Union Jack Flag. NoEntry by Sonis is designed and manufactured in Dunfermline, UK.

Designed and manufactured in Dunfermline, UK

What Causes False Alarms in Your Security System

Traditional security is measured in the number of sensors spread across your home.  One of the main concerns using sensor-based traditional alarms is the number of false alarms

False Alarm (also known as) a Nuisance Alarm via PIRS

1. The first cause of PIR false alarms is a low unstable voltage at the detector. Test to make sure the voltage at each PIR is above 13 VDC and stable.

2. The second cause of false alarms is sudden infrared movement heat changes in view of the detector.  Check behind and inside the PIR for insects and identify objects that can move or rapidly change temperature (e.g. pets, vermin radiator or boiler etc.).  You can adjust the sensitivity of some standard motion sensors, which means more movement is required to sound an alarm but they still cannot tell the difference between a person walking around and a four-legged friend.  This can lead to frequent false alarms.

3. The third cause of false alarms is white light momentarily blinding the detector.

4. The fourth cause of false alarms is a direct draught striking the detector.

This causes air convection inside the PIR.  Make sure the cable and secret holes are totally sealed and don’t forget the hole where the cable comes through the cavity wall or ceiling.

5 The fifth cause of false alarms is RF/EMI signals.  A mobile phone can be used to test susceptibility to RFI by placing the aerial against the PIR casing and transmitting. Fit an ACT 1376 stabiliser inside the PIR to eliminate RFI.


NoEntry by Sonis – the World’s first plug and play, self-installing, all-in-one Intruder alarm which eliminates the need for PIR motion, door and window sensors with pet-friendly intelligence, detects intruders, not pets.  

Other Factors Contributing to False Alarms 

Human Error

This is usually due to the homeowner setting off the alarm by mistake, then forgetting the code or taking too long to enter the code. False alarms are also often caused by guests in your home, including cleaners, tradesmen or babysitters who have not been informed about how to turn off the alarm

Poorly designed security systems

House alarms are more susceptible to false alarms if the installer did not consider the home, who lives in the home and how you use the home.  Bad wiring and incorrectly placed sensors can also cause false alarms.  

Unlocked or loose doors and windows

Door and window sensors are activated when the connection between the two sensors is disrupted. If a door or window is loose, it can easily be rattled by the wind and trigger an alarm. 

Lack of Maintenance/ Upkeep.

Although security system equipment generally does not need much maintenance, it does require some.  A faulty sensor can develop faults and either not detect when they are supposed to or if faulty they can also cause false alarms as they detect intrusions even when there are none.  Correct installation and regular maintenance can prevent issues with your sensors.

Otherwise,  low batteries or inconsistent power source: Most wireless home security systems contain batteries that occasionally need to be changed and replaced.  These system components typically give audible warnings that the battery levels are low but in some cases, a low battery can trigger a false alarm.

Outdated or old security equipment

If it’s been a while since your security system was installed, false alarms may occur. 

Your equipment may need to be replaced. 

Curtains and other movable objects

Be sure ceiling fans are turned off and there are no hanging banners or balloons in any area where a motion sensor is located.  Close and lock all doors and windows: a breeze Can move the curtains and plants causing a false alarm


NoEntry by Sonis has achieved the ability to protect a whole house from one single and attractive device helping to reduce false alarming in domestic properties.  

Police Response 

If you have a monitored alarm system with Police response, it’s not just the installer, maintainer and monitoring company’s responsibility to filter out false alarms, it is yours too.  If you have too many false alarms, your Police response could be taken away! Any activations without apparent damage or entry to the property, and line faults, are counted as false alarms – unless proven otherwise.

The police work on a ‘3 strikes and you are out’ system.  If you experience a false alarm three times within 1 month, you are downgraded and the Police will not treat your alarm going off as a priority.