In article , Graham. wrote:

"Derek Geldard" wrote in message
.. .
On Sat, 18 Aug 2007 13:46:15 -0700, wrote:

wrote:

I have understood that switching fluorescent lamps - tubes - on and
off was not a good idea and that they should be switched on and left
on. Unlike filament lamps which do not seem to mind.
How do the modern CFLs compare/suffer etc etc?? I know that they can
take a minute or two to warm up and maximise their light output.
If they should be switched on and left on, then they begin to defeat
the very purpose of having energy saving CFLs fitted.

a popular myth

Which one?

Could you point out please the particular myth you refer to?

http://www.wiki.diyfaq.org.uk/index....scent_Lighting


Could you expand on that? It's a rather large webpage but all it says
on lamp life is :

"Tube life depends on type of ballast (& starter where used), and how
often the tube is switched on and off."

Which is correct but not specially helpful.

BTW Mr. Meow. we had another CFL fail yesterday after 6 months service
in a cap down open fitting. It was a Feit electric 23 watt spiral
offered for sale promising a 5 year life. The phosphor is quite
significantly darkened and the top of the plastic end cap containing
the electronic ballast has been toasted brown, what happened to the
cheap Chi/Taiwa-nese pcb assy inside is anyone's guess.

A five year life would be 5*365*24=45,800 hours
I_don't_think_so.

Why do GLS lamp manufacturers give an honest average
lifetime in hours (say 2,000) but with longer lived CFL lamps,
you have to find the small print that qualifies the headline figure.

One for the ASA IMHO.

In the "States", many CFLs have limited warranties for 6 or 7 years or
whatever in "normal home use". The packages also clearly enough state
actual operating hour life expectancy figures - usually 6,000 to 10,000
hours. That is in lab conditions including 3 hours per start at 25 degree
C ambient and average figure, so I suspect some significant number to burn
out at or before 3,000 hours due to randomly fairing worse than average,
running less than 3 hours per start, or running where it gets a lot hotter
than 25 degrees C. I suspect based on some experience that averages may
be 4,000-6,000 hours in most home use.
The so-many-years figures could get more conservative if more users
request the manufacturers to make good on the warranties, which I suspect
few do.

- Don Klipstein )