Planning ceiling lights

Olivias Grumpy · 3 Jun 2019

hi
Are there any guides for arranging positions of recessed ceiling lights.
My living room ceiling is approx 4.5 x 3.5m x 2.4m high

I’m thinking of putting in 2 rows of 4. But I’m not sure if there any required max/min dimensions between the fittings or side walls

Cheers

winston1 · 3 Jun 2019

Some on here would say don't put them in at all. Eight lamps in a room that would traditionally have one seems excessive.

But 1/3 and 2/3 of the width from one side for the rows makes sense. Then equally spaced the other way. But you may have to adjust them to avoid joists.

JohnW2 · 3 Jun 2019

winston1 said:
But 1/3 and 2/3 of the width from one side for the rows makes sense.

That only 'makes sense' if you want a lot more light down a strip in the middle of the room than at the sides (due to the 'overlap' of light beams between the two rows). If you wanted more even light distribution, then 1/4 and 3/4 would make more sense.

Kind Regards, John

donrkebab · 3 Jun 2019

Ignore these two above they're guessing, the standard arrangement is equidistant between lights and 1/2 that at end of run.

So for four lights - 1/8, 1/4, 1/4, 1/4, 1/8. and for 2 lights - 1/4, 1/2, 1/4,

JohnW2 · 3 Jun 2019

donrkebab said:
Ignore these two above they're guessing, the standard arrangement is equidistant between lights and 1/2 that at end of run. .... So for four lights - 1/8, 1/4, 1/4, 1/4, 1/8. and for 2 lights - 1/4, 1/2, 1/4,

"The above two" were talking (not guessing) about the side-to-side - your "1/4, 1/2, 1/4", which is what I described as 1/4 & 3/4 (measured from one side). However, winston was wrong (for uniform light distribution), for the reason I gave.

donrkebab · 3 Jun 2019

JohnW2 said:
"The above two" were talking (not guessing) about the side-to-side - your "1/4, 1/2, 1/4", which is what I described as 1/4 & 3/4 (measured from one side). However, winston was wrong (for uniform light distribution), for the reason I gave.

So now you add some more words to correct your unclear information, and I would love to watch you struggling with your tape measure. So what would you do if there were 4 lights?

JohnW2 · 3 Jun 2019

donrkebab said:
So now you add some more words to correct your unclear information...

Opinions may vary, but I personally regard as "1/4 & 3/4" as clearer than "1/4, 1/2, 1/4" - since the former are measurements from the same point, whereas the latter are the measurements between things.

Either method of expressing it is equally valid, provided that one explains what the figures mean. Even though winston's figures were wrong (for even light distribution) he did at least indicate that his 1/3 and 2/3 figures were "from one side",

donrkebab · 3 Jun 2019

JohnW2 said:
Opinions may vary, but I personally regard as "1/4 & 3/4" as clearer than "1/4, 1/2, 1/4" - since the former are measurements from the same point, whereas the latter are the measurements between things.

hahahaha, as I said before I would love to see you trying to use your method.

JohnW2 said:
Either method of expressing it is equally valid, provided that one explains what the figures mean. Even though winston's figures were wrong (for even light distribution) he did at least indicate that his 1/3 and 2/3 figures were "from one side",

The difference is, I know what I'm talking about and you are guessing.

oldbutnotdead · 3 Jun 2019

You may find 2400 is a bit low for downlights in a living room- lots of scope for glare in your eyeline while you're watching the telly, having to move the comfy chair so you get enough light from above and behind to read a book.....your call of course but before you start hacking the ceiling to pieces I'd suggest mocking the job up with some battens screwed to the ceiling with GU10 lampholders screwed/spiked to them and see how you like the effect

John D v2.0 · 3 Jun 2019

some people really get pleasure out of helping other people, unfortunately others get more excited by following the trump model of throwing around rudeness and insults. Perhaps it's liberating to not care what people think of you, to be the angry person behind the keyboard.

To the OP, regarding whether spotlights are alright, I had some success with this kind of thing as they produce a much wider beam angle so you benefit from more reflection: https://www.toolstation.com/led-slim-round-panel-light/p60675
Still not as good as a bulb below ceiling height, but better than spots.

winston1 · 3 Jun 2019

John D v2.0 said:
To the OP, regarding whether spotlights are alright, I had some success with this kind of thing as they produce a much wider beam angle so you benefit from more reflection: https://www.toolstation.com/led-slim-round-panel-light/p60675
Still not as good as a bulb below ceiling height, but better than spots.

Interesting. And at 780 lumens you would not want eight of them. I guess four would be enough but then there is the arrangement problem again.

Couple of snags, well three in fact.

1. Cool white is not really suitable for a lounge, but perhaps warm white is available.
2. Non LED replaceable, so when one fails you have to replace the whole thing which may no longer be available.
3. Non dimmable so if you do overdo it you can't turn them down.

John D v2.0 · 3 Jun 2019

Oh yeah we got 4000k ones and dimmable, and only two for an ensuite, but i agree it would need some thought. Lighting design is actually a very complex area to get completely right

Olivias Grumpy · 3 Jun 2019

Thanks to all for replies
I think I was on similar lines although I had read somewhere that they should be about 750mm from sidewall and approx 1/2 ceiling height to next one.
Therefore I couldn’t equate that idea into the width of room.

Anyway it makes more sense now
Already marked joist centres on ceiling and will tweak as required.

Next question is how to referee a Forum ?

JohnW2 · 4 Jun 2019

Olivias Grumpy said:
I think I was on similar lines ...

There is no 'one size fits all' answer. The 'traditional rule-of-thumb' figures you've seen mentioned here (with arguments about how they should be expressed) simply aim to distribute the actual lights evenly across the width and length of the room, but that is not necessarily the ideal (lighting wise) in a given room.

Olivias Grumpy said:
... although I had read somewhere that they should be about 750mm from sidewall and approx 1/2 ceiling height to next one. Therefore I couldn’t equate that idea into the width of room.

A more sophisticated approach than relying on the 'traditional rule-of-thumb' will, indeed, relate the spacing of lights to the room height, but that calculation/estimation has to take the beam angle of the lights into account (hence not "half of ceiling height" for all beam angles) - and, as you imply, can get silly for some room sizes (although, to be fair, if it does 'get silly' that probably implies that one has chosen the wrong beam angle for the room size). The optimum distance of end ones from sidewalls will depend upon factors such as the nature, colour and surface finish of the wall - as well, of course, as what light distribution one wants to achieve (not necessarily 'even' throughout a room).

Olivias Grumpy said:
Next question is how to referee a Forum ?

Now there's a question - answers to which will undoubtedly vary a lot

Kind Regards, John

donrkebab · 4 Jun 2019

Olivias Grumpy said:
Next question is how to referee a Forum ?

Hire a gladiators arena and a great big pile of handbags and fill it up with forum members

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Planning ceiling lights

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