Smoke Alarm Beeping – Why your smoke alarm is beeping Every 20 seconds

Follow me
Licensed Electrician at United Electrical Services
Licensed Electrician in Melbourne, Registered Electrical Contractor. Currently servicing Melbourne and surrounding suburbs I've been working actively in the electrical industry for 30 years and registered with Energy Safe Victoria.
Follow me

Smoke Alarm Beeping – Why your smoke alarm is beeping Every 20 seconds

Have you just got comfortable in bed and ready to fall asleep, then you here a BEEP or a CHIRP every 30 to 60 seconds, yes its your smoke alarm telling you there is an issue. Let’s not get confused between a beep or when your smoke detector sounds an alarm. There is a huge difference between the both and unless its a loud constant screeching noise then you will be safe for now. Please remember “Before using the alarm silence button or assuming there are no fires, identify that a source of smoke is not present and certain that safe conditions exist”.
Smoke Alarm changing a battery

Smoke Alarm changing a battery

The chirping or beeping some people my explain coming from your smoke alarm is letting you know there are a couple of conditions that you may have to deal with. This trouble shooting guide will help you determine the reason why your smoke alarm is beeping.

Firstly if your smoke alarm has been triggered into alarm by burning toast or cooking smells and then you push the hush button to disarm the detector, then after it stops alarming the smoke alarm will be going though a cycle to reset itself and will chirp for 5 minuets every 30 to 60 seconds.

All 240 volt smoke alarms have a battery back up. Smoke alarms are usually wired on different circuits in a property and you may have not noticed that 240 volt power has been interrupted on your smoke alarm. To be certain you will find a green LED light indicator that should constantly be on and not flashing at any time. If there is no green light inductor glowing then you have a power failure at the unit and the 9 DC volt battery is in use.

We can replace your smoke alarm batteries for all models
We can replace your smoke alarm batteries for all models

You will notice a second LED on your smoke alarm in Red, the red LED light indicates normal operating condition when it flashes once every 40 seconds. If the red LED inductor remains on at all times and dose not flash every 40 seconds then there is a problem with you smoke alarm as this indicates it is in alarm mode and there is no alarm noise from the detector.
If you smoke alarm is over 5 years old and has not had scheduled maintenance, dust buildup around the smoke alarm may also interfere with smoke alarm performance and reliability and possibly cause chirping.
Smoke alarms have a low battery indicator in them and when you battery is low an audible “chirp or beep”will occur every 30 to 40 seconds.
If you change your battery and chirping still exists, is the smoke alarm in “Hush Mode”? you may have pressed the hush button accidentally or the battery terminals are not be making contact properly and your smoke alarm will need to be services. Most good quality smoke alarms only allow you to insert the 9 volt DC battery one way so there is no mistake. Smoke alarm battery’s need to be replaced every year.
Make certain that the battery tag has been cleared and nothing obstructing the battery . Use only a new battery from an sealed package, and find instructions that show the right battery is used in the specification list in the manual.

Is your smoke alarm detector beeping
Is your smoke alarm battery operated only or mains powered

The interesting point that really confuses people with smoke alarms beeping is when they beep, you will notice that your smoke alarm will tend to beep more often during cooler temperature’s at night than during the day, most smoke alarms have been designed to do this since most people are home at night to alert them, than during the day.

If the tips above still have not resolved you smoke alarm beeping problem, it possible your smoke detector has retched its life’s span and will need to be replaced.Change your battery every year

Change your battery every year and test your smoke alarm


There are a number of smoke detectors available today so replacing a smoke alarm battery can be tricky. We have provided a video of a more common unit. Other brands and different maintenance technique include…..

  • Clipsal smoke alarms
  • Quell smoke alarms
  • PDL lithium rechargeable smoke alarms
  • Chubb smoke detectors
  • HPM Legrand
  • Homeguard Smoke Alarm
  • PSA Smoke Detector Alarm
  • Exelgard Smoke Alarm
  • Brooks smoke detectors

Most come in a variety of either photoelectric or ionization models

United Electrical Services provide a reliable smoke alarm maintenance program to suit your budget needs and are happy to answer any questions you have about your smoke alarm, or if you simply would like to book an appointment you can contact us on 03 8361 5889 or email us at