Chris Bacon wrote:
Ian Stirling wrote:
Surprised to find large quantities of "2 for 1" 99p 18W/100W CF bulbs
by Philips, in Morrisons.
They claim 7000 hours.

IME all "CF" lights, the sort that replace incandescent ones,
are rubbish. Why does the output drop off so quickly? Why do
they take time to brighten fully?

The second one is partially due to reducing the amount of mercury in
them.