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CareBear
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Discussion Starter #1
8' ceiling, 65 watt equivalent LED 4" 2700K recessed lights. Dimmable.

I read that you want 1.5x the square footage in light wattage. 1.5x14x22 = 450 watts = 7 lights. That seems like less than what people usually recommend for that size of a area for 4" lights.

Any wisdom would be appreciated.
 

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The bulbs you're using should have a brightness rating in Lumens. Calculate the number of lights you need based on lumens per square foot. 20 lumens per sq-ft is a good number for general lighting in a living room or rec room - when it is supplemented by task lighting (lamp on end table for reading, etc). Of course, there are other factors. You'll probably need more than 7 lights.
 

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CareBear
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Discussion Starter #3
Thanks. 308 sq ft x 20 lumens per sq ft = 6150 lumens required. The lights are 575 lumens each, so that's 10.7 lights, which can be rounded up to 12 in order to arrange neatly.
 

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4" cans do not have a very wide spread of light----Why have you chosen 4" instead of 6"

You need to consider the spread as well as the lumens or you will end up with uneven coverage on the walls and work surfaces or floors/
 

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Licensed Electrical Cont.
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I would NEVER do 4" cans in a room that large for all around general lighting.

You're looking at 24 or so (depending on the pattern) if you did them for general lighting.

I would put them in sections or areas, not all over the ceiling.
 
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Trying to use a formula to determine lighting is ridiculous. With the frequent trendy thoughts going through the half a$$ed brains of interior decorators it's just impossible. Case in point. When the house was built, let's say light interior colors were the norm, and xx number of lumen s were sufficient. So as things change from light to dark, including furniture possibly or probably, now the lumen s need to be increased to xxxxxxxxxxxxxx.

Attempting to use a formula as such would be equal to doing a manual J for hvac but omitting building orientation and the number of leaking windows.
 

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CareBear
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Discussion Starter #8
@Fairview I think you can argue that calculations are non-optimal, but I don't think you can say that they are ridiculous. Using divining rods would be ridiculous.
 

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For even light spread they need to be about 6 feet apart---8 feet is typical for 6" cans.

Buy two and rig them up temporally to see what spacing gives you even coverage.
 

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CareBear
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Discussion Starter #10
@oh'mike thanks for the tip about testing two of them. I'm going to definitely need some 4" for the hallway, so it's not a waste to buy them if I decide afterall that I won't want 4" in the main room.
 

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People ask why 4" instead of 6". The reason is that 4" looks a lot better. 6" looks ugly and commercial. I haven't heard any designers or homeowners say otherwise, either. When I read the Home Depot reviews of these lights, there are people doing the same and they like it, such as http://reviews.homedepot.com/profiles/1999/248313813/profile.htm
I have 14 of the ecosmart 6" downlights (cree cr6) in my basement and I think they look great -- I also have a couple of the 4" you're considering (cree cr4) over a desk area. I did exactly as Oh'mike suggested. Bought a few and rigged them up with extension cords and Edison socket adapters to determine spacing.
 

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Wattage is not an accurate measurement of light output. Lumen output is, and is part of the lamp information. It will vary with fixture design, but most fixture manufacturers have this info available.
 

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We just put in 8x 13w CFL 5" cans in our new house's living room. I usually aim for about 4-6 feet apart (on center) @ 13watts for compact fluorescents. We're using 5" cans because we had 6" last time and with the small CFL bulbs you see the cheap galvanized backing if you don't have a fancy trim (which we don't because it's ridiculous to pay that price). 4' apart is very bright (our last house was 4' and light colored and it was too bright) for our ~8 foot ceilings, 6' is about right. If they're not bright enough, you can always get 18w bulbs, but I prefer a lower wattage, more evenly spaced is better for distribution. These are just my personal opinions and I like it a bit brighter.

 

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Child Alert! Pull Up!
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Neighbors kitchen remodel. I did (9) 4" recessed (dimmable). Looked great when it was finished. They originally picked out 5 or 6" baffled, and I said no, wouldnt install them.....so out dated!!! Ceiling wasnt painted yet in picture!!
 

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Licensed Electrician
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4" cans are for accent lighting, not main room lighting.
 

