What are the legal requirements for a carbon monoxide alarm?

Carbon monoxide alarm rules depend on where the property is, whether it is rented, and whether a new or replacement combustion appliance is being installed. England and Scotland do not use exactly the same housing rules, so a checklist copied from one nation can be incomplete in the other.

This guide covers the position for ordinary homes in England and Scotland as at October 2026. It is general information, not legal advice. Houses in multiple occupation, licensed properties, new building work and unusual premises can have extra requirements.

The short answer

• Rented homes in England: the landlord must provide a carbon monoxide alarm in any room used as living accommodation that contains a fixed combustion appliance, except a gas cooker.
• Owner-occupied homes in England: there is not a general rule requiring every existing home to be retrospectively fitted solely because it is owner-occupied. Building Regulations apply when a new or replacement fixed combustion appliance is installed.
• Homes in Scotland: satisfactory carbon monoxide detection forms part of the Tolerable Standard and applies across tenures, including owner-occupied and rented homes.
• Solid-fuel appliances: wood burners, coal fires and other fixed solid-fuel appliances are covered. They are not an exception to the rules.

England: rules for landlords

The Smoke and Carbon Monoxide Alarm (England) Regulations require relevant landlords to ensure that a carbon monoxide alarm is equipped in any room used wholly or partly as living accommodation that contains a fixed combustion appliance other than a gas cooker.

A fixed combustion appliance can include a gas boiler, gas fire, oil appliance, wood-burning stove or other fixed appliance that burns fuel. “Room” is not limited to a lounge or bedroom; halls and landings can count where the regulations treat them as living accommodation.

The landlord must make sure each required alarm is working on the first day of a new tenancy. If a tenant or their nominated representative reports that a prescribed alarm is not working, the landlord must investigate and repair or replace it as soon as reasonably practicable.

The law does not make a gas cooker on its own trigger the carbon monoxide alarm duty under these regulations. That exclusion should not be used to ignore a separate risk assessment, manufacturer instruction, licence condition or building requirement.

Did England’s rule used to mention only solid fuel?

Yes. The original 2015 landlord rules focused the carbon monoxide requirement on rooms with solid-fuel appliances. From 1 October 2022, the amendment widened the duty to rooms containing a fixed combustion appliance, except a gas cooker. That means a room containing a gas boiler can now trigger the rented-sector requirement.

Older articles that say a landlord needs a CO alarm only beside a wood burner or coal fire are out of date for England’s covered tenancies.

England: what about homeowners?

For an existing owner-occupied home, the landlord regulations do not apply. There is no single rule saying every older owner-occupied home must be retrofitted in all circumstances simply because someone owns and lives in it.

However, Building Regulations require appropriate warning when a combustion appliance is provided. Current Approved Document J guidance extends carbon monoxide alarm provision when a new or replacement fixed combustion appliance is installed in a dwelling. This applies across fuel types, with gas cookers treated differently.

So if a boiler, fire, stove or other fixed combustion appliance is being installed or replaced, the installer should address the alarm requirement as part of compliant work. Separate conditions can also arise through building control, insurance, warranties or local housing enforcement.

Even where a legal retrofit duty is not triggered, HSE strongly recommends carbon monoxide alarms as an additional precaution. An alarm is not a substitute for correct installation, maintenance and servicing.

Scotland: the rules apply more widely

Since 1 February 2022, satisfactory carbon monoxide detection has formed part of Scotland’s Tolerable Standard for all houses, regardless of tenure. That means the standard is relevant to homeowners as well as landlords.

Scottish Government guidance says homes should have satisfactory warning where carbon monoxide may arise from fixed combustion appliances. Private-landlord guidance requires detection in rooms containing a fixed combustion appliance—such as a boiler, fire, heater or stove burning gas, oil or solid fuel—or relevant flue, with cooking-only appliances excluded.

Landlords must ensure a rented home meets the Tolerable Standard through the Repairing Standard. Owner-occupiers are responsible for their own home. Scottish fire-alarm rules also require interlinked smoke and heat alarms, but a carbon monoxide alarm is a different device; do not assume every CO alarm must be interlinked in the same way without checking the current Scottish guidance and product instructions.

Are wood burners and open fires covered?

Yes. Solid fuel includes wood, coal and similar carbon-based fuels. A fixed wood-burning stove or open fire can produce carbon monoxide if combustion, ventilation, flue performance or maintenance is inadequate.

In rented homes in England, a fixed solid-fuel appliance falls within the wider fixed-combustion-appliance rule. In Scotland, solid-fuel appliances are included within the Tolerable Standard guidance. In England, installing or replacing a fixed solid-fuel appliance also brings Approved Document J guidance into play.

What type of alarm should you use?

Use a carbon monoxide alarm that complies with the appropriate current British Standard, normally BS EN 50291 for domestic use, and follow the manufacturer’s instructions. Check the expiry or replace-by date because the sensor has a limited working life.

Do not buy an alarm solely because it is cheap or because its case resembles a recognised product. Use a reputable supplier, retain the instructions, and record installation and replacement dates.

Where should a carbon monoxide alarm go?

Position depends on the room, appliance and alarm instructions. Government guidance commonly places the alarm in the same room as the appliance, away from corners, obstructions, windows, extractors and excessive moisture. The exact height and distance must follow the product instructions and the applicable national guidance.

Do not put the alarm inside a boiler cupboard unless the manufacturer and relevant guidance specifically permit it. A badly positioned alarm may respond slowly or give misleading reassurance.

Who tests and maintains it?

In an English rented home, the landlord must test required alarms on the first day of a new tenancy and must arrange repair or replacement after a tenant reports a fault. Tenants should test alarms regularly according to the manufacturer’s instructions and promptly report problems.

In Scotland, the homeowner or landlord is responsible for ensuring the property meets the applicable standard. A landlord should keep clear records of installation, testing, reports and replacements.

Never paint an alarm, cover it during normal use or remove its battery to silence a warning. Replace an expired or faulty unit promptly.

What should you do if the alarm sounds?

• Move everyone into fresh air and leave the property.
• Call the National Gas Emergency Service on 0800 111 999 if gas or a gas appliance may be involved.
• Seek urgent medical help if anyone has headache, dizziness, nausea, confusion, weakness, chest pain or loss of consciousness.
• Do not re-enter or use the appliance until competent professionals say it is safe.
• Do not remove the boiler casing or try to find the source yourself.

Carbon monoxide has no smell, colour or taste. A sounding alarm must not be dismissed because nobody can smell gas.

Common misunderstandings

“A boiler service means I do not need an alarm”

Incorrect. Maintenance reduces risk but does not replace required detection. An alarm also does not replace servicing.

“Only landlords need CO alarms”

Incorrect in Scotland, where the Tolerable Standard applies to all houses. In England, building requirements can apply to owner-occupied homes when fixed combustion appliances are installed or replaced.

“The law covers only solid fuel”

That is outdated for covered rented homes in England. The 2022 amendment widened the landlord duty to fixed combustion appliances other than gas cookers.

“A smoke alarm detects carbon monoxide”

Not unless it is a combined product specifically certified for both functions. Ordinary smoke alarms and CO alarms detect different hazards.

Related help

• Boilers and carbon monoxide: warning signs and safe action
• Landlord gas safety certificates: a plain-English guide
• How often should you service a boiler?