On 27/09/2017 15:10, Bill Wright wrote:
On 27/09/2017 14:57, wrote:
When I re-furb'ed my last house I fitted window switches to all
accessible windows and external doors, so didn't need to bother with
PIRs. The current house already has a "professionally installed" alarm
with PIRs and door contacts, but no window contacts.
I was going to replace the PIRs with (a large quantity of) window
switches but am having second thoughts because of the unsightly wiring.

SWMBO is concerned about staying with the PIRs because, if we set the
downstairs ones at night, of what happens if someone goes down for a
drink or a wander around in the night. How does everyone else cope
with this?

I'm wondering whether it's viable to set-up an external boundary
around the house using infra red or laser beams/detectors (above
animal height). Has anyone used this technique?

Personally I'd forget window contacts. They do false alarm if there's a
gust of wind or a bird hits one. The actual units (Vipers etc) are prone
to damp. The wiring is very labour intensive unless it's done at first
fix stage in a new building. It is possible to make it invisible but
it's hard work.

PIRs are generally OK as long as they are wired (not wireless) and are
dual tech (microwave as well as IR).

I have external beams to protect the parking area. They're pretty good
for that purpose, but not for protecting the house when you aren't there
because of perfectly innocent callers (unless they send a silent alarm
to your phone and/or run the CCTV). The type with two independent
parallel beams are best.

With all alarms remember that one false alarm means that everyone within
earshot will ignore your alarm for the next ten years.

Bill

I was thinking of using sealed reed switches (which is what I used in
the previous house) - how do they get affected by damp?

The existing PIRs are wired, but aren't "animal proof" so I need to
either replace them or change to switches. The problem is still what
happens when people wander about in the night when the alarm is set.