GU10 recessed downlighters

10-10-20 · 10-10-20

I'm interested in hearing comments on these downlighters that have been all the rage for a number of years and have in my mind a number of design issues that could cause me worry.

I bought a second hand house in windy Sandyford in late 2005 and I spent many a chilly night in it, even with the heating up full.
The house was built in 2003, and the owner/builder fancied himself as an architect. Enough said!

In my front playroom of approx 160 sq foot (currently used for storage) we had 10x 50w downlighters installed in the ceiling. The playroom was adjoined to the structure of the house, so had a roof-space above it with very poorly installed Kingspan 100mm insulation boards between the rafters.

We found that no matter what amount of heat we pumped into the room, we could not retain it due to the combined losses of the lack of insulation and the break in the thermal envelope caused by the downlighters. It also caused drafts throughout the house due to the exposed nature of the roof and the ventilation holes in the downlighters.

I spent a number of hours trying to rectify this, and my final solution was as follows:

1. I moved the Kingspan insulation from between the rafters and put it on top of the ceiling. This eliminated the need to heat the space between the ceiling and the roof and meant it was easier to completely insulate the horizontal ceiling as opposed to the 45 degree roof.
2. I left cut-outs in the insulation around the downlighters to provide ventilation.
3. I removed 4 of the 10 downlight fixtures and sealed the holes. The remaining 6 provide more than enough light for the room!

We then found that the room retained heat much better. The thermal-valve on the radiator now sits at 1.5 instead of 3.5!

My concerns on the use of these downlighters are as follows:
1. The light fixture requires ventilation sufficient to keep the encapsulated glass bulb cool enough to maintain the maximum lifetime. Hence, you can't block the vent holes on the top-most part of the unit to prevent drafts.
2. The design of the units require that the thermal envelope, if created on the ceiling, be broken, and also appear to cause a mini stack-effect (chimney) in the ceiling.
3. It's not possible to cover the lighting enclosure at the rear due to #1 and because the generated heat would be enough to become a fire hazard.
4. You can source fire covers for these downlighters, but they are not rigid or draft-proof.

It appears that if you want to maintain the thermal barrier in a ceiling, you need to get away from using lights of this type, but due to the fact that I have over 40 of these installed in various rooms throughout the house, I can't justify replacing all of them without a viable solution. If I move away from recessed downlighters, I'm left with 40+ holes in the roof!

Does anybody have any ideas or options? I'm considering LED based replacements, but the cost alone would appear be >€60 EACH at best!

Comments appreciated!

bro' · 15-03-2007 6:36pm

If i understand right you have placed 100mm kingspan between the joists instead of the Rafters...Normally it is mineral wool/rockwool insulation of a specified thickness installed between the joists so not sure what insulation properties your kingspan will give and if it would meet todays requirements. I'm sure there are other guys here who could comment better on that but you may find you could improve on your insulation to yield better heat retention.

With regards the downlighters there are several threads on here in relation to low energy downlights as with so many in your house the bills must be fairly high!
See the attached link for possible firecap covers in the attic which say they give a vapour seal and would eliminate draughts if sealed as instructed.
I found them as i was looking for some covers for my attic lights but they are not cheap at around 9GBP each :eek:

Ooops link is http://www.aico.co.uk/firecap_loftcap.htm

CJhaughey · 15-03-2007 8:33pm

GU10 leds are available but not at €60 ea!!
I would tell the supplier of these to take a running jump.
I got my LED GU10's from the UK www.ultraleds.com
the most expensive GU10 is £25 stg and and he will give you a deal if you buy more than 10.

10-10-20 · 16-03-2007 11:15am

bro' wrote:

If i understand right you have placed 100mm kingspan between the joists instead of the Rafters...Normally it is mineral wool/rockwool insulation of a specified thickness installed between the joists so not sure what insulation properties your kingspan will give and if it would meet todays requirements. I'm sure there are other guys here who could comment better on that but you may find you could improve on your insulation to yield better heat retention.

Well, I moved the kingspan from the rafters onto the joists. It had fallen away from the rafters as it wasn't installed correctly - it is a pain to do! Although it's 100mm, I placed another 100mm or so of rockwool ontop to bring the insulation thickness to ~200mm. I neglected to mention this.

