Carbon monoxide alarms for homes with stoves and fireplaces

What carbon monoxide is

Carbon monoxide (CO) is a gas produced when fuel burns without enough oxygen. Wood, pellets, charcoal, gas and oil can all produce it. You cannot see it, smell it or taste it, and it builds up quietly in a room.

Breathing it in stops your blood carrying oxygen properly. Early symptoms are easy to mistake for something else:

• headache,
• dizziness,
• nausea,
• tiredness or confusion,
• shortness of breath.

A warning sign is when several people in the house, or pets, feel unwell at the same time and feel better when they go outside. If you suspect CO poisoning, get everyone into fresh air and call 112.

How CO gets into the house

A working flue carries combustion gases up and out. When the flue cannot do its job, gases come back into the room. Common causes in Maltese homes:

• A blocked flue. Bird nests, fallen debris or soot and creosote build-up narrow or close the flue. See bird nests in chimneys and what is creosote.
• Poor draw on a cold flue. Chimneys unused since last winter are cold and damp, and may struggle to draw on the first fires of the season.
• Damaged or old flues. Older stone chimneys in farmhouses and townhouses may have cracks, gaps or shared walls with neighbours.
• Not enough air. Modern windows and sealed rooms can starve a stove or fireplace of the air it needs.
• Wet fuel. Damp wood burns poorly and produces more smoke and gases. See the best firewood for a wood burner.

Smoke coming into the room is a visible warning. CO can come in without visible smoke. Our guide on why a fireplace smokes into the room covers the visible signs.

Why an alarm is the only reliable warning

You will not smell CO, and symptoms can be put down to a cold or a long day. People can also be asleep when levels rise. A CO alarm measures the gas and sounds before levels become dangerous, which gives you time to act. That is why an alarm matters even if you are careful with your fire.

Where to fit CO alarms

General guidance:

• In every room with a stove, fireplace or other fuel-burning appliance.
• Near sleeping areas, especially if bedrooms are close to the fireplace or above it.
• Not directly above or next to the appliance, and not near windows, vents, extractor fans or in dead air spaces such as corners.

But the most important source is the instruction leaflet that comes with your alarm. Different models are designed for different positions and heights, and the manufacturer’s guidance is what that alarm was tested for. Keep the leaflet somewhere you can find it.

Choosing an alarm

• Look for an alarm made to a recognised European standard for CO alarms, which will be marked on the packaging.
• Battery alarms with a long-life sealed battery are easy to fit and maintain.
• Check the expiry or replacement date. CO sensors do not last for ever.
• Combined smoke and CO alarms are available, but make sure each function suits where you are putting it.

Testing and maintenance

• Test monthly using the test button.
• Test before the heating season, in September or October, along with your pre-winter safety checks.
• Replace batteries as the leaflet says, or the whole alarm when it reaches its end-of-life date.
• Keep it clean of dust, and never paint over it.

If the alarm sounds

1. Stop using the stove or fireplace. Do not add more fuel.
2. Open doors and windows if you can do so quickly.
3. Get everyone, including pets, outside into fresh air.
4. Call 112 if anyone has symptoms.
5. Do not use the appliance again until a professional has found and fixed the cause.

Prevention: keep the flue clear

An alarm warns you. A clean, working flue prevents the problem in the first place:

• Sweep at least once a year before the season, and more for heavy use. See how often to sweep a chimney.
• Burn only dry, seasoned wood or good-quality pellets.
• Have pellet stoves serviced, not just swept. See our pellet stove servicing.

We arrange chimney sweeping and stove checks across Malta and Gozo. Book your sweep before the first fire of the season.