In article ,
"The Medway Handyman" writes:
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?

Obviously an 11w CFL dawn/dusk will be on for a much longer period, but is
low energy, won't be triggered randomly & will have a longer service life
PIR lights being a PITA IMO (sorry Rob)!

On the other hand a 500w halogen PIR in theory will be on for much shorter
periods, but will consume much more power.

Again in theory an 11w CFL could be on for 45 times as long for the same
energy.

So which one is the best deal for the customer?

Depends what the customer wants. However, if an 11W CFL is good
enough for the customer, a 500W halogen was never required in
the first place. An 11w CFL is nearer to a 40W light bulb.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]