Posted on May 29, 2025
Carbon Monoxide - Business
Carbon monoxide can be given off by any appliance which burns a fossil fuel such as gas, coal or oil. It can enter your home if your appliance is faulty, or the room is not properly ventilated, or the chimney or flue is blocked.
Carbon Monoxide alarms can make a very effective contribution to secure the safety of you and your family. However, there are some points you need to be aware of to use these alarms effectively.
What type should I use?
Many different alarms are available but we recommend that the alarm you buy should comply with EN 50291, and this should be marked on the box. We recommend that it also carries the Kitemark from BSI (or an equivalent), who test and certify that it does conform to EN 50291. Also, we only recommend those alarms that have an "end-of-life" indicator - this is an option that only some alarms offer. This indicator should not be confused with any "fault" indicator.
You MUST test the alarm regularly and replace it when it reaches the end of its life.
This is extremely important. The one disadvantage of Carbon Monoxide alarms is that they can provide a false sense of security - they have a limited lifetime, and the manufacturer will specify when it should be replaced. Because this can be five or more years away, it will be extremely difficult to remember to do this, which is why we only recommend those units that incorporate an end-of-life indicator. One such Carbon Monoxide alarm that complies with these requirements is the Honeywell SF450EN alarm.
While the risk of a false sense of security arises with any alarm that is not working correctly or is not installed in a suitable location, it is a particular risk with Carbon Monoxide detectors: a smoke detector acts as an additional warning of the presence of smoke (because you can also see and smell smoke), but because Carbon Monoxide symptoms are not so clear-cut, there is a greater tendency to rely on a Carbon Monoxide alarm. The risk is that you will ignore some symptoms or signs of Carbon Monoxide if the alarm does not go off - this trust will be misplaced if the alarm has reached the end of its life or is not correctly located, which is why we only recommend alarms that have an end-of-life indicator.
One alarm may not be sufficient
If all your fuel-burning appliances (including their exhaust flues and air supplies) are in the one room, then one detector in that room may suffice. If they are located in more than one room, then an alarm should be fitted in each room. However, if those alarm(s) cannot be heard in any living rooms and in all the bedrooms, more advanced alarms that include the provision for interconnecting them can be used. If one of a set of interconnected alarms detects CO, it will trigger the other units to also sound an alarm, allowing you position extra ones close to the living rooms and bedrooms, where they will be audible.
An alternative strategy, particularly more suited where the appliances and/or flues are spread across too many rooms, is to locate the alarms in the living rooms and bedrooms. In this situation, note that the manufacturers usually recommend installing the alarms at breathing height rather than at high level.
Where can I get one?
Carbon Monoxide alarms are available from many heating equipment suppliers, hardware stores, DIY outlets, etc. You can also obtain an alarm from many main gas suppliers.
Buy a carbon monoxide alarm now
Do not use a Carbon Monoxide alarm as a substitute for the proper installation and servicing of appliances, vents and flues. Always follow the alarm manufacturer's instructions and if any aspects are unclear, contact them directly for further guidance.
Find out more
Carbon monoxide sometimes makes people feel ill. If you develop any of the following:
- drowsiness
- headaches
- chest pains
- sudden giddiness when standing up
- sickness
- diarrhoea
- stomach pains
Stop using your appliances and ask your doctor to check for carbon monoxide poisoning.
For further information, call the Carbon Monoxide Information Line on 1800 898 989
Sooty stains on or just above appliances. Appliances that burn slowly, badly (floppy flames), or go out. Condensation or dampness on walls in the room once the appliance is lit.
- Ensure your appliances are correctly installed and regularly serviced.
- Ensure the rooms in your home containing appliances are properly ventilated - never block vents.
- Make sure all chimneys and flues are regularly swept and kept clear.
- Carbon Monoxide detectors / alarms are available in all good hardware stores. These provide an extra safety precaution, but never rely entirely on them. If you have a problem contact your fuel supplier.