In article ,
George E. Cawthon wrote in part:
Don Klipstein wrote:

Maybe but my experience with a 13 watt CF with the bulb facing downward
to replace a 60W incandescent was not encouraging. Lasted a few
months and went fizzle.

I think that 13W should at least usually work OK in such fixtures, even
though subjected to non-optimum highish temperatures.
More likely I expect 13 watt compact fluorescents to usually work at
least reasonably OK in downward-facing fixtures.
Also - brand *may* make a difference. There are the "Big 3" brands -
GE, Philips and Sylvania (in the USA) - and I have noticed some general
trend of better quality with those brands.

Check for any warranties, even if limited. If the warranty requires
mailing back dud lightbulbs and remedy is limited to replacement with more
of the same, I advise to take them up on that!
If a major manufacturer thinks they can fatten their bottom line by
cheapening a lightbulb design by a few cents, I suspect they will back off
if merely hundreds of customers send back dud lightbulbs! The manufacturer
would not want stockholders to get wind of mailroom overtime or need to
hire another mailroom worker along with threat of loss of a percent or two
of market share resulting from a design using a capacitor cheaper by .6
cent or a transistor cheaper by 1.2 cents!

No way would I attempt to replace a 60W incandescent with a 30W or even
a 22W CF.

30W - I would guess probably a problem.

26W - I would guess good chance of conking out noticeably early in a
small enclosed fixture rated 60W max incandescent or a downward facing one
rated 60W max incandescent.

23W - probably not compromised too badly for better brands. But I would
say worse for 24W (which in my experience most 23W ones improve upon) and
worse-still 25W. But in my experience 26W is brighter and 25W does not
outshine 23W, so I expect 25W (which I already had bad experiences with
for 2 brands even and saw less of more recently) to have more trouble
than 26W.

22W - I have yet to see one.

18W - next lower size of spirals where I noticed more recently and with
higher efficiency - apparently replacing spirals of 19 watts of about 2-3
years ago and 20W spirals of about 4 years ago. So I expect 18W to be
pretty good, 19W fair and 20W maybe touchy.

Then there are the Philips SLS models - triple-arch rather than spiral.
The 15, 20 and non-dimmable 23-watt ones are even outright rated to be
used in recessed ceiling fixtures, and the 15 and 20 watt ones are even
available with snap-on reflectors of 2 different sizes.
(The 25 watt and dimmable 23 watt Philips SLS are not rated for use in
recessed ceiling fixtures.)

- Don Klipstein )