In article ,
"Dave Plowman (News)" writes:
Just why are these so expensive? 13 quid in B&Q...

I presume you are refering to the 23W GE Genura?

The price of these has simply never dropped, unlike all other
compact fluorescent retrofits. These were a new technology
when they were introduced some 10 years ago -- they are
electrodeless. Since failure of fluorescents is most commonly
due to failure of the electrode coating material, that mode
of failure is avoided and they last much longer. Also, the
losses associated with the extra voltage drop at the
electrodes is eliminated, making them more efficient.
When these were introduced, they were the only compact
fluorescents which were brighter than the lamps they intend
to replace whilst also being barely any larger. This might
still be the case even now. These lamps will carry on running
until either the control gear dies (a random effect, but
dependant on running temperature), or the phosphor wears out
and the light gets too dim to be viable. I had about 50%
still running after 20,000 hours, back when they only claimed
a life of 8,000 hours, although they were noticably dimmer
than new ones. Last time I noticed, GE were claiming a life
of 15,000 hours on the boxes.

Having been one of the pioneers of electrodeless lamps, GE
mysteriously stopped developing them after releasing this
first product, but has nevertheless continued manufacturing
the Genura. They would probably sell a lot more if they
dropped the price, but I'm sure if you do the calculations,
the lamp is still well worthwhile.

BTW, it's a flood lamp, not a spot lamp. It has quite a
prononced run-up, starting at something like 50W equivalent
light output, and increasing to over 100W equivalent in a
minute or so (although I haven't bought any for ages, so this
might have changed). Also, there's no switch-on penalty on
lamp life -- you can switch it on and off as often as you like.

There are folded tube R80's aroud now of course, but I don't
think any of them match the Genura's efficiency, light output,
and size match to a real R80, although some might have slightly
more directional beams.

--
Andrew Gabriel