FAQ | Carbon Monoxide Alarms

What is carbon monoxide? 

Carbon monoxide gas, also known as CO, is a silent killer and is a highly poisonous gas that has no colour, taste or smell. It is invisible to the human senses. Carbon monoxide is produced when a fuel is not burnt properly. The most common sources are faulty boilers, gas fires and cookers.


Where should I install Carbon Monoxide alarms in my home? 

Please watch this video to learn more




Positioning Carbon Monoxide alarms correctly throughout your home is vital to ensure they provide the maximum detection and respond as quickly as possible in the event of a Carbon Monoxide leak.

Ideally, an alarm should be installed in every room containing a fuel-burning appliance and every sleeping room. CO alarms should also be installed in any room which a flue passes through, even if the flue is fully enclosed or concealed.

When positioning Carbon Monoxide alarms, it is important to note that there are different requirements depending upon if the alarm is being installed in a room with a fuel-burning appliance or not.


In a room with the fuel burning appliance:

  • Alarms should be positioned on the ceiling
  • Should be fitted between 1m–3m from potential sources of Carbon Monoxide. Figure A
  • Positioned at least 30cm from walls, light fittings, or any obstructions. This is to ensure that they are outside of any ‘dead air’ spaces that occur in corners that can affect the performance of your alarm. Figure B
  • If the fuel burning appliance is in a confined space for example, a boiler room, then the alarm should be positioned on the ceiling just outside the room.
  • Peaked and sloped ceilings – carbon monoxide alarms should be positioned a maximum of 60cm vertically down from the apex. Figure C
  • If wall mounted and manufacturers guide advises wall mounting - position close to the ceiling but at least 15cm down, at least 30cm from a perpendicular wall and between 1m–3m from the fuel-burning appliance. Figure D


In a room without a fuel burning appliance:

  • Alarms should be positioned at breathing height. Figure E
  • In a bedroom, this could be at the height of the bedhead. Figure F


  • Position in enclosed or obstructed space. 
  • Directly above a cooking or heating appliance.
  • Directly above a sink.
  • Next to doors, windows, extractor fans or vents.
  • In an area were the temperature exceeds -10o to +40o Celsius.
  • Dirty and dusty environment 

Figure A 

 Siting Carbon Monoxide Alarm

Figure B 

Siting Carbon Monoxide Alarm on Ceiling

Figure C

Siting Carbon Monoxide Alarm on Sloped Ceiling

Figure D

Siting Carbon Monoxide Alarm | Wall Mounted

Figure E

Siting Carbon Monoxide Alarm | Breathing Height

Figure F

Siting Carbon Monoxide Alarm | Sleeping Height