With regards the downlighters there are several threads on here in relation to low energy downlights as with so many in your house the bills must be fairly high!

I've a policy of not replacing the bulbs until we really need them. Works a treat and keeps the energy usage low! I'll search for the threads.

See the attached link for possible firecap covers in the attic which say they give a vapour seal and would eliminate draughts if sealed as instructed.
I found them as i was looking for some covers for my attic lights but they are not cheap at around 9GBP each :eek:

Ooops link is http://www.aico.co.uk/firecap_loftcap.htm

I have purchased GU10 LED replacement bulbs - I got them for €13 each, but the temperature colour and lumens per watt is very low, so I'm looking more to replace the whole downligher fitting in the ceiling. This runs into big money depending on the solution.
I'll do some more searching and see what I uncover.

10-10-20 · 16-03-2007 11:29am

bro' wrote:

Ooops link is http://www.aico.co.uk/firecap_loftcap.htm

Brilliant - these are what I have been searching for.
Were you able to purchase directly from the company or how did you find out about pricing?

bro' · 16-03-2007 2:24pm

10-10-20 wrote:

Brilliant - these are what I have been searching for.
Were you able to purchase directly from the company or how did you find out about pricing?

Hi ,I just found this crowd from google ....http://www.allaboutelectrics.co.uk/index.php?doc=12&vid=2447

But I'm sure the manufacturing company could list other suppliers. i never pursued it based on cost but may again as it is a one off payment and I only have 15 downlights in my attic to consider?

10-10-20 · 16-03-2007 2:47pm

Good find. The ones you need for GU10 lamps appear to be these ones:
http://www.allaboutelectrics.co.uk/index.php?doc=12&vid=325

Cheaper again!

olearydc · 16-03-2007 8:09pm

These look the real things for the hot gu10's

Halolite GU10 Fire Rated Downlight Nickel 240V

But in case its a No no..
How about using Led's...a lot cheaper then you think (also last 10 times longer if not more!!)
I have started using 1 + 3 watt LEDS...1 watt is 6 euro and 3 watt is approx 10 euro

Im using 1 watt in the hallways, left on all the time (no heat)
3 watts in kitchen and bathroom (again no heat)

regards

10-10-20 · 18-03-2007 11:38am

olearydc wrote:

How about using Led's...a lot cheaper then you think (also last 10 times longer if not more!!)
I have started using 1 + 3 watt LEDS...1 watt is 6 euro and 3 watt is approx 10 euro

Im using 1 watt in the hallways, left on all the time (no heat)
3 watts in kitchen and bathroom (again no heat)

regards

Hi, I assume you referring to Cree or K2 LED's?
I bought a 3W (?) white K2 LED (just the plain LED) recently and was testing that for general use, but they are so difficult to mount and cool that I dropped that idea. Where are you geting 1W for €6? Are these mounted and finned?

I have installed various LED lights around the house so far - I have underpress LED lighting in the kitchen and a pull-out drawer with automatic lighting also. These were all based on superflux LED's which I made PCB's for. Yesterday, I was insulating the attic and my hand-lamp balast blew, so I ripped out the tube and replaced it with a PCB of 27 superfluxes and ar it off a 12v power supply! Works a treat!

Tell me more about your system?

olearydc · 18-03-2007 4:33pm

Hi 10-10-20

What happened was I built a extension with my father last year
and we made put in about 30 downlights...all Gu10's (great idea at the time!!)

If all the Gu10's were on..it would have been about 30 * 50 watts = 1500 watts near enough like having a kettle on all the time!!
But they have started blowing, so started looking for low wattage versions and had started replacing with 35 watts bulbs..

But noticed in Woody's (hardware shop in Cork) that they had LED versions
and bought 3 in a pack for 33Euro (all white and 1 watt each) to see how they faired out, and found them bright enough for the hallway.

Went online and did some checks and found these people in Dublin with prices a lot cheaper and with Free P+P for anything over 60 euro

3 Watt GU10 LED Lamps = Price: €9.75

1 Watt GU10 LED Lamps = Price:€5.99

I found the 3 watts LED's perfect for my office and have now ordered a number for the kicthen, in warm white as normally white seemed very sharp..

