Overhead Lighting


Hi All...

I am trying to design lighting for our living room / home theater. I'm thinking of using MR16 bulbs or maybe PAR20, but I can't figure out how to space the recessed housings. Does anyone know how to figure this out?

Distance from fixture to surface, taking into account the bulb characteristics gives a good guide.

For example, R30 bulbs on an eight foot ceiling need 6' for 100% overlap. Note, that's three feet from walls.

Found this on a quick Google.
gregoryx said:
Distance from fixture to surface, taking into account the bulb characteristics gives a good guide.

For example, R30 bulbs on an eight foot ceiling need 6' for 100% overlap. Note, that's three feet from walls.

Found this on a quick Google.
Wow, I googled for days and didn't find than, thanks!

But won't the bulb type have a lot to do with it? I have 7.5 foot ceilings, and I installed 4 inch recessed 50W R20 bulbs (line voltage) and we think it's just not bright enough in there. These are spaced about 31 inches apart (dictated by the joist spacing in my older house).

It seems that spacing housings 6 feet apart won't provide much light at all. Also, how do I know how many total watts I'll need to provide sufficient light in the room?

Thanks very much...
I believe 4" cans are usually designed more for accent lighting. If you use the 6" cans with R30 bulbs it makes a huge difference. 6" cans 6 feet apart (like gregoryx stated) gives plenty of light in a room even with a 7.5' ceiling. Also with the 6" cans you usually can install larger bulbs like 65 watts.

The other thing to keep in mind is that you want to be using flood lights, not spot lights.

The Pod

With 6 inch cans I can go to 120W floods. My wife prefers smaller cans and I tend to agree, the 6 inch ones do look kind of clunky. I was thinking of 5 inch cans with 75W PAR30 bulbs for general lighting and a few more, but with MR16 bulbs, above the seating to use as reading light.

The PAR30 floods have a beamspread of 42 deg, so the coverage is 5.8 feet on the floor. I could use 50W or 75W bulbs.

Is there any rule of thumb about how many watts it takes to light a room of a particular size?
There are can lights in my basement. On mine, you can adjust how deep the bulb is within the can. The further out out, the more of a spread you get on the light. I think they look better deeper in the can, so it just took some playing around to get it right.

I'm sure there are numbers that tell you how many watts are needed, I'm sure this type of computation is done by designers all of the time. Where to find it, I don't know.
Brightness is a matter of opinion; coverage is less so.

I think poorly designed lighting is WAY too common and it's painfully obvious when I walk into a house or room that some silly "designer" (all too common in our area) picked the lighting locations willy-nilly and some silly electrician followed the lead, more or less.

In fact, when the electrician started cutting holes for our lighting, he had markings that left up to 1" error. I told him to go do something else while I plotted them all out with a .5mm pencil and drilled the pilot hole. :)
End result: beautifully covered lighting that goes as un-noticed as carefully chosen paint colors and careful attention to detail on moldings... except that the end result is pleasing even if one can't say just why.

I think the best "look" (and ideal in terms of heat and brightness and such) is 6" cans (such as Cooper / Halo's 7ICT stuff at a mere few bucks each at Home Depot) with an attractive baffle and bezel. I prefer simple in those categories, but that's just our style. There's some shots of one room here. There's more stuff here if you click into "Remodel" or "Home Automation" and poke around. You can see them going in a bit in "Remodel".

The decent fixtures have auto-shutoff if they overheat, so if you put the wrong bulb in, you'll know it.

I run Philips 65w bulbs in the 6" cans I put in our current house. I followed the 6' rule, since we have 8' ceilings. When decent dimmable CFLs are available at a decent price, I'll probably move to them. I've seen them encased in what looks like an R30 body, which I think looks much better than the curly-cue in the socket.

I use 100w R40s in entryways and hallways in 6" cans.

I use 4" cans for art-lights in every room and for sinks and potty in the one bath we've remodeled. I started with AC 4" but have replaced many of them with low-voltage DC now. The DC light is wonderful for sinks and desks and such.

Note also that you can adjust the depth of a bulb in the can. I keep the R30s recessed a bit in most areas but recessed a LOT in the master bedroom as it softens the light a lot. the R40s are actually running at or beyond the edge of the bevel; hence one light for a given area - though with as many as three sets of art spots in a single stair landing, so there is no lack of light if desired.

I run all the lights with Insteon switches (previously on X10 Switchlincs) and they turn on to 70% bright or less - except the R40s, some of which are 100%. This gives a softer look and leaves room to get brighter with a second tap on the switch. So... back to your last question, I guess that's somewhere in the 45w per 6 square feet of floor, capable of 65w - plus the art lights that are anywhere from 2x25w to 2x50w and at least one pair per room.

