Why does my smoke alarm keep chirping or beeping

So why does my smoke alarm keep “chirping” or beeping??

The simple and thankfully most common answer is that your smoke alarm will chirp at regular intervals when the battery is weak and needs to be replaced.  Once the battery is replaced, the beeping or chirping should stop.  NOTE: most manufacturers do not recommend using rechargeable batteries in the alarms. If the unit continues to chirps or beep at random intervals after replacing the battery, check for the following: 

1) The battery may not be properly installed.

Make sure the replacement battery is new and within use date, and that it is snapped onto the connectors properly and securely.  

2) The smoke alarm cover or unit may be contaminated or dirty.

Many alarms have built in insect/dust screens but items can collect in the sensing chamber of the alarm. An accumulation in the sensing chamber can cause the unit to chirp. It is good practice to clean the smoke alarm when you change the battery.

 3) An electrical fault- more uncommon.

For alarms that are hard wired i.e. powered direct from the mains, alterations in the electricity supply can cause units to function incorrectly.  Alterations could be due to faulty wiring or earthing, uneven supply etc.  This type of fault would need investigation by a suitably qualified electrician

4) You have an alarm with a silence mode

Some smoke alarms have a silence feature which can temporarily quiet an unwanted alarm for a given period, often upto 10 minutes maximum. During this period the unit isn't disabled but it is made temporarily less sensitive to smoke.  

When in this “silent” mode the alarm may well chirp or beep as a constant reminder to you to ensure you reset it back to its proper function.


REMEMBER Smoke alarms shouldn't be switched off or disconnected. If they sound too frequently you should relocate the alarm.