Where should Carbon Monoxide (CO) alarms be placed?

CO is invisible, silent and odourless and a very real threat. To ensure that homeowners or tenants remain safe, installers have a crucial role to play. This means ensuring that the right number of alarms have been installed and they have each been placed at both the correct position and height. At a minimum, a CO alarm should be installed on each level of the home - ideally on any level with fuel burning appliances and outside of sleeping areas


How many CO alarms per house?

The Building Regulations Approved Document J for England and Wales states that a CO alarm must be fitted “where a new or replacement fixed solid fuel appliance (e.g. wood and coal burning, not gas) is installed in a dwelling.”

For homes with sources of CO in many rooms, the regulations recommend that if installing an alarm in each room is not possible, then priority should be given to rooms containing flueless or open flued appliances that are used most frequently and rooms where occupants spend the most time.

In Northern Ireland, as part of the Building Regulations (Northern Ireland) 2012, it is mandatory for a CO alarm to be installed in all homes where a new fossil fuel appliance is installed.

Since 1 February 2022, all homes in Scotland must have a CO alarm in all rooms where there is a fixed combustion appliance. The significance here, is this law applies to all properties – private and rented, and is not limited only to new builds, or when any new solid or carbon fuel appliances are installed. Read our blog on the updates to the Scottish regulations here.


What are the regulations for landlords?

There are further requirements for landlords. In England, the government has updated the Smoke and Carbon Monoxide Alarm (England) Regulations 2015. Beginning in October 2022, CO alarms are now mandatory in rooms with a fixed combustion appliance (excluding gas cookers) in both rented homes (private rental and social). CO alarms are also mandatory with the installation of any heating appliance (excluding gas cookers) as per the Building Regulations.

In Wales, the Renting Homes (Wales) Act 2016 has been updated to ensure landlords provide CO alarms in their properties where there is any gas appliance, oil-fired combustion appliance, or solid fuel burning combustion appliance.

In Scotland, landlords must install CO alarms with sealed batteries which must last ‘for the duration of the product lifespan’, in any space where there is a solid or carbon‑fuelled appliance, such as a boiler, wood-burning fireplace or flue.

In all regions, landlords are required to repair or replace the CO alarm, as soon as their tenant has reported any faults or damage to the alarm.


Where on the wall or ceiling should alarms be placed?

Once you have identified which rooms to protect, the next step is to decide where to position and install the CO alarms. A study conducted by the Health and Safety Laboratory for the Health and Safety Executive 2011 found that out of 100 alarms tested, over 20% were not fitted correctly, mainly due to being at the wrong height or not close enough to the potential source of CO. To avoid this, the British Standard EN 50292 recommends that CO alarms are fitted:

  • In every room that contains a fuel burning appliance

  • At least 300 mm from any wall (for ceiling mounted alarms)

  • At least 150 mm from the ceiling, above the height of any door or window (ForWall mounted alarms)

  • Between 1 and 3 m (measured horizontally) from the potential source of CO

The British Standard also recommends that an alarm is not fitted:

  • In an enclosed space

  • Where it can be obstructed

  • Directly above a sink>

  • Next to a door, window, extractor fan, air vent or similar ventilation opening

  • Where the temperature may drop below –5 ºC or exceed 40 ºC.


Keeping a CO alarm in good working order

Alarms can only detect a problem after smoke or CO reach their sensors, which means you must place them in locations free of obstructions. It is also important that the alarm stays clean and protected from adverse environmental conditions to continue working for its intended life cycle, which is typically 7-10 years. To do this, inform householders and tenants that they should unplug the unit and follow the manufacturer’s instructions on how to clean or dust the device at least once a month. They should also test the carbon monoxide alarm by pressing the test/reset button once a week.

Click here to explore our range of carbon monoxide alarms.