Which Led's

[Jupiter01]

Hi Guys,

Can someone please get me started on selecting the LED downlights foor my property. I have a room which is 9m x 4.7m and I want downlights across all 4 sides. How do I detrmine how many lights I need and also the wattage and type of lights? The prices seem to vary between £7 and £40 a light but without any discernible differences.

I will have rockwool sound insulation packed between the joists so it needs to be "friendly" with this.

Look forward to your advice.

 

[dsharp7th]

i went for these for my latest room upgrade: https://www.downlights.co.uk/click-inceptor-micro.html

ticked a lot of boxes, cheap at £15, dimmable, tiltable, fire rated, easy install, no separate transformer and with an accessory to safely accommodate insulation above. to get all these features from jcc or aurora seems to be £40+, and i'm not sure what more you get for this. very happy with them, particularly knowing they're guaranteed for 7 years, but they lack the depth and aesthetic of some i brought previously for another room (no longer available) that had all of the above but the light was set in the concave silver dome like old halogen spots which gives an overall more pleasant aesthetic - look for 'COB downlights' in the product name to see what i mean.

i used 8 for a 3.5x4.5m room and 13 in a 7x6m l shape room and will generally use them slightly dimmed. i like to put them in 1000mm wide pairs, 600mm from the walls, aligned to features like windows and the chimney breast which seems to work well, especially for aiming at pictures, but you are slightly limited by joist positioning.

if you're going for dimmed, the varilight v-pro in all its forms is the wall switch you need.

 

[ericmark]

9m x 4.7m = 42.3m² the lux required for Kitchen ambient = 108 so you need around 4568.4 lumen so with a 5W spot giving around 350 lumen that means 13 spots lamps. or one 5 foot fluorescent tube or a pair of 5 foot LED tubes. That's the theroy.

Looking at my house with fluorescent tubes yes that is about right. However looking at my sons house with 2" spot lights it simply does not work and I needed to use a touch to read his central heating boiler. So in real terms spot lights must be arranged so as to give a spread of light which means shining off a white surface not aimed at the floor.

Having the LED's spread around is important, be it inside a tube as with the fluorescent replacement or in a tape around the edge but grouping the LED's into 13 spots will not really give the spread required. And using 38 x 2W at 120 lumen each will take and age to fit. Fitting two square or round surface mount lamps of 24W / 2000 lumen at 310 mm across will give a better back ground light than 13 x 50mm it is simple maths having 1992200²mm with light better than 25525²mm as it has 7.5 times the area to emit the light from.

 

[Iggifer]

so with a 5W spot giving around 350 lumen that means 13 spots lamps

Your lumen data is a little out of date. Enlite do a 5w that is 520 lumen. Gives them a better lumen/Watt than most fluorescent tubes.

 

[Jupiter01]

Thanks for tthe replies guys. Since I am placing these within rockwool insulation, I assume that I need to buy insultaion covered downlights? I can see that Aurora do some. Also, I do like the idea of adjustable head too and since I am around 650mm away from the side wall on both ends and the total width of the room is 4.7m, I may need to swing the head inwards. i can't be any further in than this as I have a metal beam on one side.

Look forwrad to the responses

 

[ban-all-sheds]

Does not the fact (confirmed by dsharp) that you need loads of lights to light up a room tell you that the lights aren't actually any good at lighting up rooms?

By all means have recessed lights, but use large ones - don't try and provide general room illumination by using an array of recessed torches. Not only will it not work well it will make your house look like a shop.

 

[ericmark]

so with a 5W spot giving around 350 lumen that means 13 spots lamps

Your lumen data is a little out of date. Enlite do a 5w that is 520 lumen. Gives them a better lumen/Watt than most fluorescent tubes.

As said before the specials can give 100 lumen per watt, there are one or two at 120 lumen per watt. However the standard unit picked up in the supermarket are between 60 and 80 lumen per watt and it seems the bigger the lamp the better with dimmer type not as good as non dimming. As said the types with PWM drivers built in for caravans DC 10 ~ 36 volt are nearly always 100 lumen per watt. It does seem they aim at a market, with a caravan the LED is replacing fluorescent so unless better than fluorescent not much point in making them, but with domestic they replace tungsten and any old rubbish is better than tungsten until you go to the larger units which again are replacing fluorescent so have to be good.

Some of the stick on strips are very good at 100 lumen per watt and some are simply rubbish at less than 40 lumen per watt some don't even say how many lumen per watt. So one has to be careful.

 

[ericmark]

Does not the fact (confirmed by dsharp) that you need loads of lights to light up a room tell you that the lights aren't actually any good at lighting up rooms?

By all means have recessed lights, but use large ones - don't try and provide general room illumination by using an array of recessed torches. Not only will it not work well it will make your house look like a shop.

