Why does my home alarm keep going off when nobody is there?

First make sure it is safe

‘False alarm’ is a conclusion, not a safe starting assumption. If you are away and receive an alarm notification, or arrive to find signs of entry, do not enter the property to investigate. Follow the response plan agreed with your monitoring provider. If there is an immediate threat to life or property, call Triple Zero (000).

If you are safely inside and know the activation was accidental, disarm the system in the normal way. A monitored customer should follow the control room’s instructions and be ready to use the agreed voice code. Do not give that code, an alarm PIN or access details to anyone who is not authorised.

Official source: Victoria Police: report an incident or crime(opens in a new tab)

Save the clues before they disappear

The panel normally knows more than the siren alone can tell you. Before clearing messages or arming the system again, record the details that can help identify what happened.

• The date and exact time of the activation.
• The zone number or room name shown on the keypad or app.
• Every word, light or symbol shown on the keypad.
• Whether the siren sounded or the keypad only beeped.
• Whether the monitoring centre called and which event it received.
• Whether power, NBN service or mobile coverage changed at the time.
• Anything different near the affected detector, door or window.

Official source: Ness D8X/D16X Deluxe User Manual(opens in a new tab)

The cause may be in the room, the equipment or the way it was used

Queensland Police lists pets and pests, power or telecommunications failure, storms, moving objects, draughts, user error and equipment or maintenance problems among the possible causes of unwanted alarm activations. Those are categories to investigate, not proof of the cause at a particular property.

Useful observations include a new heater or fan, curtains or decorations moving through a detector’s view, pest activity, building work, a changed pet routine or a room that has become unusually hot, cold or humid. Note what changed and let the event history and testing guide the diagnosis.

Official source: Queensland Police: electronic security alarm systems(opens in a new tab)

A motion detector reacts to its environment

A passive infrared detector, often shortened to PIR, looks for changes in infrared energy across its detection pattern. It does not understand the room as a person does, so placement, surroundings and configuration all matter.

Ness guidance says indoor PIRs should be kept away from direct sunlight, heating and cooling sources and high humidity that may cause condensation. It also tells installers to seal oversized cable and mounting openings to help keep dirt and insects out. Pet-aware operation requires the correct detector, position and settings; it is not a promise that every animal or room will be ignored.

Official source: Ness LUX hardwired PIR Installation Manual(opens in a new tab)

Doors, windows, cabling and wireless devices need separate checks

An opening sensor relies on the relationship between the sensor and its magnet. Movement in a door, window, frame or mounting can matter even when the opening looks closed. For a wireless device, battery condition, signal path, mounting surface and the surrounding environment can also affect reliable operation.

On a wired system, the detector is only one part of the zone. The cable, joins, terminals, tamper circuit and panel input can all need testing. NorthTech runs cable wherever possible and tests existing cable before deciding whether it should stay. Changing a detector without proving the fault can leave the original problem in place.

Official source: Ness 6020 Door and Window Sensor Manual(opens in a new tab)

A beep or fault message may not be an intrusion alarm

People often describe any noise from the keypad as the alarm ‘going off’, but a warning beep can report a different condition from an intrusion siren. Depending on the installed system, the panel may be drawing attention to mains power, its backup battery, a wireless-device battery, a communication path, tamper protection or supervision of a connected device.

Write down the message before acknowledging it. Do not assume that replacing the first battery you can see will resolve it, and do not open detectors, the control panel or a siren. Those housings can have tamper protection and contain powered parts. Internal checks belong with an appropriately licensed security-equipment technician.

Official source: Victoria Police: private security licence activities(opens in a new tab)

Do not solve a repeated activation by removing protection

Some alarm panels allow a zone to be excluded or bypassed. That means the panel ignores that zone, so it is not a repair. Ness describes bypass as a temporary measure while a false-activating detector awaits service and notes that monitored customers may need to advise the control room.

NorthTech should identify the cause before an affected zone is returned to normal use. The service may include reviewing the panel memory, checking detector placement and condition, testing cabling or wireless communication, confirming battery and power conditions, and reproducing the fault where possible.

The aim is not merely to stop a noise. It is to restore confidence that every protected room, door and window will respond when it should — and remain stable when it should not.

Official source: Ness: monitoring alarm definitions and responses(opens in a new tab)

What to send with a Support Request

Include the panel or keypad brand and model if known, a clear photo of the display, the event time, the affected zone, whether the alarm was fully armed or in a home mode, and whether monitoring contacted anyone. Mention any recent electrical work, renovation, cleaning, pest activity, heating or cooling change, new pet or movement of furniture near the detector.

Do not send your user code, monitoring voice code or a photograph that reveals an address, alarm PIN, floor plan or the location of every security device.

• NorthTech alarm systemsUnderstand zones, detector choices and NorthTech’s wired-first design approach.
• Alarm monitoringSee how a monitored response differs from the local siren and app notification.
• Power and NBN outagesCheck which parts of a security system can keep working during an outage.