What Actually Causes False Alarms — and How to Stop Paying for Them

Motion detectors aimed at moving air

Passive infrared sensors respond to moving heat. Point one at an HVAC diffuser, a space heater or a sunlit window and it will trip on schedule, usually in the middle of the night when the system finally cycles.

Re-aiming, masking or swapping to a dual-technology sensor solves nearly all of these.

Doors that no longer close the way they used to

Buildings settle. A contact gap of a quarter inch becomes half an inch and the zone faults every time a truck passes. Contacts are cheap; nuisance trips are not.

People, codes and pets

Cleaning crews, seasonal staff and shared codes cause more dispatches than equipment does. Individual user codes with schedules tell you who disarmed the system and when, which usually ends the problem on its own.

For homes with animals, pet-immune sensors rated to the correct weight belong in the plan from day one, not after the first fine.