How much light for living room?

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Old 02-27-10, 04:23 PM
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How much light for living room?

Ok, as one of my upcoming projects, I am going to be installing recessed lighting in my living room. It is currently ony lit with a fllor lamp on a switched outlet, and my son has already knocked over and broken two of them.

In any case, before I get to figuring out the wiring, I am trying to figure how how much light is necessary. I do some lighting for a living, but I design street lighting and the local jurisdiction tells me how much light they need for th streets. I can do lighting calculations for interiors also, but have no idea how much light is adequate for a living room.

Right now, I have my living room laid out with 4-6" cans, 13 watt CFL's, giving me an average of about 5.5 footcandles over the room. Is this enough? The room is an L-shape, about 19 feet long overall, and 11.5' wide on one leg and about 7.5' wide on the other leg. I have 2 lights in each leg (I also have a separate design with 6 lights overall, but lower wattages and it gives me a little more light overall).

Any thoughts if I am in the target range for the right amount of light? Linked below is the design for both options.

http://i237.photobucket.com/albums/f...oomFeb2010.png

Thanks,
Neil
 
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Old 02-27-10, 05:27 PM
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For comparison, office buildings general work lighting is between 30-50 fc. IMO your rooms are much too dark. Since your going to use CFL's, dimmers might be an issue.

I suggest option 1 and adding another can so you have two rows, of three cans each. I would also use all 6" cans due to cost and the amount of light.
 
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Old 02-27-10, 05:58 PM
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Toyln,
Thanks for the response. The lighting program I use at work (and used for my living room) is Visual Pro. In there, it has some lighting level recommendations from IESNA, which agrees with the 30-50 footcandles you stated for offices. However, it also states only 5 footcandles for residential, general. If you drill down to detailed tasks (sewing, reading, etc.), it steps it up to 30 footcandles or more I believe. Since I am looking for overall ambient lighting, do you really think I should aim for 30-50 footcandles? Seems high, but I admit that I do not know what a footcandle looks like (wish I had a light meter, but too much $$$ for the limited use I would have for it).

I am also trying to keep in mind glare from the lights, so I laid it out with one row almost directly above the couch along the long right-hand wall on both plans. The other row was spaced equally and also was placed assuming a 50 degree cutoff angle fromthe fixture. This puts it so that, if you are sitting on the couch, you won't be able to see the bulb.

I actually have 2 rows of 3 cans each for Option 1 (planning on 6" cans for all), just one of the lights was offset closer to bottom of the steps to the 3rd floor (upper left corner). The main living area is where the 4 lights are located in Option 1.

I wasn't planning on dimming the lights, just looking for good overall general ambient lighting. When I get into it, I may purchase cans with dimming ballasts from Lithonia or someone, but they are $$$ compared to the cheap Halo cans at Home Depot.

Thanks for the help and keep it coming guys!

-Neil
 
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Old 02-27-10, 06:18 PM
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Just for giggles, I took Option 1 and changed the bulbs to all 18 watt (1200 lumen) or 23 watt (1600 lumen) CFL's. Average jumped to 11 and 12 footcandles, respectively. Not much difference between the 18 and 23 watt layouts in terms of light levels.

Also took a second look at the IESNA recommendations in the program. For residential (general lighting) it recommends 5 footcandles. For residential (entertaining, general conversation and relaxing) it only recommends 3 footcandles. Not until you get to reading or specific visual tasks like table games does it start to recommend 30 footcandles or more.

-Neil
 
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Old 02-27-10, 06:56 PM
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Originally Posted by rockford33 View Post
Toyln,
Thanks for the response. The lighting program I use at work (and used for my living room) is Visual Pro. In there, it has some lighting level recommendations from IESNA, which agrees with the 30-50 footcandles you stated for offices. However, it also states only 5 footcandles for residential, general. If you drill down to detailed tasks (sewing, reading, etc.), it steps it up to 30 footcandles or more I believe. Since I am looking for overall ambient lighting, do you really think I should aim for 30-50 footcandles? Seems high, but I admit that I do not know what a footcandle looks like (wish I had a light meter, but too much $$$ for the limited use I would have for it).
No, I don't think you should shoot for 30-50. I was just using that as a benchmark. Kind of "your office is this much, your living room should be this much" thing.

Originally Posted by rockford33 View Post
I actually have 2 rows of 3 cans each for Option 1 (planning on 6" cans for all), just one of the lights was offset closer to bottom of the steps to the 3rd floor (upper left corner). The main living area is where the 4 lights are located in Option 1.
I ment two rows of three cans plus the one to the left.

Originally Posted by rockford33 View Post
I wasn't planning on dimming the lights, just looking for good overall general ambient lighting. When I get into it, I may purchase cans with dimming ballasts from Lithonia or someone, but they are $$$ compared to the cheap Halo cans at Home Depot.l
I agree with you about dimmers. You can get dimmable CFL's but cost and performance are a down side. This is also why I suggested 6" cans. You will be able to raise or lower the light level to your liking by changing the lamps like you did in your program. Also, more cans with smaller lamps will give a more even light.

The big thing about lighting is there are so many variables it is hard to get the perfect plan. You have to take in the type of room, color of walls, carpet, furniture, ceiling, Age of the occupants, time of day, and just personal preference. Seams to me that 11-12fc would be better, but I like light.
 
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