Why Is My Carbon Monoxide Alarm Going Off & How Do I Stop It?

Jan 7, 2020 | Home Security

“Why is my carbon monoxide alarm going off?” is one of the most frequently asked questions in Google about CO detectors.

Lots of people are going onto Google to research whether the sound from their carbon monoxide alarm is indeed a warning or just a false alarm.

And lots more are just removing the batteries to stop the noise!


As soon as you take those batteries out, your device stops protecting you from CO2.

And you are vulnerable.

Your monitor is beeping for a reason.

Why Is My Carbon Monoxide Alarm Going Off?

Here are four possible causes:

  1. It detects CO pollution in the air and you need to get out of the house
  2. The batteries need changing
  3. It is a false alarm caused by other household items
  4. The detector is malfunctioning

Let’s look at each bullet point in more depth to help you resolve the unwanted beeping. After all, you don’t want your carbon monoxide alarm going off for no reason!

carbon monoxide alarm going off

There is CO pollution in the air

Naturally, the first conclusion you would jump to when your carbon monoxide alarm is going off is that it can detect traces of CO in the atmosphere.

CO is getting into your home somehow. Whether it’s from your own house or a neighbour’s house. Jump to the bottom of his blog post for what to do if your carbon monoxide detector is bleeping.

In most cases, your alarm will only be triggered if a fuel burning appliance has not been regularly serviced by a professional with a Gas Safe accreditation, and is running inefficiently. It is vital to get your appliances serviced regularly.

BUT it could also be:

The batteries need changing

For some models of carbon monoxide detectors, you can replace the batteries. In others, you have to replace the whole unit. It is advisable to change the batteries every year – whether the alarm is beeping or not.

Your carbon monoxide detector is giving out false alarms from other appliances

In domestic properties, your CO alarm can be triggered by any fuel burning appliance. Think boilers or gas hobs and ovens. All of these appliances give off small traces of CO and it’s not usually a problem. But the levels can rise without adequate ventilation. Either the vents have been blocked by dust or were never there in the first place.

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Your carbon monoxide detector is malfunctioning

Always check before you buy that your detector has approval to BS EN 50291-1: 2010.

If you have bought a cheap, stand-alone CO detector online, the internet reveals that these can be sensitive to Hydrogen gas and even large quantities of petrol fumes.

But unless you study the manual carefully, it is hard to work out whether the beeper indicates a real alarm or a false one. The best advice is always to follow the steps listed below just to be on the safe side.

What to do if your carbon monoxide alarm is going off

To reduce the risk of CO poisoning, which can be deadly if you are exposed for long periods, follow these instructions:

  • Turn off all fuel-burning appliances: cookers, central heating boilers, gas fires, etc
  • Immediately get fresh air into the property by opening all doors and windows
  • Call a qualified technician to find the route of the problem and address it before using that appliance again
  • Check for carbon monoxide poisoning symptoms like dizziness, vomiting and headaches. Call the fire brigade and immediately move to a location with fresh air
  • Do not re-enter the property until it has been thoroughly aired out and the appliances have been checked and fixed by a professional

Seems like stand alone CO alarms can be a bit unreliable…

So, if you don’t want to be Googling “Why is my carbon monoxide alarm beeping” in the middle of the night, it is worth considering other options.

Many home security companies will include a carbon monoxide alarm with your regular burglar alarm system. It’s definitely worth asking them the question when you take control of your home security.

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