Compliance & Safety Certificates
Carbon monoxide alarm regulations: a landlord guide
Carbon monoxide poisoning kills around 40 people in England and Wales every year and sends hundreds more to hospital. As a landlord, you have a legal duty to install carbon monoxide alarms in your rental property and the rules changed significantly in October 2022. This article explains exactly what the current regulations require, which rooms are covered, what types of alarm to use, and what happens if you do not comply.
What are the carbon monoxide alarm regulations for landlords?
The rules for England are set out in The Smoke and Carbon Monoxide Alarm (England) Regulations 2015, as significantly amended by The Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022. The amended regulations came into force on 1 October 2022 and apply to all landlords in the private rented sector, as well as to social housing landlords for the first time.
In summary, the current regulations require landlords to:
Install at least one CO alarm in every room that contains a fixed combustion appliance, with the exception of gas cookers.
Ensure all CO alarms are in working order at the start of every new tenancy.
Repair or replace any CO alarm that is found to be faulty as soon as reasonably practicable after the landlord is notified.
What changed in October 2022?
The original 2015 regulations only required CO alarms in rooms containing solid fuel-burning appliances, log burners, open fires, and coal-burning stoves. Gas appliances such as boilers and gas fires were not covered.
The 2022 amendment significantly extended the scope of the rules. From 1 October 2022, CO alarms are required in any room with any fixed combustion appliance, including gas boilers and gas fires, not just solid fuel appliances. This is the most consequential change in the regulations and affects the vast majority of rental properties in England, since most homes have gas central heating with a boiler located somewhere on the premises.
The 2022 amendment also extended the regulations to social housing landlords, who were previously exempt.
Which rooms need a carbon monoxide alarm?
A CO alarm is required in any room of the property that contains a fixed combustion appliance. In practice, for most rental properties this means:
The room containing the gas boiler, most commonly the kitchen, utility room, airing cupboard, or boiler cupboard.
Any room with a gas fire or gas fireplace, real flame or decorative.
Any room with a log burner, wood-burning stove, multi-fuel stove, or open fire.
Any room with an oil-fired boiler or oil-fired heater.
If your property has a combi boiler in the kitchen and a gas fire in the living room, you need CO alarms in both rooms. The requirement is tied to the location of the appliance, not to whether it is a habitable or living space.
Which appliances trigger the CO alarm requirement?
Appliances that are included
The following fixed combustion appliances trigger the requirement:
Gas boilers – including combi boilers, system boilers, and heat-only boilers.
Gas fires and gas fireplaces, whether real flame or decorative.
Log burners, wood-burning stoves, and multi-fuel stoves.
Open coal fires and other solid fuel-burning appliances.
Oil-fired boilers and oil-fired heaters.
LPG-powered fixed appliances.
Biomass boilers.
Appliances that are excluded
Gas cookers, including gas hobs and gas ovens, are specifically excluded from the requirement. A kitchen with only a gas hob and oven but no boiler and no gas fire does not legally need a CO alarm under these regulations. That said, fitting one is strongly recommended as best practice given that any gas-burning appliance can in theory produce CO.
What type of carbon monoxide alarm do I need?
Any alarm you install should comply with British Standard BS EN 50291-1 (electrochemical cell type, for domestic use). Look for the British Kitemark symbol on the packaging as confirmation that the product has been independently tested. There are three main types to consider:
Battery-powered alarms - the simplest and most widely used option. Best practice is to choose a sealed long-life battery alarm (typically 5 to 10 years) so the tenant cannot inadvertently remove the battery.
Mains-wired alarms with battery backup - more reliable and harder to tamper with, but require an electrician to install. Required in some HMO properties under fire safety rules.
Combination smoke and CO alarms - increasingly popular for kitchens and utility rooms. Check that the combination unit meets both BS EN 14604 (smoke) and BS EN 50291-1 (CO) standards.
Check the manufacturer's recommended replacement date printed on the back of the unit. Most CO alarms last 5 to 10 years, after which the sensor degrades and the entire unit must be replaced.
Where should CO alarms be positioned?
Carbon monoxide is approximately the same density as air, so it distributes relatively evenly throughout a room rather than rising to the ceiling like smoke. Positioning guidance:
Mount at approximately head height (1 to 1.5 metres from the floor), on a ceiling or wall, in the same room as the combustion appliance.
Avoid placing it directly adjacent to windows, doors, or extractor fans, as draughts can disperse CO before it reaches the sensor.
Do not place it in a corner where air circulation is restricted.
Follow the manufacturer's positioning instructions, which take precedence over general guidance where there is a conflict.
Testing obligations: what you must do at the start of each tenancy
You are legally required to ensure that all CO alarms are in working order at the start of every new tenancy. Steps to take:
Press the test button on each alarm and confirm it sounds correctly.
Check the replacement date on each unit and replace any that are at or past their expiry.
Document the test date and result in your move-in paperwork (inventory or check-in report).
Provide the tenant with written confirmation that the alarm has been tested.
Show the tenant the location of each alarm, how to test it, and what to do if it sounds.
The obligation to test at the start of each new tenancy applies every time a new tenancy begins, including if you re-let the property after a void period.
Repair and replacement obligations
If a tenant reports a faulty or non-functioning CO alarm, you must repair or replace it as soon as reasonably practicable. Given the life-safety implications, this should be treated as urgent, in practice, within 24 to 48 hours. Keep receipts and records of all replacements. If an alarm is approaching its printed replacement date, replace it proactively.
