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jimmmy 12-29-2010 08:57 AM

How to lay out recessed pot lights?
Hello all. I'm new here and am sure that this question has been asked before. I am finishing a rec room in my basement and want to know if there is any rule of thumb for laying out pot lights.

Thanks Jim

JPraski 12-29-2010 09:05 AM

Not really. Pay attention insulation, which I presume you'll have none, and joists and that sort of thing. After that, you pretty much put them where you need the light. A nice option, if you have the room, are track lights, because you can move them around a little if you don't like where they shine.

That is, of course, the electrical answer- the interior designer answer, to make it look nice, isn't something I'm qualified to answer.

Speedy Petey 12-29-2010 09:20 AM

There certainly is a rule of thumb, but it involves a lot of variables, such as ceiling height and type or light used.

For a typical 8' ceiling and R30 sized cans teh rule of thumb is +/-5' apart and +/-30" from walls. This gives a proper spread of light down to the floor level for even lighting.
Now, this is for general pretty much even light. I must disagree with JPraski about putting them only where you need them. This can work sometimes, but usually you wind up with lights in random locations with no symmetry and a silly pattern of holes on the ceiling.
Sure, things like a game table or pool table should have lights right above, but I would NOT place lights over a chair let's say since furniture as we know can and does get moved.

I also disagree about track lighting for general lighting, especially with a low ceiling. Sure, track heads have come a long way in design, but I still cannot get over the whole 80's design feel of it. :sick:
As task lighting, for instance if you have artwork or pictures around the walls, it is certainly a good choice to light that.

AllanJ 12-29-2010 09:21 AM

For a starting point, sketch out a uniform rectangular grid pattern with the distance of a light nearest a wall to the wall to be half the distance from that light to the next light.

In my case I had to come up with some staggered trapezoid pattern because there were pipes and other things in the joists that I had to work around.

JPraski 12-29-2010 09:58 AM


Originally Posted by Speedy Petey (Post 558599)
I must disagree with JPraski about putting them only where you need them.

Sorry, 'where you need light' to me, meant evenly spaced and looking pretty and having light filling the area, not just spot lighting certain things. A bit unclear, and I appologize. Filling the space with light, and perhaps spot lighting important places, to me is more of an interior decorator thing. I am stylistically impaired, I get someone to tell me "Light this up", and then I ask them things like "Evenly? How bright?" and go to work.

For eveness, I would space them about 4-5 feet apart, with half that to a wall, but I like it a little brighter than some. It also depends on the lamp wattage / brightness, and the trim you use, eyeballs will make less diffusion so you'll need more, mirrored reflectors will make it so you need less, etc. Also, it matters what the cieling is made of. If you have a drop cieling with 2x4 panels, definitely use even spacing, it'll look funny if you do 5 foot spaces on 4 foot tiles.

clashley 12-29-2010 09:59 AM

The aforementioned rule of thumb (spacing of about 30" for 6" cans in an 8' ceiling, with 30" spacing for the wall) is pretty much correct for even general downlighting. You do need to consider a few things before you get started:

How much space you have available in the ceiling? You may need to use low clearance pot lights. Depending on what is above the ceiling (drafty airspace/insulation) you may need to use airtight or insulation-contact rated cans. Whatever cans you buy, make sure that they are individually thermally protected.

You also need to plan your layout around obstructions in the ceiling (joists, mechanicals, etc). Do this before you get started!

Finally, once you've determined a layout and number of lights, you'll need to consider the maximum electrical load these lights will require and plan accordingly. You may want to split the lights into zones that can be separately controlled. Consider using dimmer switches and/or three-way switches to make sure the lighting can be adjusted conveniently.

Good luck!

jimmmy 12-30-2010 11:15 AM

It looks like most of the info is the same on laying out the lights. The guy at home depot had said 36" from walls and 48" apart. He asked me how much light I needed in the room and if I needed it bright enough for reading. I said no that it is mostly a tv room. In that case he said that I should be fine with 4" . I'm not sure what the R30 size is mentioned above. What do you guys think about the size? I also saw 6" mentioned above. I would imagine that there is quite a difference in light from 4" to 6".

Jim Port 12-30-2010 11:58 AM

The 4" are more for accent lighting than for general room lighting. The 6" are good for room lighting.

jbfan 12-30-2010 12:30 PM


Originally Posted by Jim Port (Post 559177)
The 4" are more for accent lighting than for general room lighting. The 6" are good for room lighting.

4" cost more also!

jimmmy 12-31-2010 10:32 AM

Hey guys. I Hope your not going to disown me, I mean I asked for advice, you gave it, and I went in the opposite direction. Went to the store last night with intent on buying bigger cans and the guy talked me into smaller. They had a promo on 3" cans with gimbals and bulbs $40 for 6. The price is much better and I think at this price I will put in a few more than I had planned. I also think that they are small enough that I can fit some in my bulkhead and avoid a dark spot under there. The install seems a little simpler, he told me that they do not need to be fastened to any framework, that they can pushed up through the drywall and supported by that. What do you guys think about these lights?

Jim Port 12-31-2010 10:50 AM

I would have used the 3" in the bulkhead on a separate switch with the 6" used for the room lighting.

One of the things I did not go into was the circle of light given off by the 3" is much smaller than the 6" so many more are required. This quickly adds to the cost and the swiss cheese look of the ceiling.

JPraski 12-31-2010 10:53 AM

However, you do what's good for you.

the gimbals, or 'eyeballs', are more point directed, so you'll need more to saturate the area, but it will likely be brighter. Most of the can lights are made for that sort of install, the ones you got aren't really special. I thought that was what we talking about all along. You just need to make sure you get that kind instead of the new install, nail to the joist, kind. Also, 'rated for direct contact with insulation' is something to pay attention to, those are more expensive and it sounds like you don't need them.

I'm guessing around $10-12 each, so you got a decent deal, but nothing great enough to overcome any PitA these might cause. I don't see any problems, but if you do, go see what else they might have for what prices before you start punching holes.

Usually, these come integral with a junction box and all, you just run NM cable from the switch, to the box, and jumper to the next box, you're done. Even in the code, you don't need to nail the NM down if it's impractical, like in drywall (although it is considered practical to do it in a drop ceiling).

jimmmy 12-31-2010 11:28 AM

Thanks guys. I think I'm going to stick with these. I do honestly like the look of the smaller ones rather than the larger, even if there will be more used.

They are not rated for insulation contact. I was thinking about putting some insulation in the ceiling just for sound proofing. If I did, would there be anything wrong with doing that and leaving open space in say a foot each direction of the light location? It should still give me better sound proof than no insulation.

Jim Port 12-31-2010 12:04 PM

The non-IC housings require a 3" gap between the insulation and the housings.

Speedy Petey 12-31-2010 12:47 PM


Originally Posted by jimmmy (Post 559681)
They had a promo on 3" cans with gimbals and bulbs $40 for 6. The price is much better and I think at this price I will put in a few more than I had planned.

I hate sound negative, but I bet these are junk units. With respect to recessed lighting price should NOT be a major concern. Stick with name brand cans and you will be fine.
Get Emerald, Commercial Electric, or some other house brand and they are typically crap.

If a customer hands me Emerald cans I tell them I refuse to install them.

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