Try some of them out to check it also..might just be me

worked out if I replaced all 30 lights with 20*3 watts and 10*1 watt
AND left the lights on all the time, energy would have gone down from 1500
to 70 watts !!!..But only leave the 10*1 watts on in the hallway and bathrooms on mostly at night for the kids

From the web site ..

Energy Saving LEDs:

In general, today's LEDs (light emitting diodes) are more energy efficient than incandescent bulbs and halogen light sources.

A basic rule of thumb would be a 1 Watt LED Lamp gives out the equivalent of a 10 to 20 Watt Incandescent Lamp (Normal Household Bulb), depending on the reflective surface that the light is bouncing off.
Our 3 Watt GU10 LED Lamp - LL86 would give out approximately the same about of light as a 30 Watt Incandescent Lamp, yet is much more energy efficient (saving on electricity bills), lasts longer and gives off very little heat.

LED Candle Lamps –LL79, LL80 & LL84 give out approximately the same amount of light as a 10 Watt Incandescent Lamp. LED Golf Ball Lamps - LL81 & LL82 give out approximately the same amount of light as a 15 Watt Incandescent Lamp.

A LED Lamp that gives off 0.2 Watts of light for example our LED Recessed Garden Decking Lights -LL31 & LL33 uses approximately:
• 500 times less energy than a 100 watt incandescent bulb.
• 300 times less energy than a 60 watt incandescent bulb.
• 200 times less energy than a 40 watt incandescent bulb.

any questions let me know..

EDIT

Also there is NO heat from these LEDS, when left on all the time, can touch them with fingers or change them,
I dont feel any heat...so a lot safer then the 50 watt GU10's in a house
also they are not as bright as the normal bulbs, but good enough for me with a wider coverage

barry75 · 18-03-2007 5:13pm

Hi Olearydc,i am about to put 30 odd recessed lights into my new build but want to be able to dim the lights in living room etc.Can LED's work on a dimmer switch?

olearydc · 18-03-2007 7:05pm

barry75 wrote:

Hi Olearydc,i am about to put 30 odd recessed lights into my new build but want to be able to dim the lights in living room etc.Can LED's work on a dimmer switch?

Hi barry75

I remember reading somewhere that LED's dont work with dimmer switches..
But will double check and post any link or information when I find it...

ircoha · 18-03-2007 8:34pm

olearydc wrote:

Hi barry75

I remember reading somewhere that LED's dont work with dimmer switches..
But will double check and post any link or information when I find it...

AFAIK u cant dim the cfcs as they are really mini flouresents

I have 2 leds with 2 gu10s on a dimmer and the leds dont in fact dim. they are on or off.
one prob with the cfcs is they take a while to warm up and reach full output so dont put them in the head unless u can ready aim wee in the (semi) dark:)

antoinolachtnai · 19-03-2007 2:47pm

I think there are LEDs out there somewhere which will dim. They have to have special circuitry in them.

10-10-20 · 20-03-2007 3:03pm

You need a different type of dimmer for most LED systems. Most dimmers are modulating and don't work.

10-10-20 · 20-03-2007 3:11pm

olearydc wrote:

Went online and did some checks and found these people in Dublin with prices a lot cheaper and with Free P+P for anything over 60 euro

3 Watt GU10 LED Lamps = Price: €9.75

1 Watt GU10 LED Lamps = Price:€5.99

I found the 3 watts LED's perfect for my office and have now ordered a number for the kicthen, in warm white as normally white seemed very sharp..

Thanks for the links. There is a new LED type which is a little more expensive but produces better lighting (called K2 or Cree) and these will start to supersede the lamps like what you have linked to above. These are interesting all the same - my previous purchase of similar bulbs was soured by the fact the the 'warm-white' bulbs were blue in colour, and nowhere near a true incandescent light colour temperature of 3500k.
http://www.3drender.com/glossary/colortemp.htm

Stoner · 21-03-2007 11:35am

There is a 7 Watt and Watt CFL lamp that works in GU10 lamp holders. A 9W one will give you about 65 of the light of a 50Watt GU10 Halogen lamp, they last up to 15000 hours. The cheapest way to get them at the moment is in a complete light set, they are Megaman units and are available from Kellihers electrical about 20 euro each, they may also have replacement lamps for cheaper if you are lucky
http://www.kellihers.com/

LED lamps are not good quality lights, they will not replace a GU10 fitting,
the is an irish distributer of LED lamps, they do the 18 and 30 lamp units, at the mopemnt I would recomment LEDS for decoration and minimal light only,
Also you have to pay morte for an LED lamp that is "White" and not the cold blue light that most "white" LEDS are.

http://www.loweleds.com

these guys are good.

