Do I need a carbon monoxide alarm?

Protect your family with a CO alarm in your home.

Why your home may need a carbon monoxide alarm

Carbon monoxide is an invisible and very dangerous gas that can cause serious illness, brain damage and death.

Detecting CO

You can't see, smell or taste carbon monoxide so it's very hard to detect without a CO alarm.


Symptoms of CO poisoning include headaches, nausea and vomiting, and in extreme cases, blackouts and convulsions.

Learn more about symptoms


CO poisoning causes around 40 deaths and 200 hospitalizations a year in the UK alone, according to the National Institute for Health and Care Excellence (NICE).

Possible sources of carbon monoxide leaks around your home

Worried about a CO leak? Call the National Gas Service on 0800 111 999 and read our tips on what to do if you suspect a leak.

Your gas boiler

The flame on your boiler should
always burn blue. If it's yellow or
orange, it could mean that you've
got a carbon monoxide leak.

Your gas fire

Has your gas fire become difficult to light lately? It might be because too much carbon monoxide is being produced.

Your cooker

Sooty stains on your cooker — or other fuel burning appliance — might be a sign that they’re not working properly and are leaking CO.

Protect your home from carbon monoxide (CO)

An alarm gives you an early warning about any carbon monoxide leaks in your home before they get to a dangerous level.

  • Accurately detects low levels of CO in your home
  • Easy to set up, maintenance free and self-testing
  • The alarm is really loud, so it’s easy for the average person to hear
  • Five year battery life and manufacturer guarantee

How to set up your carbon monoxide alarm

Step one

Get it out of the box.

Step two

Remove the tag to activate the battery.

Step three

Put it somewhere high up, near a gas or fossil burning appliance.

Learn more about where to put it

Need to know more?

Why should I have a CO alarm?

Our alarms are made specially for British Gas by the UK leading manufacturer Fire Angel, who are endorsed by the UK Fire Service. The alarm has an advanced electro-chemical sensor that accurately detects low levels of CO in the air – before it becomes harmful. You can test it yourself, so you can check it's working from time to time. The alarm is really loud – at 85 decibels, it’s about as loud as an old-fashioned alarm clock - so it’s easy for the average person to hear. Our alarm is guaranteed by the manufacturer for five years – which is how long the battery should last. It’s easy to set up and doesn’t need any maintenance.

What happens if the alarm stops working before the five years are up?

If it stops working, contact the manufacturer Fire Angel, they will be able to help you.

Fire Angel support can be contacted on:
0330 094 5830 / 02477 717700

How many do I need?

It's a good idea to have an alarm in every room where you have a fuel burning appliance, including any room that has a flue running through it and in every sleeping room. Fuel burning appliances include gas boilers, cookers and fire stoves. Visit Project SHOUT and our Gas Safety page for more information about how to protect yourself from carbon monoxide poisoning.

Where should I put my carbon monoxide alarm?

Your CO alarms should be placed up high, between one and three metres from the gas or fossil fuel appliance you're monitoring for CO leaks. They can be left free standing on a shelf or fixed to a wall using the sticky patches provided. If on a ceiling, the alarm should be mounted at least 30cm from any wall. If on a wall, the alarm should be mounted at least 15cm from the ceiling.

What if I'm having trouble setting up my alarm?

If you need help setting up your alarm call us on 0800 077 4472. The number is free to call.

How loud is it?

It's very loud! The alarm is 85 decibels - which is about as loud as an old-fashioned alarm clock, so it should be easy enough for the average person to hear.

Is it portable?

Yes. Since it’s small and battery operated, you can even take it with you to your camping trips – in fact, a surprising number of carbon monoxide incidents happen on camping trips.

When do I need to replace my alarm?

We recommend replacing your alarm when you need to change your battery – which is about every five years.

What are the potential sources of carbon monoxide poisoning?

Common sources of carbon monoxide poisoning will come from your:

  • Boiler
  • Fireplace
  • Cooker

However, carbon monoxide poisoning can come from any fuel-burning appliance such as:

  • Oil and gas boilers
  • Portable generators
  • Oil or solid fuel cookers
  • Gas or paraffin heaters
  • Barbeques
  • Clogged chimneys
  • Wood or gas fireplaces
  • Cigarette smoke
  • Any fossil fuel-burning appliance

What are the symptoms of carbon monoxide poisoning?

Symptoms of mild carbon monoxide poisoning include: slight headache, nausea, vomiting, fatigue. Symptoms of medium carbon monoxide poisoning include: severe headache, drowsiness, confusion and fast heart rate. Symptoms of extreme carbon monoxide poisoning include: unconsciousness, convulsions, cardiorespiratory failure, death. Feeling immediately better after leaving your house is another sign that you may be experiencing carbon monoxide poisoning.

What to do in an event of a CO incident?

Open all your doors and windows. Stop using all fuel-burning appliances and if possible, turn them off. Evacuate the building and leave all your doors and windows open. Call the National Gas Service on 0800 111 999. Get medical help for anyone you think might have carbon monoxide poisoning. Don't go back inside until the carbon monoxide alarm has stopped or you are told it's safe by an expert. Don't use the leaking appliance again until it's been checked by an expert.

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Additional information

  1. Monday to Saturday: 8am - 6pm, Sunday: Closed. We may record calls to help improve our service to you. Calls to 0330/0333 numbers will cost you no more than 01 or 02 numbers from landlines and mobiles. If you get 'inclusive minutes' with your package, calls to 0330/0333 numbers will be part of these.