Most common causes

  • Flat or low backup battery: the number-one cause, even in mains-powered alarms.
  • End of life: an expired 10-year alarm chirps regardless of the battery.
  • Dust or insects in the sensor chamber cause intermittent chirps and false alarms.
  • A loose battery: the drawer isn't clicked fully home.

Chirps often start at night, when cooler temperatures drop battery voltage enough to trip the warning.

Try this first

  1. 01Identify which alarm is chirping: in an interconnected system, only the faulty unit chirps.
  2. 02If replaceable, fit a fresh battery and close the drawer until it clicks.
  3. 03Gently vacuum around the alarm to clear dust and insects.
  4. 04Check the manufacture date on the back: near or past 10 years, it's due for replacement.

When to call an electrician

Chirping after a fresh battery, a sealed 10-year alarm, or you'd rather not chase it up a ladder: that's our cue. We'll find the real cause and fix it. Don't just pull the battery and leave it: that leaves you unprotected, and in a rental breaches the tenant's duty not to disable alarms.