Here is the short answer: pets and burglar alarms coexist fine when three things are right — detectors designed to tolerate animals, mounted at the height the manual states, aimed across the room rather than at the floor, sofa or stairs. Pet-immune PIRs are rated by weight (a common figure is up to 20kg), photo-verified detectors let you check what actually triggered, and placement does more work than any specification. Get those three right and the dog sleeps, the alarm sets, and 3am stays quiet.
In brief:
- Standard PIRs see a warm moving body; a labrador and a burglar look similar from the wrong angle. Pet-immune designs and correct mounting separate them.
- Weight ratings matter but placement matters more: keep furniture, radiators and stair views out of the detection field.
- Photo verification is the pet-owner's best friend — the alert arrives with pictures, so "was that the cat?" takes five seconds to answer.
The commonest reason a family alarm goes unset is four-legged: after the second false alarm blamed on the dog, the system quietly stops being armed — and an unset alarm protects nothing. It does not have to be that way, and it has not for years. Villa Road since 1975; here is how pet households do it properly.
Why do pets trigger burglar alarms?
A PIR detects moving body heat across zones in its view. A cat on a bookcase or a dog bounding up the stairs presents heat moving through multiple zones — which is exactly the signature the detector exists to catch. The fixes work on both ends: detector designs that discriminate (pet-immunity by weight, dual-technology confirmation, camera verification), and placement that keeps normal pet life out of the field. The physics is in PIR sensors explained; the practice is below.
What should a pet household buy?
Explicit pet-immunity, stated on the box: the Pyronix KX10DP-WE is a wireless dual-technology PIR rated pet-immune up to 20kg with a 10-metre range — the straightforward answer for a Pyronix household with cats or a mid-size dog. Remember the hard rule: detectors enrol only on their own manufacturer's panel, so match the detector to the system you run.
For Ajax households, verification changes the game: the Superior MotionCam HD sends photos with every alert — so on the rare occasion something does trigger, you see the cat mid-leap rather than lying awake wondering. Ajax detectors also carry adjustable sensitivity in the app, and Ajax's detector range is built for discriminating real intrusion from household life; start from an Ajax kit and add MotionCam HDs on the rooms the pets own.
Trade tip: night mode is the pet household's secret weapon — arm the perimeter (door and window contacts, and outdoor detection from our perimeter guide) while leaving interior PIRs off overnight. The house is protected at its shell, and the cat can hold the 2am grand prix undisturbed.
Where do the detectors go in a pet home?
- Mount at the stated height, dead level. Pet immunity is engineered around a mounting height — fit high or tilted and the geometry that ignores the dog stops working.
- Aim across open floor, not at climbing furniture. Bookcases, sofa backs, windowsills and cat trees put a small pet at burglar height. Keep them out of the field.
- Never face the stairs. A dog ascending is a rising heat source crossing every zone — the classic false alarm. Cover the hallway instead of the flight.
- Keep radiators and sunny glass out of frame. Heat sources amplify everything else.
- Contacts over PIRs where pets rule. In the room that belongs to the animals, protect the openings rather than the volume.
Pet-Friendly Alarms, Summarised
| Situation | Answer | WME pick |
|---|---|---|
| Cats / dog under 20kg, Pyronix system | Weight-rated pet-immune dual-tech PIR | Pyronix KX10DP-WE |
| Ajax system, any pet | Photo-verified detection + app sensitivity | Superior MotionCam HD |
| Large or many pets | Night mode: shell protection, interior PIRs off overnight | Ajax KIT2 S + contacts |
Expert Help in the West Midlands
Villa Road, Birmingham, since 1975. Tell us the animals — species, size, where they roam at night — and the system you run, and we will spec detectors and placement that hold. Half the pet-alarm problems that reach the counter are solved by moving one detector a metre; we would rather tell you that than sell you a box.
Browse burglar and intruder alarms and the Ajax range. Get in touch for a spec.
Related reading: house alarm keeps going off? and PIR sensors explained.
Frequently Asked Questions
Can you have a burglar alarm with pets?
Yes — with pet-tolerant detectors mounted at their stated height, aimed across open floor rather than at stairs and climbing furniture, and ideally photo verification so any trigger is checked in seconds. Night mode protecting just the shell of the house covers the rest.
What does pet-immune up to 20kg mean?
The detector's geometry and processing are designed to disregard animals up to roughly that weight moving at floor level, while still catching a person. The rating assumes correct mounting height — fitted wrong, the immunity goes with it.
Do cats set off pet-friendly alarms?
On the floor, rarely; at height, sometimes — a cat on a bookcase presents like something much bigger. Placement that keeps climbing routes out of the detection field matters more for cats than any weight rating.