Intruder alarm upgrade - old vs new sensors

[Larches 2]

The time has come to update our house alarm (to address a few issues and get better functionality); we've found an installer that we're happy with, but could do with a bit of help in deciding how extensive the upgrade should be.

 

The current system is based around a Risco Eurosec CP8, fully wired with PIRs, door contact and shock sensors on a couple of windows. We will be swapping to an internet-connected system with wireless capability and adding a couple of extra sensors in new locations. The installer has proposed an Orisec system and is willing to hook this up to our existing wired sensors if we want to keep the cost down, but perhaps unsurprisingly he says it would be preferable to replace all the old sensors at the same time. I can see the point of this, in that there is presumably less chance of something going wrong if the system is set up with all-new kit, and the installer could then guarantee the whole system (for 1 yr) rather than just bits of it. On the other hand, with new sensors something like £48 for wired up to nearly £80 for wireless dual tech, this increases the total cost considerably, and at least some of our existing sensors appear to be working just fine.

 

As such, I'm stuck in a bit of a quandary over spending extra just for the sake of it, versus potential false economy if there's a risk of the old sensors not working well with the new system or becoming unreliable due to age. Obviously I could just see how it goes and replace them as problems arise, but I'd rather not end up paying a £60 callout fee or whatever, plus potential fault-finding time and new sensor cost, when I could have just opted to refresh the sensors in the first place.

 

Trouble is, I've no idea what age our current kit is (some pics attached), as it was here when we moved in, getting on for 8 years ago. Some may even be from when the house was built (mid-90s). There is one sluggish, ancient-looking PIR which we'll definitely replace, but the others seem to work fine, as does the door contact (presumably little to go wrong with that). We have a couple of old Viper window shock sensors which seem pretty unresponsive (e.g. LED doesn't react if window frame is hit quite hard - only if you tap the sensor itself!) but then I know the sensitivity is adjustable, so maybe that's all that would be needed (perhaps re-fixing too, as there's a bit of play when nudging them).

 

The questions that occur to me are:

 

1. Is there such a thing as 'typical lifespan' for PIRs? I'm guessing this could vary quite a bit by model. Presumably they won't last forever. One guy told me the Fresnel lenses can go brittle after a while, degrading their reliability.
2. For the window shocks, our options are to get the existing ones tested and tweaked (again, not sure of their lifespan), or to replace them like-for like (wired), or to upgrade to wireless ones - if they are any good? Reason for considering is that one window is quite wide and the existing sensor is tucked away in the corner, so may struggle to pick up vibrations from the other end. With a wireless one, we could place it in the centre of the frame. We need it to be not too sensitive though - e.g. don't want the alarm going off if the window cleaner comes round when we're out.
3. Can anyone think of other pros/cons for replacing the working sensors or leaving them in situ as a hybrid (old/new and wired/wireless) system?
4. What's generally the better bet for a conservatory - a combo door contact + shock sensor, or a dual-tech PIR? I guess the shock sensor could deter a break-in before much damage is done, but there's maybe a risk that someone could attempt entry at a point other than the door and therefore evade that sensor. Apart from the roof hatch, the opening windows are very small, though whether anyone would try breaking one of the larger (non-opening) panes, I don't know. Yes, we could have both, but that would come to about £150 and the costs already seem to be mounting.

 

I'd be grateful for any thoughts/advice on that lot - thanks.

 

 

 

 

Edited February 6 by Larches

[Geoff1946 145]

In your circumstances I would definitely replace the lot. Nothing lasts for ever and it appears your kit could be 10 to 20 years old.

PIR sensors, (the clever bit within the unit), become electronically noisy with age, reducing their performance whilst increasing probability of false alarms.

Door contacts use magnets, which gradually lose strength, and reed switches whose contacts degrade.

 

Why not have one or two of the old PIR sensors in the conservatory where a potential intruder can see them, but not wired? i.e. just a visual deterent. Then have your door sensors for real.

 

The further point is that if you make it a "new" installation the installer will be unambiguously responsible for its correct operation.

Edited February 7 by Geoff1946

[Larches 2]

7 hours ago, Geoff1946 said:

Why not have one or two of the old PIR sensors in the conservatory where a potential intruder can see them, but not wired? i.e. just a visual deterent. Then have your door sensors for real.

 

Now that's not a bad idea! Only issue I suppose is if anyone tried to enter via the roof hatch, as there is then no functioning PIR to catch them, but it's probably unlikely (pitched polycarbonate roof, would require access via neighbour's driveway and forcible entry) and then there's still an internal door to get through to access the rest of the house.

 

Also some useful info there regarding the sensors and how they age. I'm happier to cough up for replacements in that knowledge. Many thanks.

[Geoff1946 145]

I would forget locking internal doors. Any internal security, except a safe, would simply add to the damage  done once an intruder had gained entry.

The same applies to locking valuables in furniture, such as desks. A burglar will simply smash their way in.

In my opinion your greatest defence is in making your property appear too hard to attack, with visible alarm and cameras.  Most low-life will then just move on elsewhere.

 

This is of course just my opinion. I've heard others say that putting up an alarm box, etc,  makes it look like you have things worth pinching.  Take your pick!

 

[Larches 2]

I've often wondered about that last point. I got some Smartwater forensic liquid through work years ago, and it came with window stickers etc - should be a deterrent, but I sometimes think it's more of a statement saying 'hey look, we've got stuff worth nicking'. Ironically we don't really have a lot in the way of valuables, but having experienced the trauma of burglary before, I still want to do all I can to prevent a break-in. Aside from the property marking signs etc, I agree that it makes sense to have obvious security that will look plausible to others - it's one reason I've got new bell boxes on our list, replacing the blatantly old-looking things we have just now (it's not like they cost a lot anyway).