Do I need a carbon monoxide alarm? The rules for landlords and homeowners

The rules for landlords

The Smoke and Carbon Monoxide Alarm (England) Regulations 2015, as amended in 2022, apply to private and social landlords. Since 1 October 2022, a relevant landlord must:

• Fit at least one smoke alarm on each storey of the home that has a room used as living accommodation.
• Fit a carbon monoxide alarm in any room used as living accommodation that contains a fixed combustion appliance, other than a gas cooker. A bathroom or toilet counts as a room for this purpose.
• Check the alarms are in proper working order on the day a new tenancy begins.
• Repair or replace an alarm as soon as reasonably practicable after a tenant reports it and it is found to be faulty.

Local housing authorities enforce the rules. Where a landlord is in breach, the council must serve a remedial notice, which the landlord has 28 days to comply with. If they do not, the council can arrange the work and impose a civil penalty of up to £5,000.

What counts as a fixed combustion appliance?

Government guidance describes it as a fixed apparatus where fuel of any type is burned to generate heat: gas or oil boilers, gas fires and log-burning stoves, for example. Gas cookers are excluded from the landlord rule. In the government's view, a purely decorative fireplace that cannot be used is not a fixed combustion appliance.

The rules for homeowners fitting a new boiler

Homeowners are not required to retrofit alarms in their own homes, but the Building Regulations apply when work is done. Approved Document J, updated on 1 October 2022, says a carbon monoxide alarm should be fitted when a fixed combustion appliance that burns gas (other than an appliance used only for cooking), oil or solid fuel is installed in a new home, or when a new or replacement appliance is installed in an existing home. So when your boiler is replaced, expect your installer to make sure there is an alarm in the same room. See our guide to the rules for a new boiler.

Which type of alarm should be fitted?

• Approved Document J says alarms should comply with BS EN 50291 and either have a battery designed to last the working life of the alarm, with a warning when the alarm is near the end of its life, or be mains powered with fixed wiring (not plug-in) and a sensor failure warning.
• For landlords, the regulations do not specify battery or mains alarms. Government guidance says alarms should comply with BS EN 50291 and that, where battery alarms are chosen, sealed-for-life batteries are the better option.

Where should a carbon monoxide alarm go?

Always follow the alarm manufacturer's instructions. Approved Document J gives this placement guidance for an alarm fitted with a new appliance:

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

Government guidance for landlords says alarms are generally positioned at head height on a wall or shelf, roughly 1 to 3 metres from the appliance. Where the two differ, follow the manufacturer's instructions for the alarm you fit.

Is an alarm a substitute for a gas safety check?

No. An alarm warns you that carbon monoxide is already present. Preventing it depends on correct installation and regular servicing. Landlords must still have every gas appliance and flue they provide checked every 12 months by a Gas Safe registered engineer; see our landlord gas safety certificate (CP12) guide. Homeowners should have their boiler serviced every year; see how often a boiler should be serviced.

What to do if a carbon monoxide alarm goes off

• Open windows and doors, and turn off gas appliances if it is safe to do so.
• Leave the property and call the National Gas Emergency Service on 0800 111 999.
• Seek medical advice if anyone has headaches, dizziness, nausea or breathlessness.
• Do not use the appliances again until a Gas Safe registered engineer has checked them.

Does this apply in Wales and Scotland?

This guide covers England. Wales and Scotland have their own rules on smoke and carbon monoxide alarms in homes, so landlords with property there should check the rules for that nation.

This guide is general information, not a substitute for an on-site assessment by a Gas Safe registered engineer. If you smell gas, call 0800 111 999.