"tim..." wrote in message
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"Rod Speed" wrote in message
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"tim..." wrote in message
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Hi,

My new abode is in a block of flats that has interior lighting provided
by (60) bulkhead lamps which are mostly on 24-7 (with some controlled by
light sensors so as only on when it is dark)

I have been tasked with looking to see if we can replace some of then
with ones which detect movement so that they can be off for the large
parts of the day when no-one needs them

It seems that the style of lamps that we have now is not currently
available and I suspect there will be resistance to having different
style of lamp along the corridor so it's replace all of them or none of
them

Currently the bulls we use are 2 times 7W CFLs and the smallest LED
replacement that can be styled with "Integrated" movement sensor is 10W
so replacing those lamps which will need to remain on 24-7 is going to
be negative (after the cost of installation ahs been taken into account)

So the end result of changing all of the lamps has to result in a very
significant saving from the ones which are going to go on-off overnight,
for this to be worthwhile.

Adding external PIR sensors into the supply is going to be a mess
(especially as the corridor was only recently redecorated and there's no
way that redecorating afterwards can be justified) so is it possible to
obtain just the internal microwave sensors and have them installed
inside the lamps that we currently have - there is plenty of space for
this.

Anybody have an experience of this.

The Philips Hue system would work well in that situation because
its all in the bulbs themselves so easy to just use those in the
existing bulkhead lamps. And the movement sensors are
completely independent, not wires to them at all, entirely
internally battery powered and communicate by wifi/zigbee.

but we don't want to have some system controlling when it goes on and off
we want it to work that out for itself

Not clear what you mean by that. The movement sensor
is programmed when you set it up, tell it what lights to
turn on or off when a particular sensor is triggered by
movement etc.

BUT they arent cheap and so you are unlikely to save enough power to pay
for them.

Makes more sense to use LED bulkhead lights and leave them on all the
time IMO.

we have 14W bulbs in at the moment

the LED equivalent fittings come with 10W bulbs, the saving is trivial and
not enough to pay for the fitting costs.

even putting the smallest LED bulbs I can find in the current fitting
(4.5W) barely covers the difference in price between the CFL at 1.20 and
the LEDs at 6 quid

though as the LEDs come down in price that will change

But you are unlikely to save enough electricity to
pay for any form of movement sensor so might
as well just leave them on all the time and put in
lower powered LED bulbs as the current ones die.

Shouldn't be hard to calculate what they would
cost to run 24/7. We can't do that because you
don't say how many there are.