# lighting calculator



## rubberduckey (Mar 29, 2015)

I am installing sloped ceiling lighting in a mono roof what we call (whistler style home around here) its a high residential ceiling upto 17 feet high. There are four rooms of concern that generally differ two feet in hight. I am not so much concerned with what type of lighting as I have decided on a 6 inch sloped can with par 30. My frustration lies in the inability of my wholesaler to make any recommendations on spacing. I have tried a few online lumen calculators that adjust to dimensions and desired lumens for the intent of the room and have come up with quite different result. Is there a free lighting calculator out there that anyone could recommend? 
Thanks in advance.


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## telsa (May 22, 2015)

Give us a break.

Over illuminate -- and slap on some dimmers for the LEDs.

Job -- DONE.


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## rubberduckey (Mar 29, 2015)

Ya sure, Ill give ya a break. Leg or arm? If its thats easy what would an average spacing be for that height? I have no idea as I have never installed pots at that height.


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## Navyguy (Mar 15, 2010)

This is what I generally do... but you need the specs of the light to know what the distance of the cones is at the work plane...

http://recessedlighting.com/recessed-lighting-spacing/

Having said that, I am a fan of over lighting and controlling with dimmers as was suggested. But I use this approach to get a base number, but it will always go up from there.

Cheers

John


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## wildleg (Apr 12, 2009)

if you are doing any substantial work, your supply house should be able to hook you up with a lighting rep that can give you guidelines.

if it is small, you are on your own, or alternatively, you could throw it back to the contractor/client and their design professional.


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## rubberduckey (Mar 29, 2015)

Ya thats the thing wildleg, I guess Im just a small fry because they are not being very helpful. But thanks for that info Navy guy thats helps at least give a guy a rough idea.


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## wildleg (Apr 12, 2009)

throwing it back on the client can be beneficial in many cases, and it doesn't have to be in a bad way, either. If there are contractors, designers, or architects involved, it is a no brainer to send them an RFI requesting help or confirmation that what you have estimated is acceptable, etc. If you are asked for your opinion, or dealing direct with a homeowner, you can also tell them that even though you are experienced, you are an electrician and an installer, and encourage them to get ideas from lighting showrooms, etc to make sure they think they will be getting the lighting that suits them best, obtain more ideas, get more creative, etc.

of course, as others said, you can always deal with too much light easily.

with higher end clients, you have to try to make sure you have given them enough crazy high end stuff, lighting for art, under bar rails, and all the other idiotic stuff, besides plenty of light, wall washing, task lighting, etc.

there will always be something you have to add later; its just the way it is.


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## sbrn33 (Mar 15, 2007)

rubberduckey said:


> I am installing sloped ceiling lighting in a mono roof what we call (whistler style home around here) its a high residential ceiling upto 17 feet high. There are four rooms of concern that generally differ two feet in hight. I am not so much concerned with what type of lighting as I have decided on a 6 inch sloped can with par 30. *My frustration lies in the inability of my wholesaler to make any recommendations on spacing.* I have tried a few online lumen calculators that adjust to dimensions and desired lumens for the intent of the room and have come up with quite different result. Is there a free lighting calculator out there that anyone could recommend?
> Thanks in advance.


Why would it be the wholesalers responsibility to design your job?


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## rubberduckey (Mar 29, 2015)

Not asking for design but some manufacturers recommendations might be not too much to ask?


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## Helmut (May 7, 2014)

My frustration lies in not having any room dimensions to work with.


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## Helmut (May 7, 2014)

I'd bet 8' spacing would work.

I'd ditch the par 30 bulbs, and use a led retro-fit with a swivel insert. 65W equivalent.

Need dimensions, height of slope at lowest point, height at highest point, room dimensions, windows, ect..... to do it accurately I suppose.


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## MikeFL (Apr 16, 2016)

Every supply house has lighting reps who will help you with that. Hook up the rep with the owner and let them select a package. He's going to take them for all they got and you'll make bank.


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## rubberduckey (Mar 29, 2015)

Not getting any real response from my wholesaler so I used an online calculator and adjusted my spacing where needed. Im more of a substation guy and haven't done a lot of those types of installs. But it seems like it should work well enough. Ceiling is 17 sloping to 15 in living room and 15 sloping to 13 in kitchen and dining. Don't have the prints on me so I Cant give a lot of dimensions at the moment. But I definitely went heavy on the lights in the kitchen.


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## Helmut (May 7, 2014)

rubberduckey said:


> Not getting any real response from my wholesaler so I used an online calculator and adjusted my spacing where needed. Im more of a substation guy and haven't done a lot of those types of installs. But it seems like it should work well enough. Ceiling is 17 sloping to 15 in living room and 15 sloping to 13 in kitchen and dining. Don't have the prints on me so I Cant give a lot of dimensions at the moment. But I definitely went heavy on the lights in the kitchen.



You got a 2' slope, over what distance?

2' slope over a 20' wide room isn't anything to worry about.

20'x20' room, 15' cieling....I'd throw 2 rows of 4 hats( 5"), 11W led trims, and I'd guess you'd be somewhere around 50fc at desk height.

Maybe 3 rows of 3.....(6")


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## splatz (May 23, 2015)

These are some pretty amateur rules but how about if you try just spacing no more than half the ceiling height between lights and start about a third of the ceiling height from the wall.


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