - LEDs do indeed produce very little heat, but they are extremely intolerant of even a very little. Bing for 'led negative temperature coefficient' and 'led thermal runaway'.

The problem becomes particularly arduous to deal with when a large number of LEDs (or a few powerful ones) are crammed into a small package, such as an MR16.

 

[ashirusnw]

And if it's too late to change why are you asking about panel lights?

It's difficult to change the number of fittings, not the type. They've wired it up for 9 fittings at certain positions. They're about to cut the holes for the fittings. I can skip some of the lights and do (say) 6 per room and use panel lights or integrated fittings if need be but it might to too late to change their positions to suit the new number of fittings.

it depends entirely on what type of lamp with a GU10 base you are using

What I'm after is a dimmable flush lighting that's

1. not too large (don't like large panels)
2. costs around £95 per 15 sq m bedroom (including suitable bulbs)
3. Recessed or flush (don't want hanging fittings)
4. realiably and smoothly dimmable down to low light
5. either replaceable bulbs (but not on a hanging/track fitting) or has click-in connectors and is simple to replace when it does fail

Originally I thought the typical GU10+MR16 bulb would suit, but as they're typically low lumens I specified 9 per bedroom (and should cost about £95 per room). But since I've heard about the heat issue with insulated ceiling, and found many reports of GU10+MR16 bulbs not dimming well, I'm nervous.

And what's the absolute best way to yet nice even dimming from a gu10?

Ditto.

I don't really care what type of bulb as long as it meets the requirements 1-5 above.

 

[ashirusnw]

Back to the original question: is having high grade insulation above a GU10 fitting a big issue?

Yes, because even with LEDs, it will cause them to overheat and probably fail.
There are a few which the manufacturer states can be covered with insulation, but the majority cannot.

How do these work? Do they radiate heat out the front? (Like PAR16s might do?)

Any links to dimmable products that can work?

Also will the fire hood help keep in the insulation from being a problem assuming I use good quality bulbs?

 

[ashirusnw]

Mains voltage lamps which are specifically designed for dimming, obtained from a known manufacturer. Many will work perfectly well with standard dimmers.

Ok, good to hear and interested to hear any contrary views. I heard to many issues like the bulbs not dimming smoothly at low brightness, or buzzing dimmers or variety of other issues.