In message .com, gmw
writes
I have just used a photographic exposure meter to compare the light
output of a CFL bulb with various pearl light bulbs.

The CFL is a 20W bulb claimed to be equivalent to a 100W bulb. It has
had about 1 year of evening use.
Its measured light output is a little LESS than a 60W 2000h pearl bulb
rated at 555 lumerns, and ~40% of a 100W 2000hr bulb.
Interesting but you need to take into account the spectral response of
the human eye. As a general measurement it's valid though.
Power ratio for the same light output is thus 1/3 not 1/5. This is a
66% over claim in this case.
If you check the light output spectrum you'll see they emit significant
amounts of UV light (skin cancer and cataracts anyone?) compared to
incandescents which emit virtually none.

If you look at the current waveform of a CFL you will also find that
they are some of the dirtiest appliances on the market in terms of
electrical interference, some can actually stop ADSL from working IME
and you can forget listening to MW/LW and SW radio.

You can buy PFC types which are 'nicer' but they are generally not
available or cheap.

Efficient they may be but environmentally friendly they aint, the
chemicals used to manufacture then are toxic, they contain toxic
chemicals (mercury and phosphor plus others metals in the tube, lots of
nasty stuff in the electronics) so they need *proper* disposal not just
dumping in the bin when they fail.

As for the light output, I tried three CFLs in one fitting without
telling the LTLP, each and every time she commented on how dim the light
was or how it looked 'murky' in the room. The original incandescent was
an Asda 60w pearl BC. I tried an 11w no name CFL, a 17w Phillips CFL and
a 20W GE CFL. They all were slow to 'warm up' to full output and the
light produced was unpleasant and had noticeable colour bias.

Frankly, not nice. Roll on LED technology. No warm up time, much longer
life than CFL, much nicer colour rendition, dimmable and you can manage
the colour temperature much more easily than CFL technology.

I *do* have CFLs in two places where a failed bulb would be difficult to
change or failure could be dangerous but they are not places where I
spend any time so the light quality is not as important but I'm not
going to be buying any more until they are much better.
--
Clint Sharp