For new construction you should first check out a recessed CFL fixture (usually 5") instead of trying to force a generic CFL to work in a fixture designed for a halogen PAR reflector lamp.

Go to a good lighting store and ask what is best for your installation and switch/dimmer arrangement.

Mighty, thanks!

It's a remodel, not new construction. I know there are several dimmable CFL's out on the market at the moment. I suspect more and more will make their wave with the new mandates.

I may just have to do this trial and error and report my findings....

Check with Halo first to be sure CFL's will work with the incandescent recessed cans.

Several people here have reported favorable results with Greenlite brand dimmable CFs.

I've done well with Philips brand. I haven't used any of their R lamps, but I don't see any reason they'd be different from the ones I have.

Examples here and here. This is not an endorsement of the supplier - I know nothing about this vendor ("Black Energy").

David, many thanks - I've made copies of those two.

I have a true basic question - what is the difference between R20 and R30 bulbs? Would R30's fit the 4" cans?

The number after the R is the diameter of the lamp in eighths of an inch. (Ah, for the metric system! <ducking>)

So an R30 is 30/8 = 3.75" in diameter. An R20 is 20/8 = 2.5" in diameter. A PAR38 is 4.75" in diameter.

I'm not a fan of recessed lights so I don't have direct experience, but I expect you'll probably need an R20 for 4" cans. Others here may have more informed thoughts.

David, thanks once again and you are correct. I will be needing R20's for 4 inch cans. I haven't found any dimmable CFL's so I suspect they are slow in appearing.....

From reading this thread and the parallel one you've got going in the kitchen forum, it looks like you seek a dimmable fluorescent reflector CFL that will fit in a 4" can that was designed for incandescents. I think you're going to have to let go of some of those requirements.

If you're using cans designed for incandescent bulbs, then the trims available for those cans will also have been designed for incandescent bulbs. With 4" cans and trims, I'm afraid you may not be able to use a cfl larger than about 15 watts, and even that is likely to stick out of the can in an odd way. Dimmable cfl's seem to be a bit larger than equivalent non-dimmable cfl's, exaggerating this issue.

While a 15W cfl produces a fair amount of light, it is nowhere near as focused and directed as an incandescent reflector bulb such as a PAR halogen. As a result, these might do a fair job of providing general/ambient lighting but they won't do a good job of putting intense task lighting on the countertops, though undercabinet lighting can help here. To light the counters well from recessed cans,you'd need higher-wattage cfl's, and that probably means larger cans.

There's also the issue of whether you even like the look of dimmed fluorescents. When incandescents are dimmed, they don't just get dimmer; they also change color, swinging even more towards the warm end of the spectrum and providing the familiar candlelight-like glow. Dimmed fluorescents , from what I've read, just get dimmer without changing color. I can imagine liking this in certain circumstances, but then I like cloudy days too. Not everyone does.

On top of this, standard cans are not designed to make the most of the light from fluorescent bulbs, and will likely waste some of the light you're striving to produce efficiently.

Having recently wrestled with the lighting in my own kitchen, my feeling is that some of the lighting should be dimmable but not all of it needs to be. In your position, I think I might give up on the idea of dimming the cans, use 4" or 5" cans that are designed for fluorescents -- I know there are 4" fluorescent cans that will take an 18w bulb, and 5" that will do 26w -- and pair them with dimmable xenon undercabinet lighting. The cans would provide bright, diffuse general lighting, and the UC's would provide intense, dimmable task lighting.

Lots of great information there Jon. Thanks.

It seems I may have to opt having regular halogen bulbs in the 4 inch cans for now - maybe? The plan is to order regular halogen and perhaps order one dimmable CFL to see how it looks. The 4 inch incandescent cans have already been ordered and will be installed tomorrow or Friday. I wouldn't want to delay this any further. If I like the way the dimmable CFL works, then I'll buy those instead. I have already purchased Juno Xenon Pro undercabinet lighting so that will definately help for tasks. These will go in next week as soon as the cabinets are in place. I've learned a lot about lighting with the help here.
Thanks so, so much.

I don't mean to hijack this thread, but I am facing a similar problem. My ceilings are sloped, so I need sloping cans (I hate eyeball reflectors). I can't find a sloping 5" can made for florescents. Can I purchase cans made for incandencent lights and use reflective compact florescent bulbs in it?

Let me suggest that if you're married to cans, you consider using helical or tri-tube dimmable CFs, rather than CFs in the R-flood format. You'll have more choices.

Some folks think it'll look bad, with the bare CF in the can; but a friend of mine has done it and she says nobody even notices. How often do your guests stare at the ceiling, anyway? (No wink-nudge comments, gents, I didn't mean it THAT way. ;-)

That is a good point, and they cost much less. I can always install a couple and see how they look before ordering enough to do the whole house.

I can also give that a try as well.

RE: "When incandescents are dimmed, they don't just get dimmer; they also change color, swinging even more towards the warm end of the spectrum and providing the familiar candlelight-like glow. Dimmed fluorescents , from what I've read, just get dimmer without changing color."

Just for for the record, from experience: Greenlite's dimmable R40's, of which we have 16 in 3 different rooms, are 2700k. Just like an incandescent. They have the same warm color at any dim level, and look just fine.

And they do stick slightly out of the can. But, as was pointed out earlier, nobody spends time looking at the ceiling. Except an architect who was over with a friend a couple of months back, and proceeded to lecture us on lighting and how halogens would "look cleaner," and didn't stop to ask first who was paying the electrical bills!

You had me chuckling about yor architect friend. Seriously, what gives anyone the right to do that? lol

Please Help, I too am in CA and am desperately trying to find 4" fluorescent "remodel" cans, at a REASONABLE PRICE, I CAN'T afford $50 each. Anyone got a source. I am sorry I cannot offer any advice. I am too Busy fighting with the City!!!!!!!!!

Mark, you might consider using larger fixtures that produce more light, so you can buy fewer of them and still get the job done.

What about these: http://www.1000bulbs.com/product.php?product=33543
or these
http://cgi.ebay.com/R20-WHITE-90-LED-Narrow-Angle-Light-Bulb-E27-110V-PAR20_W0QQitemZ200142476078QQihZ010QQcategoryZ20706QQrdZ1QQssPageNameZWD1VQQcmdZViewItem

There are no good dimmable CFL in the market which funtions well with smooth dimming. The only lamps that I know that dimms well (smooth) is Litetronic's Microbrite lamps. These are Cold cathode CFL lamps which are twice the life of ordinary CFL lamps, and saves more $$$. You can find all these lamps in www.litetronics.com