Will my room look nice if I illuminate it with LED strips?

July 7, 2013 9:57 PM

I have a large room that I would like to illuminate with LEDs. I'm thinking of putting a ledge around the the walls about 45 cm / 18 inches from the ceiling and laying LED strip lights along it, directed upwards so they bounce off the walls and ceiling (which are painted white). Would this look weird? Would it light the room adequately? I'd make the ledge with a groove in the top surface so that you can't see the LED lights from floor level.

Technical details:
The room is about 5.5 meters / 18 feet square; the ceiling is about 3 meters / 10 feet high.
The LED strips I see for sale say that they give off 400 lumens of light in a beam 120 degrees wide.

posted by Joe in Australia to Home & Garden (14 answers total)

My first thought is that LED light tends to be rather cold, and most spaces and people don't look particularly attractive bathed in the light of an LED.

But if you could solve those problems, sure, why not?

A lot of restaurants light with tiny (possibly LED?) lights bounced off the ceiling. It's also the underlying principle behind track lighting.
posted by Sara C. at 10:01 PM on July 7, 2013

As long as they're in the 2,700–3,300 K color temperature range to give a nice "warm" color, and they are enough to provide your illumination needs, I think they'd look fine.
posted by 2N2222 at 10:16 PM on July 7, 2013 [4 favorites]

I'm actually thinking of doing something similar in my living room, but I was thinking instead of a ledge I'd put small crown molding that would be 2 or 3 inches from the ceiling, and containing RGB tunable LED lights so you can use a controller to change the light color and intensity to anything you like. It should give an effect similar to this.
posted by barc0001 at 10:35 PM on July 7, 2013 [1 favorite]

A 40 watt incandescent bulb is 500 lumens. I would think you'd need quite a few of those strips to get anything like reasonable lighting if it's indirect.
posted by Chocolate Pickle at 10:44 PM on July 7, 2013

I think Chocolate Pickle may have a point. I use indirect lighting in my (small) living room by pointing torchier lamps at the ceiling. I currently have 8 regular (60w) bulbs on and it's just light enough for my taste, which is bright but not super-bright.

I think what you'd end up with in this case is very low "mood lighting." As always with lighting, the only way to figure it out is to just experiment til you like how it looks.
posted by drjimmy11 at 10:55 PM on July 7, 2013

That's one of the reasons why I want to try tunable lights, to get the right levels of light. My living room is dominated by a projector screen anyway that's running about 2000 lumens worth of light so for me it's more for overall ambient lighting.

That said, if you're interested in blowing the doors off, there have been some serious enhancements in the output of these strip LEDs lately. For example, this strip which I didn't even see for sale 6 months ago when I first looked at doing this, will allegedly do nearly 900 lumens per linear foot, or almost 14,000 lumens across its entire length. I'm kinda having trouble figuring out what you'd use that kind of power for residentially, but maybe you have a backyard you want to play touch football in on summer nights and slapping a couple of these on the eaves would be a quick and easy way to recreate the noonday sun?
posted by barc0001 at 11:10 PM on July 7, 2013

I've considered this for our livingroom. Last I considered it, things were still too expensive for an experiment, but prices have continued to drop since.

You can get LED strips that put out 300 lumens/foot. If you ran them alomg just 2 of your walls, that would be over 10,000 lumens, which is like having 6 100W bulbs, which is quite a bit of light.
posted by Good Brain at 12:00 AM on July 8, 2013

If you take a scientific approach to it then your question is actually quite a complicated one. The best place to start your calculations is to work out how much light you want to cast onto the main body of your room - you can then try to work back to consider the ceiling you plan to bounce the light off, the light fittings you are going to use, the distance they will be from the ceiling and finally the colour and brightness of the bulbs. This guide to LED Luminaire Design and this more general lighting design considerations guide (PDF) may help. Your most safe approach might be to buy the brightest strips you can find - but to use dimmable ones - like this demo.
posted by rongorongo at 2:44 AM on July 8, 2013

Total anecdote, sample size N=1, but I did this exact same thing in my dining room in my house in NY when I lived there, and I loved it. It was subtle and cozy.
posted by digitalprimate at 4:20 AM on July 8, 2013

I've got a friend who did pretty much exactly what barc0001 suggests. The result is mood lighting, not utility lighting, but it is nice. You really want to have the LED elements on the tape hidden from direct view, because they can be unpleasantly dazzling when you look right at them.
posted by adamrice at 6:55 AM on July 8, 2013

The trick is finding a product that is not too expensive and has a reasonable density in terms of lumens per foot.

