Hi
This is a two part question
1 when installing a CFL bulb , do you size the bulb by the actual bulb wattage ? In other words , put a 40 watt CFL in a 40 Watt fixture . If so you can really increase the lumen output of the fixture .
2 Can you use CFL's in recessed fixtures ?
Made a quick trip to "Agent Orange" and the electrical salesman there told me , you can't use CFL's in cans because of the heat . it gets hot closer to the socket .
My opinion is that the socket is usually rated much higher than the fixture , so it would'nt matter even if it did get hotter .
If anyone has any facts or opinions on this , I would appreciate it .

As far as UL is concerned, you can use CFL's to replace similar-styled incandescents in any fixture that the bulb will fit into, up to the rated actual marked wattage of the bulb.

In theory, this means you can get "250 watts" of light out of a 60 watt (incandescent) fixture. That's in theory.
The problem is, the bulb most likely won't fit.

That's the real problem with recessed cans. Larger CFL's won't fit in the trim.

Problem is that the CFL electronic ballast (the plastic lump between the bulb itself and the screw in base) doesn't like heat. An enclosed fixture will cook the electronic ballast, and the bulb dies an early death. It won't (usually!) cause a fire or such, but people get unhappy with the bulb not lasting. The fixture will not get as hot as with an incandescent bulb, but incandescent bulbs didn't mind getting hot.

Yes, I've hear that .... and I'm not concerned. I have far too many restaurant customers using CFL's in their base-up totally enclosed cooking hood lights to accept that 'base up' is a problem.

Why do they use CFL's? Because they - even with the ones that die within a month - last a lot longer than incandescents in the same application .... and they're comparing the CFL's to 'rough duty' incandescents!

Reno's on the right track. CFL's that are 'base down' (majority of low price ones) do not like being 'base up'. The heat kills the ballast.

Along the same track as HID lamps that are position oriented, ie: base up/base down.

The CFL reflector floods should be marked as 'base up', situation is $$$.

I have put CFL's in customers cans before , and have not heard any complaints , does anyone have any practical experience that their life is reduced .
If so about how much , half , quarter etc ?

CDS.,

All it depending on which type recessed can luminaire it willbe if air tight more likey you will have issue than standard plain jane verison which they are not airtite and Non IC cans are vented in someway but with IC cans no it get pretty warm and with most CFL's with airtite cans I do see the screw in CFL have nasty early failure typically about anywhere from quarter of life to half depending on how it set up and how long it will stay on insteading of turn it on for couple minutes then off that is pretty hard on the bulb as well.

Merci,Marc

Ok
Thanks for all the input .
Like I said , I have put a few in , but in bathrooms . Consequently , limited use . That would explain why I haven't heard any problems . In the future , it sounds like I would be ok to install them when requested , and just qualify that the bulbs could have shortened life spans . Wouldn't the ballasts get just as hot inside a normal light fixture though. Also why would they make a par30 bulb if you can't put it in a can ?

I have been using CFLs for about 2 years now and they are failing at a fairly good clip. These are used quite a bit since they are on motion detectors.

CDS:
The 'PAR 30" CFL retro should be made to burn in a base up position. I suggest you read the info from the mfg., that should be with the bulb. A reflector style bulb, I sure would think should be a non-issue in a recess.

Keep in mind, a can should not be air-tite.

The problem with a CFL PAR lamp is the ballast is above the reflector so none if that heat gets radiated down. I assume they know that and design accordingly.

I have 26W CFLs in porcelain bulbholders in my garage. They are base up and the instructions call for base down. sometimes they get left on all night and I have not noted any apparent issues. Even being frequently switched the lifespan is still good.

As stated above, CFL's can be used in recessed cans and have been investigated by UL for use in a 6 or 8 inch diameter luminaire. The only restriction to this is if the lamp is marked and stated not for such use. You can find the entire White Book listing under Lamps, Self-Ballasted and Lamp Adapters (OOLR)

The stated lamp life for most fluorescent lamps is partially based on how often the lamp is turned on. I've heard that some brands will last almost as long as the stated life even when turned on and off frequently. Unfortunately, no one ever mentioned exactly which brands do well with frequent switching.