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4" cans are for accent lighting, not main room lighting.
I agree, in that I don't care for the very narrow beam that they send down. But that seems to be all the rage these days. A friend who's a lighting designer said that's 90% of what he puts in these days. My parents had them put in the kitchen, and the contractor also put them in the adjoining living room; which I agree is a bad choice because it makes light and dark areas. But they like the "look" (which will be dated soon), which doesn't have much to do with function, but aesthetics.

Nobody likes huge fluorescent tubes because they seem "too" diffuse, so they seem to go 180 degrees the other way and get these tiny spot lights everywhere. It's a trend and people like the small point source of light, but I think that's exactly the wrong place to use that type of light. If you want to use those under a counter, fine, but I'd still prefer a fluorescent strip for that use. If you're going for the contrast of light and dark areas (cozy?), maybe 4" cans work for that, but I'd prefer to see everywhere!

I think people have gotten a bad taste for fluorescent lights and are rejecting them subconciously. i.e. 6000k fluorescent 4' strip lights look terrible, I get it, but you don't have to go back to 1920's halogen point source lights to be retro. Sure restaurants want to be cool and use old school filament bulbs, great, I get it, but I want to be able to see when I'm in my house. Get some good color Rendering (>80 CRI) 4100k color temp bulbs and use them evenly distributed and you'd be suprised. I personally only use 4100k bulbs, 3500 isn't terrible, but 5000k just makes it washed out. fluorescents are like plastic, sure you can make cheap c$ap out of them, but you can also make nice things out of plastic; just make sure you're net getting c$ap bulbs. You want to pay 2$ for a CFL? you're gonna get short lived bad light. I just dropped $300 on CFLs from 1000bulbs.com on their TCP brand 4100k, 81CRI, 71 lumen/watt 13w bulbs for the house ~5$ a bulb. I've had them before, they last forever and I like the color.

Sorry for the rant, hope other people find this stuff as interesting as I do :whistling2:

btw, I think that kitchen fltdek did DOES look good, except I don't care for the hotspots that 4" bulbs, I know they aren't "cool" right now, but basically I laid out why I think so above.
 

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CareBear
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Discussion Starter #17
I've bought 4" LED and 6" LED lights and did some comparisons (Home Depot ecosmart). The 4" lights aren't narrow beamed by any means, as the pictures below show, and they had nearly the same average brightness that the 6" ones had. I tested a couple other 4" lights as well and they were essentially the same in terms of dispersion (actually a couple were slightly wider). Maybe some 4" lights are for spotlighting only, or maybe lights of the past were, but not any of these.

Home Depot ecosmart 4" and 6" recessed LEDs, 2700K, ~600 lumens, taken 8 feet from side wall:



4" dispersion. This was taken with an wide angle lens; the room is 15 feet wide:


6" light, which actually has slightly less wide dispersion:
 

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One thing you'll notice about the ecosmart 4" when using to light an entire room is that it will have a little more glare (vs the ecosmart 6") because the lens is closer to the trim ring.
 

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If you can get the same/more light from a smaller can, fine. That's great! Then treat them like a 6" can and don't install 9 where 5 would do the job.
 

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My point about the 4" cans being "narrow" was based on what most people put in those cans which is halogen Par bulbs, i.e. this:



Of course LEDs with different angled lenses may perform better. I REALLY don't like for 2700k bulbs non-continuous spectrum bulbs ,i.e. LEDs or Fluorcescent. I think they're trying too hard to imitate incandescents, when they're totally different beasts. Check out the chart below, incandescents display a continuous spectrum (not straight thought), which renders an object naturally (albeit a bit red compared to the sun). But anything that doesn't "glow" from heat, is using phosphors, LEDs are actually blue with white phosphors. Fluorescents are UV with phosphors. I have seen some terrible interpretations of incandescent 2700k by LED and fluorescent. Anyways, 4100k is the only color bulb that is "legal" on a car with HIDs (many people put cr4p blue bulbs which aren't legal though), and it's a perfect balance of color. Of course not everyone agrees, but I really don't see why people pick such a red/yellow colored light. I'll just put that out there that I used to be a moderator of a lighting forum, so I have quite a bit of background and opinions on lighting!

http://en.wikipedia.org/wiki/Color_temperature






 
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