Regardsing dimming, you can't dim the 7W or 9W CFL fittings.

Dimming LEDS is possible but a little difficult at the moment, however IMO they are so dim anyway you'd not want them any duller.

As a LED lamp it about 1 to 2 Watt there is a problem with dimmers as most domestic dimmers cover a range atarting at about 20 W to 250W or 20W to 500W , 20W to 750W etc, the wattage of these almps is usually to low to register on these dimmers. Sounless you have about 50 LED lamps on a domestic dimmer you wont get much of a budge on them dimmingwise.

The solution to this is LED driver units, these will dim the lamps but are too pricey for a domestic application and as i said they are dim enough as it is.
Finailly I forgot to mention the the CFL lamps dont get anywaher near as hot as a GU10, GU10 lamps are stupidly hot and I'd run a mile from them, generally they are installed as they save about 8 euro on a traffo and save two connection points for the sparks.

So my advice is get a couple of LED lamps from the guys above and get a couple of CFLs , try them out I'm fairly sure that you will go with the CFLs the only issue with them is the lamp warm up time and not being capable of dimming

regards

Stoner

billy_beckham · 21-03-2007 12:03pm

Just on the CFL's for the GU10 lights, they are a lot longer than the normal bulb and will not fit in all fittings...just something to think about:D

Stoner · 21-03-2007 1:00pm

billy_beckham wrote:

Just on the CFL's for the GU10 lights, they are a lot longer than the normal bulb and will not fit in all fittings...just something to think about:D

that's a very good point, I was talking about standard LV downlight application fittings where height above the fitting is an issue, this extra height on the CFL can also stop eyeball/adjustable fittings from completing their angle of adjustment.

Mr Digger · 10-07-2007 12:23am

try www.futureleds.com :-)

McSandwich · 10-07-2007 12:37am

I found this site quite good for cfl and led gu10s:

http://www.gbbulbs.co.uk/acatalog/GU10_Energy_Saving.html

Cuauhtemoc · 10-07-2007 11:42pm

I can't find any leds on that gbbulbs site.

This may be a stupid question also

I have a 30 watt energy saving bulb which is 150watt equivalent. Can i use it in a lamp that says max 100watt bulb?
Same goes for 60 watt energy saving(330watt equivalent).

Cheers.

C.

Stoner · 11-07-2007 8:15am

Cuauhtemoc wrote:

I can't find any leds on that gbbulbs site.

This may be a stupid question also

I have a 30 watt energy saving bulb which is 150watt equivalent. Can i use it in a lamp that says max 100watt bulb?
Same goes for 60 watt energy saving(330watt equivalent).

Cheers.

C.

There are LEDS here
http://www.loweleds.com (these guys are based in dublin)

That's not a stupid question, and yes it's no problem using the energy saving bulbs in the 100W fittings.

Just don't try to use them with a dimmer, straight forward switching only. (they dont operate very well on security type fittings either as many take a long time to heat up, but people still use them.

CJhaughey · 11-07-2007 9:14pm

I have seen a new fitting from megaman recently, a cold cathode which is dimmable without a dimmer!
It works by switching the switch on and off.
eg pressed once= 100% light, pressed twice = 66%
pressed three times =33%
four times= off.
brilliant idea.

Stoner · 12-07-2007 9:13am

that's a great idea alright, do they work on a dimmer too?

10-10-20 · 12-07-2007 11:26am

No, by the sounds of it, it has logic in the controller and is not externally dimmable.

Stoner · 12-07-2007 2:38pm

Megaman DS dimming

D=Dial
S=Switch

Had a look and it will dim on an on/off switch and a dimmer

http://www.megamanuk.com/pdfs/2007-catalogue/dors.pdf

Great idea, going to get some and give em a bash.

Looks like a special dimmer switch though, as it is a Dial, but really an on/off switch

Edit:

OK so it has a number of different light levels, and you can use a standard dimmer with it , but you go from max to min on the dimmer to get it to work, so it just reacts to max and min voltage,
so it will work on a standard rotary dimmer and standard switch