Do I need a carbon monoxide alarm with a wood burner?

Carbon monoxide (CO) is a poisonous gas that you cannot see, smell or taste. Any appliance that burns fuel can produce it if something goes wrong, such as a blocked flue, poor ventilation or a damaged seal. A working alarm is a cheap and simple safeguard, and in many situations it is now a legal requirement.

In short

• Since 1 October 2022, Building Regulations guidance in England says a CO alarm should be fitted in the same room when a new or replacement fixed combustion appliance is installed in a home. Gas appliances used only for cooking are excluded.
• This covers wood burners and multi-fuel stoves, as well as gas and oil appliances.
• The alarm should be 1 to 3 metres from the stove, on the ceiling or high on a wall.
• Landlords, including social landlords, must fit CO alarms in any room with a fixed combustion appliance other than a gas cooker, and repair or replace faulty alarms.
• Even if no rule applies to you, an alarm is strongly recommended in any room with a stove.

What changed on 1 October 2022?

Two sets of rules changed on the same day in England.

Building Regulations (Approved Document J)

Before October 2022, a CO alarm was only required when a solid fuel appliance was installed. The amended Approved Document J extended this to all fixed combustion appliances, burning solid fuel, gas or oil, with gas appliances used solely for cooking excluded. So if you have a new stove fitted, or replace an existing one, a CO alarm should be installed in the same room as part of the job.

The alarm should comply with BS EN 50291-1. Battery alarms are acceptable, and mains-powered alarms should be Type A, which means they can trigger another device.

Rented homes

The Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022 changed the rules for landlords. Since 1 October 2022, relevant landlords in England, including registered providers of social housing, must:

• make sure a CO alarm is fitted in any room used as living accommodation that contains a fixed combustion appliance, other than a gas cooker,
• make sure at least one smoke alarm is fitted on each storey used as living accommodation,
• repair or replace an alarm as soon as reasonably practicable once told it is faulty.

Councils can fine landlords who do not comply.

Where should a CO alarm go?

Approved Document J gives clear guidance on positioning:

• in the same room as the stove,
• between 1 and 3 metres horizontally from the appliance,
• on the ceiling, at least 300mm from any wall, or
• on a wall, as high as possible and above any doors or windows, but not within 150mm of the ceiling.

Avoid positions right next to the stove, in enclosed spaces such as cupboards, or behind curtains and furniture, as these can stop the alarm working properly. Always follow the alarm manufacturer's instructions too.

What if I already have a stove?

The Building Regulations requirement is triggered when an appliance is installed or replaced, so it does not force homeowners to retrofit an alarm to an existing stove. That said, there is no good reason not to have one. If your stove was fitted before October 2022 and you have no alarm, buying and fitting one is a quick, low-cost step that could save lives. Test it regularly and replace it when it reaches the end of its stated life.

Choosing and looking after a CO alarm

CO alarms are widely available from DIY stores and electrical retailers. When you buy one, look for these points:

• The right standard. Check the packaging says BS EN 50291-1. Avoid cheap "spot" detectors that change colour, as they do not sound a warning.
• A sealed long-life battery. Many alarms come with a battery designed to last the life of the unit, which saves remembering to change it.
• An end-of-life warning. CO sensors wear out. Most alarms have a stated lifespan, often several years, and will chirp or flash when they need replacing. Write the replacement date on the alarm.
• Clear test button. Press it regularly, for example monthly, and whenever you return from time away.

Keep the alarm free of dust, do not paint over it, and never take the battery out to silence it. If it keeps sounding, treat it as a genuine warning until a qualified person has checked the stove.

An alarm is a backstop, not a substitute

A CO alarm warns you when something has already gone wrong. The real protection is a properly installed and maintained stove:

• a correctly sized and sealed flue or liner,
• adequate ventilation where the stove needs it,
• regular chimney sweeping, as explained in our guide on how often to sweep your chimney,
• burning dry fuel, which reduces tar and soot build-up. See the best wood to burn,
• having the stove serviced and its seals and rope checked.

Know the warning signs

Symptoms of CO poisoning can include headaches, dizziness, nausea, tiredness, breathlessness and confusion. They are easily mistaken for flu. If your alarm sounds or you suspect CO, open doors and windows, let the stove go out, leave the room and get fresh air. Seek medical advice if anyone feels unwell, and do not use the stove again until it has been checked by a qualified person.

Part of every compliant installation

A properly certified installation should include a CO alarm positioned to Approved Document J, along with the right hearth, flue and ventilation. Our guide to stove regulations in England covers the full picture. If you are planning a new stove or a replacement for an older stove, get in touch to book a survey and a written quote.