How to calculate the amount of LEDs needed for a 4x5m room

ledsunky

Newly Enlightened
Joined
Jun 23, 2017
Messages
3
Location
Hanoi, Vietnam
Hello!
I need to install some new leds for my bedroom. Room size is 4m x 5m, so please ask how the number of downlights to use is calculated how?


Thank you!
 

Ken_McE

Flashlight Enthusiast
Joined
Jun 16, 2003
Messages
1,687
find out how many lumens they generate and then choose them the way you would light bulbs.
 

MeMeMe

Banned
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Aug 27, 2018
Messages
125
Hello!
I need to install some new leds for my bedroom. Room size is 4m x 5m, so please ask how the number of downlights to use is calculated how?


Thank you!

Generally people don't have their bedrooms very bright, 300 lux at the high end, 100 at the low end. As you can always dim lights, I would start at the high end. 300 lux * 4 * 5 = 6,000 lux. If you have 600 lumens/fixture, then you need 10. If you have 800 lumens/fixture, then 8. You may be drawn to high output fixtures, but with down lights you need more for good lighting.

Personally I don't recommend the new flat/flush mount ones ...where you just see a small flat panel light source. They are trendy, but really not the best lighting as they have higher glare. I prefer something inset which will hide the direct light source from most viewing angles.
 

MeMeMe

Banned
Joined
Aug 27, 2018
Messages
125

If you are doing paper work in 50-60lux, you are not doing your eyes any favors. If that is the lighting level in your bedroom, you should have task (reading, stand-lamp, etc.) for reading, paper work, etc. If you put the lights on a dimmer, which is nice for the bedroom, then having it bright and adjustable is a nice way to go. If it is too bright you can dim it. If it is not bright enough, your only option is major damage to your ceiling and/or a bunch of wall-plug lights you may not want.

DON'T put 30cm*30cm or larger panels in your bedroom ....for one, they are not terribly attractive, two, they have high glare, not something you want in your bedroom. They are really intended for use where lighting levels are higher reducing your glare perception (like a kitchen). The Hue is a nice concept and the ability to control CCT is really nice in the bedroom. However, you are not going to want to look directly at 2200 lumens coming out of a 30cm*30cm panel, or even 4000 lumens even out of 1x4 panel. Yes you can dim it, but to achieve good lighting distribution due to your likely ceiling height, you would want 4-6 units so you are going to be starting with a lot of light.

These flat panel lights are really "in" right now. They have a high cool factor and they are actually quite cheap to make, but that does not make them good light sources.

Size makes little difference .. lumens/area + distribution is what contributes to glare, and most of ones linked are fairly high powered.
 
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