Ended up with ... I think it was this, http://www.ebay.com/itm/151033170669 which was actually about half what I needed in terms of lumens/foot, but running two parallel strips ended up being cheaper than most other options.

I would point out that there are a lot of places that sell LED strip lighting that is actually the stuff that you can buy on eBay direct from China ... just at a significant markup. So be sure you consider that if you want to keep costs reasonable.

See for example,

http://www.ledwholesalers.com/store/index.php?act=viewProd&productId=902

which appears to be the exact same thing I received, minus the power supply, and I'm unclear on what the extra $75 is buying me.
posted by jgreco at 7:57 AM on July 8, 2013

I plan on doing this in my bedroom. I don't think you'd get enough to light the room, but if you do a google search for 'led crown molding' or 'lighted crown molding' you'll find lots of ideas and instructions. I think hiding the lights behind angled crown looks a lot tidier than just putting strip lights on a ledge.
posted by elsietheeel at 8:01 AM on July 8, 2013

With a room as big as that, it will probably seem dark in the middle. The hot-spot of the illumination from your strips will be either at the wall/ceiling corner, or if you engineer the railing carefully (tilt the strips inward but still keep a little lip to shade your users from direct view of the chips) maybe a foot or so in from the edge.
If it were a point source, we'd say it spread out in both directions, but for the strip, we can approximate it as only spreading out laterally. So by the time it gets to the ceiling 18" away (at 120-deg angle) it's covering a spot 12" x 62" (except really only 12"x(31-40") of that will be hitting the ceiling, the rest will wash up the wall). Note that by the time you get ~3-4 feet from the wall, the ceiling will not be getting much light at all, making a dark spot in the center of the room.

You'd think that you could say 18 feet*4 walls=72 linear feet of lighting *400lm/ft = 28,800lm total output, and just divide that by the floor area (30.25 sq meter) = 952 lux. That might be the average brightness of the ceiling, though it would be much brighter in the corners of the room and much dimmer at the center. In fact, unless you pointed the strips way into the center of the room, almost half the beam pattern would hit the walls before the ceiling, so we'd either need to increase the surface area of where hte light's actually hitting (30.25 m2 ceiling area + 11 m2 wall area (that's 18"x72feet) = 41.25), and/or throw away some of the light entirely, depending on the paint color on the walls. The reflectivity of a white non-textured ceiling is usually assumed to be 90%, walls anywhere from 40-90%. That gives you about 600-700lux averaged on all surfaces above the rail strip.

For work spaces (tasks, writing, cooking, chopping, etc)design standard is ~500 lux on the surface (actually 1000-2000 for specialized stuff); for average office lighting (think conference room) more like 300lx, and home lighting can vary from as low as 100lx for moody dining or cozy living rooms, up to 500lx in the kitchen. (reference)

If you had an infinite ceiling at 650lx, the floor brightness at 10 feet away would also be 650lx. A 5.5m room is not infinite, so there will be more losses (light from ceiling bouncing off the walls instead of going toward your occupants) as you get farther from the ceiling. Still, you'd probably be above the 300lx cited as standard for home illumination.

That's a lot of made-up numbers, but I hope it gives you a general idea.

In reality, it's more qualitative than quantitative. I think it would give you a pleasant indirect glow lighting, and while it wouldn't be too dim for most purposes, the feeling of the space would be thrown off by the darkness of the center of the ceiling. Also, the best lighting designs don't rely entirely on a single light source, and mix direct with indirect light. You might want to consider other lamps in the room, or a central light fixture (chandelier, ceiling fan, standard flush or semi-flush fixture), depending on the purpose of the room (living, dining, bedroom).
posted by aimedwander at 8:22 AM on July 8, 2013 [2 favorites]

Ive seen this done on cabinets. An example of how to make it look hideous here.

Even when they use white lights, it isn't enough to illuminate a space, and the effect it gives is sort of 1980's lounge vs interesting lighting.
posted by haplesschild at 8:50 AM on July 8, 2013 [1 favorite]