Carbon Monoxide the Silent Killer in your Home

What is it?


Carbon monoxide (CO) is a colourless, odourless, tasteless, poisonous gas produced by incomplete burning of carbon-based fuels, including gas, oil, wood and coal. Carbon-based fuels are safe to use, however it is only when the fuel does not burn properly that excess CO is produced, which is poisonous.  When CO enters the body, it prevents the blood from bringing oxygen to cells, tissues, and organs.

You can't see it, taste it or smell it but CO can kill quickly without warning. According to the HSE statistics every year around 15 people die from CO poisoning caused by gas appliances and flues that have not been properly installed, maintained or that are poorly ventilated. Levels that do not kill can cause serious harm to health if breathed in over a long period. In extreme cases paralysis and brain damage can be caused as a result of prolonged exposure to CO. Increasing public understanding of the risks of CO poisoning and taking sensible precautions could dramatically reduce this risk.

There are signs that you can look out for which indicate incomplete combustion is occurring and may result in the production of CO;

  • Yellow or orange rather than blue flames (except fuel effect fires or flueless appliances which display this colour flame)
  • Soot or yellow/brown staining around or on appliances
  • Discolouration on walls and ceilings in the room
  • Pilot lights that frequently blow out
  • Increased condensation on windows

Keep Yourselves Safe


There are a number of simple steps that gas consumers can take to keep themselves safe.

Carbon Monoxide can be produced by any combustion appliance, including those that burn fossil fuels e.g. oil, wood and coal. 

  • If you have one of these appliances you should make sure that it is serviced and maintained by a competent person and the chimney is regularly swept.
  • Also, the purchase of an audible type Carbon Monoxide Alarm is essential for all households, they are not very expensive, but can be a life saver.

Early symptoms of carbon monoxide (CO) poisoning can mimic many common ailments and may easily be confused with food poisoning, viral infections, flu or simple tiredness. Symptoms to look out for include:

  • headaches or dizziness
  • breathlessness
  • nausea
  • loss of consciousness
  • tiredness
  • pains in the chest or stomach
  • erratic behaviour
  • visual problems

For more information visit the NHS  or telephone NHS Direct on 0845 4647.

If you or your family experience any of the above symptoms and believe you may have been exposed to carbon monoxide, you should seek urgent medical advice from either your GP or an A&E department. 

Some carbon monoxide alarms we recommend here at gasboilerforums are;







These are all electronic models, with a loud audible alarm in case of a problem. They also carry a very good operational life and good warranty.

You can get small paper spot indicators that change colour in case of a problem, however you may not be aware that the colour spot has changed and therefore will not be aware of a problem. This is the downside compared to an electronic audible version. They only have a short operational life of typically six months, and you have to be organised to remember to renew them.

If you live in a flat or apartment and your neighbours around you use gas appliances, a carbon monoxide alarm is essential. Also if you have converted a room above a garage or in a loft space where the flue passes through, these can be particularly vunerable rooms for carbon monoxide.

The killer below ground


It's not just gas appliances that can cause a problem. If you live in an area where coal mining was carried out in the past, there have been issues where bulding work has disturbed seams of trapped gasses under the ground. These gasses have then entered properties via airbricks and under the floor, and in some cases this has led to death. This is very rare, however it has happened in this country within the last five years. Be especially wary if you or your neighbours have had extension work done and there has been a history of mining in the area. The digging of the footings can cause the gasses to be released from underneath the ground.

Remember, keep yourselves safe.



For the small cost of a Carbon Monoxide Alarm, they could save your life!