If a fuel burning appliances is installed within a boiler room or cupboard, an area not normally used, it is recommended that the alarm be installed just outside of this location to allow the alarm to be heard if activated.
The alarm should be installed within 1m and 3m from the appliance when installed within the appliances room.
The alarm should be installed as close to or fixed to the ceiling and if mounted on the wall, as high as possible.
If fitted to the ceiling, the alarm needs to be at least 300mm from any lighting and wall sockets.
Where installed in rooms without fuel burning appliances, the carbon monoxide alarm should be installed at breathing height. So in bedrooms this may be lower than head height.