In article , Mr.T wrote:

"Eeyore" wrote in message
...
You need at least a 23W CFL to match the output of a 100W incandescent.

Ony for a good one at the start of it's life. They get even dimmer with use
though.

The table here...
http://en.wikipedia.org/wiki/Incandescent_lamp#Power

Shows a 100W incandescent providing 1700 lumens.

I see 1710, 1730 and 1750 on packages having "standard" incandescents,
as low as 1670 for 750 hour soft white.

The lowest wattage CFLs I have seen produce 1700-plus lumens are the
Philips 25 watt SLS (1750 lumens) and 26 watt spirals.

In comparison some new CFLs I have claim only 1100 lumens for an 18W and
1200 lumens for a 20W.

I think some 18 watt ones produce 1200 lumens. A standard 75W
incandescent (120V 750 hour) produces 1190-1210 lumens. So optimistically
an 18W CFL in new condition will match that.

The 11W CFLs claim 600 lumens and that makes them only slightly brighter
than a standard 40W bulb instead of equivalent to a 60W as claimed.

I do wish they wouldn't make these silly claims for them.

They're probably comparing to an industrial service 60W incandescent,
which does indeed produce only about 600 lumens.

In my experience, a 13W CFL in new condition matches a 60W standard
incandescent when things are going well for the CFL.

The usual actual "standard incandescent" equivalences of CFLs in new
condition:

9W spiral - 40 watts

13W spiral - optimistically 60 watts
15W spiral - 60 watts fairly easily

18-20W spirals - 75 watts

23 watt spirals - between 75 and 100, good to perform as well as a 75
after they have aged or are running at non-optimum temperature.

25 watt Philips and 26 watt spirals - 100 watts

30 watt spirals - 100 watts after aging or when temperature is non-optimum

Me too, and those equally silly 8,000 hour claims.

That is for 3 hours per start in a 25 degree C ambient. This is the
actual industry standard for fluorescents. I think that a more
appropriate one for incandescent-replacement CFLs should be 1 hour per
start in a 40 degree C ambient.

Meanwhile, I do have CFLs normally last a few thousand hours.

- Don Klipstein , http://www.misty.com/~don/cfx.html)