"The Medway Handyman" wrote in message
.uk...
"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.


Thats the info I was looking for. I reckon thats a good case for
dawn/dusk.

....
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.

True.

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.

Good point.

Just to spoil things, we have both, two 18W CFL dusk to dawn lights in the
garden one at the back door and one on the side of the shed at the bottom of
the garden, this provides sufficient lighting of the garden but nothing too
bright to annoy the neighbours, it removes all the dark spots and as such
there is nowhere to hide. Then we have a 150W halogen floodlight with PIR,
so if someone was to enter the garden and approach the house this provides
more lighting and acts as a detterrent, with nowhere to hide, perfect for
keeping people out! Also when we are having a BBQ the garden is nicely lit
without the harshness of a 500W spotlight.