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Lighting Help

Posted by dmarino (My Page) on
Wed, Feb 22, 12 at 12:51

Hello All,

This is my first post but I have been browsing for tip and hints for sometime now. I am in the process of redoing my den and would like to know if anyone can help with a proper lighting design. I plan on using 4" cans in the ceiling, but not sure if I should go with led or not. I would also like to accent the built in wall unit. I add a jpg of the room. Not sure what we plan on doing with the fee space. We may put another chair, or fish tank, or just leave it for the kids to play.

Thank you ahead of time for any suggestions.

Follow-Up Postings:

RE: Lighting Help

The Cree CR4 (led) works very nicely.

RE: Lighting Help

Hi thanks for the help. If anyone around that can help with the layout of lights.

RE: Lighting Help

The lighting requirement should be ~ 20 lumens per sq ft.
Assuming the use of dimmers and the main lighting coming from the cans (using CR4) each can will have an effective max output of ~546 lumens (Dimmers limit the max to 95%).

Total lumens required is 18 x 15 x 20 = 5400. Total number of cans required is 10 (rounding up). The number of cans could be reduced if you intend to have floor lamps and/ or other lighting fixtures.

Can placement (suggestions)
~ 30" to 36" from the wall.
~ 4' to 6' apart in a regular pattern. Use circular cardboard cutouts to mark out (approximate) the desired locations on the ceiling.

The exact placement is dependent on the location of the ceiling joists and other obstructions (hvac, electrical wiring, plumbing, etc) above the ceiling.

You will need to survey the space above the ceiling to finalize the layout.

The rules are similar to that for recessed can lighting in the kitchen.

For accenting the wall unit, look at the examples on

Here is a link that might be useful: LED recessed can guide for kitchens

RE: Lighting Help

I am not sure if I am saying this right or not but due led lights use low voltage or line voltage?

RE: Lighting Help

Sorry for my double post, but I was unable to find remodel housings for the LR4. Seems as if the LR4 family only has new construction housing.

RE: Lighting Help

The Cree LR4 and CR4 lights use line voltage.

At this moment, it does not make monetary sense to consider the LR4 (~$160) vs ~60 for the CR4.

The CR4 can be used in retrofit 4" housing that has a can depth similar to the H99ICAT.

Imo, if you have access to the space above the ceiling, it would be better to use new construction housing as the housing is attached to the joists instead of relying on the ceiling sheet rock for support.

The counter argument would be that retrofit housing costs less and could take less time for installation.

RE: Lighting Help

I am a true novice when it comes to all this talk. My plan now is to use regular 4in housing and just purchase led bulbs. Are CR4 the bulbs? I understand that the lifetime of the bulb will be shortened using this type of setup, but my budget is limited.

RE: Lighting Help

Yes the CR4 can be considered the bulb. The CR4 lamp like other similar modules (CR6, LR6, LR4) are intended to work specifically in recessed can housing.
Why do you think the lifetime of the CR4 will be shortened?

RE: Lighting Help

I was told by a rep for CREE that with this type of setup a the build can not dispense the heat properly which would decrease the life of the bulb.

Is it possible to use the same setup with a 5 in can?

RE: Lighting Help

No, to both.

Early generation high power LED emitters (ie- the chips) do have an issue with heat dissipation. This still manifests itself in high output LED flashlights which overdrive the emitters.

However, the LED emitters used in the LR and CR series are more efficient. Other reasons why there is no issue with using the CR/ LR series in recessed housings.
1. The protection circuitry (in the lamp) will dim the output when a temperature threshold is reached.
2. The lamp body (& trim) is designed to work as a heat sink for the LED emitters as well as a nice piece of trim.

The LR6 and LR4 (which pre-date the CR6/4 series) have very substantial heat sinks that proved to be unnecessary. Hence, the CR series body is substantially smaller and the lights cheaper than the LR series.

The CR4 will not fit securely within a 5" can.

Further comments

In the years I've operated CR6 and LR6 lights, I've not seen/ noticed the protection circuitry kick in, while I've had screw in CFLs burn out in other recessed cans.

Thermographic imaging shows that the CREE lights are cooler than even CFLs (E26 base - medium base screw in rated at 15W) in the same recessed can.

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