On 22/08/2019 15:11, Martin Brown wrote:
On 22/08/2019 14:28, Andrew wrote:
On 22/08/2019 13:57, Pancho wrote:

I think cost is about 1 £/watt/year. Given how rapidly technology
changes I'm dubious that paying for more efficient equipment would be
cost effective.

My PIR light is plugged into a cheap mechanical timer to switch the
whole thing off from 1AM to 4PM, else it just sits there in daylight
using about 20 watts

That's a hell of a standby load. My LED PIR is battery powered by 3 C
cells and lasts about a year at the front door which is in daily use.

It is quite a surprise how much some things can use in "standby".


It's a 40 year old Smiths bulkhead lamp with a PIR hanging underneath
and circuit board inside. It hasn't failed unlike a more modern
unit.