The division of responsibility is clear. Tenants are responsible for routine testing and for reporting faults. Landlords are responsible for ensuring working alarms are installed and for carrying out all repairs and replacements.
What happens if you do not comply?
Local housing authorities enforce the CO alarm regulations. The process is:
The local authority may serve a remedial notice requiring the landlord to install or repair alarms within 28 days.
If the landlord fails to comply within 28 days, the local authority may arrange for the work to be carried out at the landlord's expense.
The local authority may also impose a civil penalty of up to £5,000.
Non-compliance is also relevant to any HHSRS assessment of the property. Carbon monoxide is a Category 1 HHSRS hazard, and missing alarms could trigger an improvement notice alongside the specific CO alarm enforcement regime.
Scotland, Wales and Northern Ireland
The rules in this guide apply in England only. The other UK nations have their own separate legislation:
Scotland has stricter requirements. Since February 2022, every Scottish home must have interlinked fire and smoke alarms, a heat alarm in the kitchen, and at least one carbon monoxide detector wherever there is a fixed combustion appliance. All alarms must be interlinked so they all sound together if one is triggered.
Wales has its own version of the smoke and CO alarm regulations with broadly similar scope to the English rules, but landlords should check the specific Welsh Government guidance.
Northern Ireland has separate building regulations and safety guidance – check with the relevant local authority and Department for Communities.
CO alarms and your gas safety obligations
Carbon monoxide alarm compliance is a separate legal obligation from your gas safety certificate requirement, but the two are closely connected. Any property with a gas appliance needs both a current Gas Safety Record (renewed every 12 months by a Gas Safe registered engineer) and a CO alarm in the room containing any gas boiler or gas fire. For full detail on your gas safety obligations, see the complete UK landlord guide to gas safety certificates.
Carbon monoxide alarm compliance checklist
Identify every room with a fixed combustion appliance (boiler, gas fire, log burner, oil boiler, etc.).
Confirm a CO alarm complying with BS EN 50291-1 is installed in each of those rooms.
Check the replacement date on every alarm and replace any unit past or approaching its expiry.
Test every CO alarm using the test button and document the result in move-in paperwork.
Confirm your gas safety certificate is current.
Brief the tenant on CO alarm locations and the emergency protocol if it sounds (leave, call 999, call 0800 111 999).
Keep written records of all alarm tests, installations, and replacements in your property file.
Frequently asked questions
Do I need a CO alarm if my rental property has a gas boiler?
Yes. Since October 2022, gas boilers are covered by the CO alarm regulations. You must install at least one CO alarm in the room that contains the boiler, regardless of whether it is a kitchen, utility room, or airing cupboard.
Do I need a CO alarm if there is a gas hob but no boiler?
No – gas cookers are specifically excluded from the regulations. However, fitting one is strongly recommended given that any gas appliance can in theory produce CO.
Who is responsible for testing CO alarms during the tenancy?
The landlord must ensure alarms are working at the start of each tenancy. During the tenancy, tenants are encouraged to test alarms regularly and must report any faults. Once notified, the landlord must arrange repair or replacement as soon as reasonably practicable.
Do I need CO alarms in every flat in a block?
Yes. The obligation applies per dwelling. Each self-contained flat needs its own CO alarms wherever required, regardless of whether the building has communal areas or shared heating.
What should a tenant do if the CO alarm sounds?
Stop using all gas or fuel-burning appliances, leave the building and get fresh air, call 999, and call the Gas Emergency Service on 0800 111 999. Do not re-enter until the property has been inspected and declared safe by a Gas Safe registered engineer.
Is there a requirement to interlink CO alarms in England?
No. Interlinking is not required under the English regulations, unlike Scotland. Standalone alarms in each room containing a combustion appliance satisfy the legal requirement.
Key takeaways
Since 1 October 2022, CO alarms are required in any room with a fixed combustion appliance, including gas boilers and gas fires, not just solid fuel appliances. This affects the vast majority of rental properties in England.
Smoke alarms and CO alarms are separate but complementary obligations, for the rules on where smoke alarms must be installed and what type to use, see the full guide to smoke alarm regulations in rental properties.
Gas cookers are the only combustion appliance type specifically excluded from the requirement.
Alarms must comply with BS EN 50291-1, be tested at the start of every new tenancy, and be repaired or replaced promptly when faulty.
Local housing authorities can serve remedial notices and impose fines of up to £5,000 for non-compliance.
Scotland has stricter requirements including interlinked alarms. Rules also differ in Wales and Northern Ireland.
CO alarm compliance sits alongside your gas safety certificate, EICR, and smoke alarm obligations as a core safety requirement for rental properties in England.
For guidance on smoke alarm requirements, which apply to every storey of the property, not just rooms with appliances, see the article on smoke alarm regulations in rental properties.
Disclaimer: This article is intended for general informational purposes only and does not constitute legal, financial, or professional advice. Landlord and tenant law is subject to change, and the information in this article reflects the position at the time of writing. You should always seek independent legal or professional advice before taking any action in relation to your property or tenancy.
Author
August Team
The August editorial team lives and breathes rental property. They work closely with a panel of experienced landlords and industry partners across the UK, turning real-world portfolio and tenancy experience into clear, practical guidance for small landlords.