HTH a bit... should'a put that on my site, I guess. :ph34r:
Thanks again to everyone.

Based upon the input here and discussions with my wife, I have figured out the plan below. Im still up in the air about alot of this, but I need to order stuff by Thursday so I'll be making a decision one way or another very soon.

I agree completel with the sentiment that poorly designed lighting is annoying. So I'm trying to do my best to avoide having it. I would appreciate any questions on the proposal below.

The room is 21 by 11 feet with a 7.5 foot ceiling, so light won't spread as far as with higher ceilings. 18 fixtures arranged in 3 rows of 6 fixtures per row. The first row is 2 feet from the back wall, and the next two rows are spaced 4 feet apart (but the spacing along the 21 foot dimension is 3.5 feet). This makes the fixtures look even. The baffles will all be black stepped, to try to reduce glare (I hate glare). The room has two pocket doorways into it, one at the front end and the other near the middle. The TV is going between them, so it’s off center. It’s a Samsung plasma, which is 4 feet wide (I forget the official screen width – 50 something).

Five of these fixtures will have low voltage MR16, 74W lamps with a 36 deg beam spread. These are designed for reading when people are sitting on the couches that are right below the fixtures. The beam spread will cause light to appear across the entire length of the couches, although the fixtures are spread too far apart to have the light even across the entire span. These 5 will share a 1,000W Vizia RF dimmer and probably not be used except when task lighting below the couches is needed.

The remaining 13 fixtures will contain 50W PAR20 lamps with a beam spread of 42 degrees. At 7.5 feet, that puts the half power light at a little over 2.5 foot radius. With the fixtures spaced 4 feet part, that will cause the light to overlap as it weakens and, I think, should provide relatively even lighting across the entire floor. If I use ICE PAR bulbs that should help more, I hope.

Since the room is so long and narrow, the three lights at the extreme end away from the front will have their own dimmer and probably not be used too often.

That leaves 10 fixtures. I am trying to decide how to be able to have a little lighting for TV watching without having glare on the TV. My idea was to split these remaining 10 lamps into two zones. The six in the middle could be their own zone, while the two in the very back of the room and the two in the very front but about 3.5 feet from each edge of the TV another zone. I am hoping that these, because of their angles and distance from the TV, when dimmed won’t produce a glare in the TV screen.

My concerns:

I am worried about the lamps that are on glaring on the TV, even though they will have the stepped baffles and a beam spread that should keep them away. Any ideas on how to prevent glare?

I expect that the PAR50 lamps will provide enough light, although they do poorly in my kitchen. Then again, those are R50, not PAR50 so the PAR lamps should produce more light. The numbers say it should be more than enough light, but I’ll be adding fixtures to my kitchen during this project in an attempt to brighten it up a bit, since it is just too dark. With these housings, 50W in a PAR20 is the max I can go. I expect you’ll all say it’s plenty of light, or too much light. Please let me know your thoughts on that.

The PAR20 bulbs will be fairly warm from a color temperature standpoint, creating a reddish effect similar to incandescent. That should be okay, as this room is already brighter than the kitchen, which has a very dark floor and countertops.

The PAR20 lamps make quite a bit of heat and they are not recommended for ceilings less than 8 feet high. We have R20 50W lamps in my kitchen and we have not noticed an objectionable amount of heat from them. Still, these are PAR lamps, not R lamps. Does anyone think there will be a big difference heat wise?

The MR16 lamps should produce a much whiter light suitable for reading and such, and much more light per watt. But the uneven nature of how it’s laid out on the couch is a bit of a concern.

Good quality MR16 lamps should send 85% of their heat up, not down with the light. Of course, I live in a two-story house, so I am essentially sending the light up into the ceiling, which is the floor of the second story. The housings will be non-air tight, although I have not looked into air tight housings to see if I should use them yet. Comments on this?

Finally, I am thinking of just using 75W MR16 bulbs everywhere. They can be dimmed most of the time to whatever level everyone likes and there would be no question of there not being enough light (like a blinding amount). The heat would go up, not down (which is either a bug or a feature – I don’t know which). The whiter light color would make the colors in the room look more natural without shifting them to the reddish end of the spectrum. It’s a bit more expensive. This adds about $230 to the lighting project.

Maybe instead of 50W PAR lamps I could use 50W Low Voltage MR16 lamps. This would be less light and whiter color.

So may options…

Thanks everyone!