LED Downlight - Distance from a joist

[Adam]

I've spent the last couple of hours planning where to put some LED downlights in 2 rooms. They are both quite small rooms so I'm going with 4x in each. I had to shift my calculations a few times due to the joists which ran pretty much bang on where I wanted to put them. Because the rooms are fairly small (2.7m x 2.4m) I'm a bit restricted by where I can place them without them being too close to the walls or too close to the middle.

What's the thinking regarding the distance the downlight can be from a joist? The closest would be around 25 - 30mm away from the joist. As LED's don't give out too much heat, is this acceptable?

 

[HardwareGeek]

The manufacturer of the down light will give a minimum distance in the installation instructions, the least i've seen so far was 50mm most prob say 100mm (halogen was 100mm too), but in reality it will be fine at 25-30mm

if the ceiling has insulation make sure you leave space around the light for air to let it cool or it will die quicker than its supposed to, driver burn out etc

 

[Mercenary Keyboard Warrior]

In my kitchen the spark managed to install 2 out of 6 downlights so close to the joists that they actually have slight chunks taken out of them from the holesaw, more awesome trades work

They had 50watt halogens in them so when I swapped for 4w led I didn't stress too much. The lights I use do have the fire caps already on the units though, cost a fraction more than open back ones, just seemed a no brainer as was what the sparks manager at work said he would fit.

Just a note, make sure you buy fire rated ones, they have a little disc in them that will expand to seal the unit against the ceiling should they need to.

 

[jpaul]

Is your led layout based on a led with a particular beam angle ? or even, a specific bulb you already identified

 

[Adam]

Ok based on the replies and what I have read, even with the LED's I might move them in towards the middle of the room by 30-40mm to give me some space between the joist.

Is your led layout based on a led with a particular beam angle ? or even, a specific bulb you already identified

Not really, I wanted them far enough from the wall not to create shadows and a reasonable distance apart.

These are the ones I have, I bought a load for my kitchen and have 9 left over: http://www.ebay.co.uk/itm/MiniSun-F...hash=item2100b438e1:m:mSdcC4SEYiQCisL0PrrmzQQ

 

[a1ex2001]

Did you buy there bulbs as well? Personally when we did ours recently I went for quality integrated units as it just seems more sensible than relying on retrofit bulbs in a legacy fitting. They should last 15 odd years by which time tech will have moved on sobulb replacement wasn't high on my list?

 

[Adam]

Did you buy there bulbs as well? Personally when we did ours recently I went for quality integrated units as it just seems more sensible than relying on retrofit bulbs in a legacy fitting. They should last 15 odd years by which time tech will have moved on sobulb replacement wasn't high on my list?

Yes I did. 20x downlights and 20x LED bulbs came to just over £100. They have been great so far although only fitted for the past 2 months so probably a bit early to tell.

 

[jpaul]

They should last 15 odd years

I guess they have a lengthy guarantee then, and a low profile fitting.

Bulb tech in terms of efficiency is improving (I suppose law of diminishing returns though when >100lm/W),
but moreover hopefully higher CRI value bulbs will be available cheaply, that is my main reproach of current Led bulbs, they have the instant on convenience,
but not the >90cri colour of metal-halide uplighters 70W/6000Lumen

 

[a1ex2001]

7 year guarantee and decent but not stellar Cri (Halted H2 pro 550t) they are lovely compared to the gu10's we had in our old kitchen. I can't see hi cri getting mainstream in decent fittings for a while and when they do I'll swap out the units.

 

[Amp34]

I guess they have a lengthy guarantee then, and a low profile fitting.

Bulb tech in terms of efficiency is improving (I suppose law of diminishing returns though when >100lm/W),
but moreover hopefully higher CRI value bulbs will be available cheaply, that is my main reproach of current Led bulbs, they have the instant on convenience,
but not the >90cri colour of metal-halide uplighters 70W/6000Lumen

There are a fair few LEDs that provide >90 CRI. But you get what you pay for, both in terms of flicker (especially with dimmers) and colour rendition.

The lack of decent high CRI integrated fittings is one of the reasons I went with non integrated units.

 

[a1ex2001]

There are a fair few LEDs that provide >90 CRI. But you get what you pay for, both in terms of flicker (especially with dimmers) and colour rendition.

The lack of decent high CRI integrated fittings is one of the reasons I went with non integrated units.

Interesting, what bulbs did you go for in the end? You definitely get what you pay for with LED's cheap ones and dimmer switched for example are a nightmare the Hallers units we went for dim really nicely which was a key feature for us.

 

[jpaul]

I was aware of Phlips master colour and expert which are available in cri90+ at 4K and 3K gu10, 5years - interesting they are currently ~£10, much cheaper than I thought eg
(philips corrupted the master name with the postfix "value", but the link is the real thing)
and (after a recent discussion on filament bulbs in led thread) well-lit £20 a go
- both a bit rich for me