In article , Jon Weaver
writes
My Conservatory is finally finished (Which I am sure you will be glad
to hear means no more questions)

I am thinking of fitting a PIR sensor off of my house alarm, just to
give me that extra bit of protection.

Is a PIR a good idea in a construction like this.

As the temperature will fluctuate, could this trigger the PIR.

But more imporantly, because its almost entirely glass, can a PIR "see
through" the glass, to anything moving outside?

I haven't tried it, but would have thought that you would get lots of
false alarms due to sunlight & temperature changes. PIR's always say
"don't point at a window", well you can't really avoid that in a
conservatory.

You can get "dual technology" detectors which combine doppler radar &
PIR, that might work.

--
Tim Mitchell