Most intruder alarm activations are not intruders. They are doors left ajar, staff who forgot the code, spiders on detectors and batteries running down. Each one means a call-out, a disturbed night for whoever is on the key holder list, and possibly a charge from your alarm or security company.

There is a bigger cost too. Under the Garda policy on monitored intruder alarms, three false alarms in a three-month period can lead to Garda response being withdrawn from the system until the problem has been fixed. That is the last thing you want on the night there is a real break-in.

Find out what is causing them

Ask your alarm company or monitoring centre for the activation log for the last few months. For each activation it shows the time and which zone or detector triggered. Patterns stand out quickly: the same detector every few nights, activations just after closing time, or alarms during storms.

The usual causes, and the fixes

1. Doors and windows not fully closed

A door that is pulled to but not latched can move in the wind and trigger its contact. Fix closers and latches, and make "check every door" part of the closing routine.

2. User error at opening and closing

The most common cause of all. Staff who are unsure of the code, the set-up time or the order of doors will set the alarm off. Keep the number of people with codes small, give each person their own code, train them properly and put a simple instruction card beside the panel.

3. Movement inside the building

Balloons, hanging signs, curtains moved by heaters, insects on detectors and stock that falls after hours can all trigger movement detectors. Keep the area in front of detectors clear and ask your installer whether a detector is badly positioned.

4. Faulty or ageing equipment

Detectors, contacts and batteries wear out. Make sure the system is serviced at the intervals your installer recommends, and replace parts that keep causing problems rather than just resetting them.

5. Work in the building

Cleaners, contractors and engineers who arrive early or stay late regularly set alarms off. Tell your monitoring centre before any planned work, and give contractors the right instructions or have somebody let them in.

6. Weather and power

Storms, power cuts and lightning can cause activations, especially on older systems. A healthy standby battery and a well-maintained system cope much better.

Make sure somebody always attends

The Garda policy also expects a key holder to attend after a verified activation, and a key holder who fails to turn up counts against the system in the same way as a false alarm. Keep your key holder list current, or use a key holding service so that a licensed officer always attends. Our article on what happens when your alarm goes off explains the process.

Learn from every activation

After each call-out, find out what caused it and fix that cause. When our officers attend an activation through our alarm response service, the report you receive includes what they found, so faulty detectors and doors are dealt with before they cause the next one.

A five-minute monthly check

  • How many activations were there last month, and what caused each one?
  • Is any detector or zone appearing again and again?
  • Is the key holder list up to date?
  • Do all staff with codes still work for you?
  • When is the next service due?

If false alarms are disturbing your nights, talk to us about key holding and alarm response for your premises.