"The Medway Handyman" wrote in message
.uk...
Someone recently described a 500w PIR flood light as "fixing a half bar
electric fire outside".

Which has got me thinking. Especially given the unreliability of 500w
halogen lamps/lights.

So, given the choice between a 500w PIR halogen & an 11w CFL dawn dusk
light - which will be cheaper to run?

I would use dusk to dawn lighting myself. That would be on for near enough
5,000 hours per annum, which would use the same electricity as a 500W PIR
controlled lamp running for 18 minutes each night. So.it all depends upon
how often the PIR is likely to be triggered and how long it is set to be on
for when it has been triggered.

.....
So which one is the best deal for the customer?

Another consideration is that the PIR triggered light shows that there is
movement in the area. On a patrolled factory estate, that can draw the
attention of the guard from quite a long way off, so the application is
important in deciding which is the best to use.

Personally, I prefer to have low power lamps on at all times. PIRs can be
fooled, but an always on light leaves anyone trying to break in constantly
illuminated, which is a useful deterrent in itself.

Colin Bignell