The following link has more information. Title24 mandates that you install gu24 cans or cfl cans which will not hold e26 base incandescent bulbs.

Here is a link that might be useful: Led can light guide

Thank you, David!
I have just finished reading the link to your review - very helpful. I also saw several of your replies to similar questions that answered some of my concerns and were very educating. Do you mind if I pick your brain a little more:

Since our project will be technically a new construction (no can housings was installed anywhere in the kitchen) to be compliant with california code:

1. Does can housing need to be airtight and satisfy ASTM E283 2. IC rated? we will have insulation (batts) in the attic after ceiling is done
3. what type of connector must be in this housing to comply with california?
4. will it work with dimmable switch
5. what difference does the size of the can make - on # lights, restrictions, overall price of housing/bulbs
6. can you suggest a model that I can look at by going to HD/Lowes?

As for what goes into these cans - what is the difference between LED and LED trim?

I realize that these are dumb questions and information/answers have been provided on this forum to most of them - but I wanted to get California-specific answers that are scattered all over the posts and unfortunately I am running out of time. I am also confused with the industry lingo...
Thank you very much for your help!

Dax

David, this is one of your comments from 2010. Is it still applicable in Oct 2012

Posted by davidtay (My Page) on Tue, Oct 5, 10 at 16:38
I would go with 6" cans for the following reasons
1. 4" cans have less space for heat dissipation.
2. 6" cans are more common and you have more lighting options.
3. The light coverage is better for 6".
Since you're subject to title 24, you'll have to install CFL cans with integrated ballasts or LED cans with GU 24 base / anything other than edison base.

I ended up with LED cans as I figured that
1. Cans with integrated ballasts would become problematic when the ballast fails as someone would have to gain access to the upper part of the can to change the ballast.
2. I was drawn to the CREE LR6 @ LampsPlus as there wasn't any glare like the other CFL cans beside it.
3. The cost of a CFL can + trim + CFL bulb was higher than a CREE LR6 + can ~ 1+ year ago. Today the costs are more favorable for a CR6 (GU24) + can ~ $80.
4. The LED cans are dimmable using standard incandescent dimmers.
UCL is very useful.

Last time I checked, the dining room doesn't have to have GU24 sockets. Like other living areas, it either has to be high efficacy (fluorescent or LED on the official CA approved list and in an approved type of non-screw-in socket), or be on a dimmer. So just use a dimmer and install Edison base cans and buy CR6/CR4 or the Home Depot Ecosmart version, and save $20 per can while keeping options open. Screw-in CFL doesn't qualify (unless on a dimmer).

In the kitchen itself, adding a dimmer doesn't satisfy the T24 requirement, so you are stuck with fluorescent or GU24/LED for the majority of your lighting watts.

There are adapters that let you convert a screw in socket to a GU24 -- these do not satisfy the requirement to not have screw-in in the kitchen, even if the conversion is "permanent". GU24 socketed cans are/were not T24 approved for CFLs either.

The 4" CR4 looks (to me) a bit better than the CR6, but costs more. Also, the CR6 gives you the option of using the brighter 800 lumen version.

As of today:

CR6 575L about $45, both screw-in and GU24
CR6 800L about $55, both screw-in and GU24

Ecosmart 6 inch LED at HD (local, San Jose) $25 screw in, $40 GU24. There seems to be no difference from the CR6, except warranty is 3 years instead of 5.

Attofarad, thanks for all the tips!
Our dining room area and kitchen are essentially one room and are separated by peninsula with cooktop. In this case am I still ok with dimmer and Edison socket in the housing for DR only? Kitchen eventually will get the GU24/AT/IC housing as per code.

(I think Attofarad and I must shop at the same Home Depot...)

When we reconstructed our house four years ago, we designed our kitchen to be part of a great room that includes an informal dining area. Only the kitchen part needed the high efficacy lights. We were forced to use Title 24-compliant CFL cans because at the time, LED was not as price competitive as it is today. However we did the breakfast area and the rest of the great room in normal incandescent and halogen on dimmers. Now that LED technology has come down so far it price, I have been retrofitting LED where it makes sense.

So I think your electrician is giving you fine advice to use cheap cans and the CR-6. It is really a great product. We have 18 of them now, and may eventually add another 14-15 of them to replace the CFLs in the CFL cans.

WWS944 - thank you. I see now how I was mistaken about the advise from our electrician. I looked up housings on HD website and looks like model H7ICAT from HALO might work. Will let the electrician call the shots though.

1. Does can housing need to be airtight and satisfy ASTM E283 Yes

2. IC rated? we will have insulation (batts) in the attic after ceiling is done

Yes

3. what type of connector must be in this housing to comply with california?

GU24 or some other non E26 base.

4. will it work with dimmable switch
That is more a concern with the actual lamp installed. The Lutron Diva CL is highly recommended and works well with the CR6, CR4, RT6, RT4.

5. what difference does the size of the can make - on # lights, restrictions, overall price of housing/bulbs

The 4" cans are typically more expensive than the 6" equivalents. You need to price out every part to get a good idea of the total cost, what is more cost effective vs what you can afford to splurge on.

The number of lights depends on the output of each lamp vs the total sq ft * desired illumination per sq ft.

6. can you suggest a model that I can look at by going to HD/Lowes?

You should look for something like
http://www.polar-ray.com/Cree-RC6-12W-GU24-6-Inch-Housing-GU24-Socket_p_127.html

If I were to redo my lighting today, I might consider using 4" cans with the CR4.

thanks, davidtay
will be looking for these modesl over the weekend at HD.
dax

Re: glare - Cree offers optional trim rings for the CR6 in your choice of three anodized dark colors plus black plastic if you find the standard white trim too glaring. These work on the HD Ecosmart version as well. They add almost $15 to the cost of each though. The CR4 can be purchased (in the Cree-branded version only) with a shiny silver trim as well as white.