In many cases I have to agree the small 2 inch lamps seem useless, however it is not the lamp it's how it's used. In my bedroom I have two GU10's either side of the bed to read with. As an experiment I turned these to shine on the ceiling and they lit the room well, in other words they were being used as uplighters. The white ceiling gave a good spread of light. However shining on the blue wall they are useless. Even with a basic bulb facing down cap uppermost they do not light as well as with the cap on the bottom shining off the ceiling. So nothing wrong with 2 inch spots it's down to the way they are used.

 

[JohnW2]

...So nothing wrong with 2 inch spots it's down to the way they are used.

Indeed - and also, crucially, what beam angle they have. Long gone are the days when all the bulbs/lamps used in small downlighters were 'spotlights'.

Kind Regards, John

 

[JohnW2]

... these are narrow-beam angle 2" lamps/bulbs being used (as intended) as spotlights ...

Kind Regards, John

 

[ericmark]

Yes I also used GU10 LED's as spot lamps for reading in bed. However nothing to stop one aiming them at a white wall and using for general lighting, only when aimed at a dark surface like a floor is there a problem.

 

[JohnW2]

Yes I also used GU10 LED's as spot lamps for reading in bed. However nothing to stop one aiming them at a white wall and using for general lighting, only when aimed at a dark surface like a floor is there a problem.

Sure - but if you are using them to illuminate a light wall (to produce 'general lighting), or even if you just have them pointing down from the ceiling, you should use wide-angle lamps/bulbs (not 'spots'), and you should not use fittings such as I illustrate above which are deliberately designed to further restrict the beam angle.

Kind Regards, John

 

[ericmark]

The LED lamp although a replacement for MR16 is not in the main a MR16 as it does not have a multifaceted reflector but instead either uses the limitation of the LED chip used or a lens to form a spot of light. The Osram unit I bought stated 25~35° and was clearly centre weighted with some type of lens and a single chip, the TCP unit stated 30° and had 9 LED's with no lens. The Livarno spot does not give an angle although that had a E14 base not the GU10 however still 16/8" so the tungsten version would have been a MR16.

Using diffusers can help spread the light and I have seen many MR16 compatible lamps where the area of illumination is much less than 2 inches part of it being taken up with cooling fins. I would say from 1 to 3 watt the light output is not that high anyway 250 lumen if your lucky so you need quite a high number of fitting, my kitchen is split in two and the laundry area uses a 2400 lumen tube so using 3 watt GU10 units would require 10 lamps just counting the lumen without considering using any diffuser to spread the light. One can only guess but likely there would be very little difference in the ability to see what you were doing using either method.

Where the problem arises is instead of using 10 @ 3W some one tried to use 3 @ 10W and the light is simply not distributed around the room. So we walk into a room like my sons kitchen with I think 4 @ 7W and I need a torch to read the display on the central heating boiler but had he used 9 @ 3W very likely the light would have been ample output the same but surface area doubled. However if I was fitting a lamp I think using two large 2D style fittings or 10 x GU10 type fittings I would be lazy and go for two large fittings rather than ten small. I have not as yet seen a real kitchen with LED tape. Look at the GU10 in the show room and they look great but in a real kitchen the 50W tungsten 2" fittings are a failure. The LED tape also looks good in the show room but how it works in real life is as yet unseen by myself. I would think it would work well, but why is the 24W replacement LED tube made of a diffusing material? Does it need that diffuser to work or is it just to look nice.

I have often wondered why were pearl light bulbs banned, to my mind they worked better than clear unless fitted inside a diffuser so why ban them?

 

[JohnW2]

The Osram unit I bought stated 25~35° and was clearly centre weighted with some type of lens and a single chip, the TCP unit stated 30° and had 9 LED's with no lens.

I would definitely regard beam angles that small as 'spotlights', and hence not suitable for general room illumination. Trying to illuminate a room with a 30° source is, as BAS often says, much like trying to do so with a torch! GU10 LEDs with beam angles of 60°, 90° and even 120° are all fairly readily available.

I have often wondered why were pearl light bulbs banned, to my mind they worked better than clear unless fitted inside a diffuser so why ban them?

It was obviously incandescent bulbs they wanted to ban, and since pearl ones were by far the most popular, by banning them they destroyed most of the incandescent market. Why they didn't initially ban clear ones as well, I'm not sure - but perhaps they felt that there were some specialist applications which currently require clear incandescent bulbs?

Kind Regards, John

 

[ban-all-sheds]

It was obviously incandescent bulbs they wanted to ban

Unlikely, given that they did not ban them.

Incandescent lamps are still freely available, allowed to be made in and imported into the EU, etc.

Given that what they did had no rational basis, I can only assume that what they wanted was to be irrational.