Carbon Monoxide Alarms for Homes with Fireplaces and Stoves

A warm stove can make a room feel reassuringly comfortable, yet carbon monoxide gives no warning smell or visible cloud. A working CO alarm provides an essential warning if this poisonous gas builds up indoors. For homes with fireplaces and wood-burning stoves, carbon monoxide safety depends on combining detection with adequate air supply, a sound flue and regular maintenance.

What to do when a CO alarm sounds

Warn everyone, leave the building immediately and call 112 from outside. Treat a carbon monoxide alarm as an emergency even if nobody feels unwell.

1. Get everyone into fresh air. Take pets if they are readily accessible, without delaying your escape.
2. Do not stay inside to investigate, silence the alarm or manage the fire. Open an accessible door or window only if this causes no delay in leaving.
3. Tell the 112 operator that a CO alarm has activated or that you suspect carbon monoxide exposure. Mention anyone who feels unwell or remains inside.
4. Stay outside until the emergency services say it is safe to return. An alarm becoming silent does not establish that the building is safe.
5. Keep the fireplace or stove out of use until a competent specialist has identified and corrected the cause.

Headache, nausea, dizziness, unusual tiredness and confusion can indicate CO poisoning. If you suspect exposure, leave and seek emergency help even when no alarm has sounded. Do not re-enter an unsafe building to attempt a rescue; tell the emergency operator where the person is.

How fireplaces and stoves create a CO hazard

Carbon monoxide forms during incomplete combustion of fuels such as wood and gas. The danger indoors arises when combustion gases enter living spaces instead of being safely discharged outside.

Possible causes include a blocked chimney, leaking flue connections, inadequate combustion air or poor chimney draught. More than one problem may contribute: an appliance producing excessive CO becomes particularly dangerous when its flue also fails to remove the gases.

Renovation can change how an existing installation behaves. Draught-proofing may reduce the air available to a stove that draws combustion air from the room. A powerful extractor fan can create negative pressure and interfere with flue draught if replacement air is insufficient.

Have the air supply and flue assessed when changing windows, ventilation or extraction equipment. A recent service is valuable, but it does not remove the need for an alarm.

CO alarms and smoke alarms detect different hazards

A smoke alarm detects smoke particles associated with fire. A carbon monoxide alarm detects CO gas. An ordinary smoke alarm cannot provide CO protection, and a standalone CO alarm cannot replace smoke detection.

A carbon dioxide monitor, often labelled CO₂, measures a different gas and is also unsuitable as a replacement.

Combination smoke and CO alarms contain both detection functions, but their suitability depends on the installation position. Dutch fire service advice limits their use to rooms containing a combustion appliance, where the recommended mounting heights can coincide. Elsewhere, separate alarms allow each sensor to be positioned appropriately.

Choosing a carbon monoxide alarm for a wood stove

Look for a domestic alarm with EN 50291-1 stated on its packaging or instructions. This standard covers the testing and performance of CO detection equipment for homes.

Before buying, check these practical details:

• Installation suitability: Confirm that the model supports the mounting position required in your room.
• Power supply: Understand whether it uses replaceable batteries, a sealed battery or mains power with backup.
• Service life: Check the replacement date and how the unit signals sensor expiry.
• Warning signals: Choose a model with clear instructions explaining its alarm, fault and battery warnings.
• Audibility: Consider whether occupants will hear it from bedrooms with doors closed. Compatible interconnected alarms or specialist alerting equipment may be appropriate.

A display can provide useful information, but a low or zero reading is not proof that an appliance or flue is safe. Domestic CO alarms respond according to concentration and exposure time; they do not necessarily sound as soon as any CO is present.

Install an alarm in each room containing a combustion appliance, and consider additional protection in bedrooms and other occupied rooms.

Positioning alarms under Dutch guidance

The Dutch fire service’s CO alarm placement guidance distinguishes between rooms with and without a combustion appliance.

In the fireplace or stove room

The guidance recommends ceiling mounting, centrally in the room, with the alarm:

• Between 1 and 3 metres horizontally from the potential CO source.
• At least 30 centimetres from surrounding walls.
• Clear of air inlets, outlets and other ceiling objects.

For a sloping ceiling, mount it on the slope while retaining the horizontal separation.

CO mixes with air. In an appliance room, warm air can initially carry it upwards, which explains the ceiling recommendation.

In bedrooms and other rooms

In a bedroom without a combustion appliance, position an additional CO alarm at sleeping breathing height. In other rooms without an appliance, use breathing height appropriate to sitting or standing.

Keep sensors clear of curtains, furniture and ventilation openings. Check the model’s approved mounting orientation. If its instructions differ from Dutch guidance, contact the supplier to resolve the placement before installation.

Keep detection and maintenance working together

Test the alarm using its test button at the interval specified by the manufacturer. Clean it as instructed, keep its openings unobstructed and never paint it. Do not test it with exhaust fumes, a flame or burning materials.

Learn the difference between the model’s emergency alarm and its battery, fault and end-of-life signals. An occasional chirp may indicate a maintenance problem, but sound patterns vary. If you cannot confidently identify an unexplained warning, treat it as a possible CO emergency.

Replace the complete alarm by its stated expiry date. A new battery does not renew an ageing sensor.

Alongside these checks, arrange regular stove servicing and chimney sweeping, with the frequency suited to the appliance, fuel and use. Keep required ventilation openings clear. Before the heating season, confirm that the alarms work and that everyone in the household knows the escape route and the instruction to call 112 from outside.