Carbon monoxide is known as the silent killer. This colourless, odourless gas claims lives every year in UK homes, and landlords have a legal duty to protect their tenants from this invisible threat.
The law on CO alarms in rental properties has changed significantly. If you're a landlord in England, understanding your obligations under the Smoke and Carbon Monoxide Alarm Regulations is essential to keep your tenants safe and avoid substantial penalties.
Key Points: CO Alarm Requirements for Landlords
- CO alarms are legally required in any room with a fixed combustion appliance (excluding gas cookers)
- Alarms must be in working order at the start of each tenancy
- Penalties of up to £5,000 for non-compliance
- Requirements apply to all private rented properties in England
- The 2022 regulations expanded requirements to include gas and oil appliances
The Legal Framework: Smoke and Carbon Monoxide Alarm Regulations
The Smoke and Carbon Monoxide Alarm (England) Regulations 2015, as amended by the Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022, set out the legal requirements for CO alarms in private rented properties.
The 2022 amendments significantly strengthened the requirements. Previously, CO alarms were only mandatory in rooms containing solid fuel appliances such as wood burners or coal fires. The updated regulations expanded this to include all fixed combustion appliances.
These regulations apply to:
- All private rented properties in England
- Tenancies under an assured shorthold tenancy (AST)
- Properties let under other types of tenancy or licence
The regulations place specific duties on landlords to install and check carbon monoxide alarms, with enforcement powers given to local housing authorities.
Where Must CO Alarms Be Installed?
Under the regulations, you must install a carbon monoxide alarm in any room used as living accommodation that contains a fixed combustion appliance. This includes:
Covered Appliances
- Gas boilers (including combi boilers)
- Gas fires and heaters
- Oil-fired boilers and heaters
- Wood-burning stoves and log burners
- Coal fires and multi-fuel stoves
- Open fires (with solid fuel)
- Paraffin heaters (if fixed)
Exclusions
The regulations specifically exclude gas cookers. However, while not legally required, installing a CO alarm in the kitchen remains good practice as cookers can produce carbon monoxide if faulty or poorly ventilated.
If your rental property has a gas boiler in a cupboard within a bedroom, you need a CO alarm in that bedroom. The same applies to any room where a combustion appliance is located, regardless of whether tenants use that appliance.
Common Installation Scenarios
Boiler in kitchen: CO alarm required in the kitchen
Boiler in bedroom cupboard: CO alarm required in the bedroom
Boiler in hallway cupboard: CO alarm required in the hallway (if it's used as living accommodation) or in the nearest room used as living accommodation
Gas fire in living room: CO alarm required in the living room
Wood burner in lounge: CO alarm required in the lounge
Oil boiler in utility room: CO alarm required if the utility room is used as living accommodation
Types of CO Alarms for Rental Properties
When selecting CO alarms for your rental property, you have several options. The regulations don't specify a particular type, but you should choose alarms that meet BS EN 50291 (the European standard for carbon monoxide detectors).
Battery-Powered Alarms
- Lower upfront cost
- Easy to install
- Require battery replacement (typically every 1-3 years)
- Suitable for most situations
- Check battery at each tenancy change
Best for: Properties where hardwiring is impractical or cost-prohibitive
Mains-Powered Alarms (with Battery Backup)
- More reliable long-term operation
- Battery backup ensures operation during power cuts
- Higher installation cost (requires electrician)
- Less maintenance than battery-only alarms
Best for: New-build properties, major refurbishments, or landlords wanting minimal ongoing maintenance
Sealed Long-Life Battery Alarms
- Sealed lithium battery lasting 7-10 years
- No battery replacement needed during the unit's life
- Tamper-resistant
- Replace the entire unit when the battery expires
Best for: Rental properties where you want reliability without ongoing battery changes
Regardless of which type you choose, all CO alarms have a limited lifespan. Most manufacturers recommend replacement every 5-7 years, and you should check the expiry date printed on the unit.
Alarm Positioning
For effective detection, position CO alarms:
- At head height on a wall, or on the ceiling
- Between 1-3 metres from the potential source
- Away from windows, doors, or air vents where draughts might affect detection
- Away from areas of high humidity (not directly in bathrooms)
Follow the manufacturer's installation instructions, as recommendations can vary between models.
Testing Requirements
The regulations require landlords to ensure that CO alarms are in proper working order at the start of each new tenancy. This means:
At the Start of Each Tenancy
- Test the alarm by pressing the test button
- Ensure the alarm sounds correctly
- Check the alarm is within its expiry date
- Replace batteries if needed (for battery-powered models)
- Document that testing has been carried out
During the Tenancy
Once the tenancy begins, the responsibility for regular testing passes to the tenant. However, if a tenant reports a faulty alarm, you must repair or replace it as soon as reasonably practicable.
Good practice suggests:
- Including information about alarm testing in the tenant welcome pack
- Advising tenants to test alarms monthly
- Responding promptly to any reports of faulty alarms
- Checking alarms during routine property inspections
Keep records of your alarm tests. Note the date, which property, which alarms were tested, and the outcome. These records demonstrate compliance if you're ever challenged.
Penalties for Non-Compliance
Local housing authorities enforce the CO alarm regulations and have significant powers to penalise non-compliant landlords.
Remedial Notice
If a local authority has reasonable grounds to believe you haven't complied with the regulations, they must serve a remedial notice. This notice specifies:
- What action you must take
- The deadline for compliance (at least 28 days from when the notice is served)
Penalty Charges
If you fail to comply with a remedial notice within the specified period, the local authority can:
- Arrange for the work to be done themselves
- Impose a penalty charge of up to £5,000
The maximum penalty is £5,000 for each breach, and authorities can impose multiple penalties for ongoing non-compliance.
Impact on Tenancies
Non-compliance with CO alarm requirements can also affect your ability to regain possession of your property. Courts have become increasingly focused on landlord compliance with safety regulations, and demonstrating compliance is part of building a positive landlord-tenant relationship.
Best Practices for Landlords
Meeting the minimum legal requirements is essential, but going beyond them demonstrates good practice and provides better protection for your tenants.
Install More Than the Minimum
Consider installing CO alarms in:
- Bedrooms (even if no appliance is present) for overnight detection
- Kitchens (despite the gas cooker exemption)
- Any room where tenants spend significant time
Choose Quality Alarms
- Purchase alarms from reputable manufacturers
- Look for the BSI Kitemark or other quality certification
- Check the alarm meets BS EN 50291
- Keep purchase receipts for your records
Create a Maintenance Schedule
- Note the expiry date of each alarm
- Schedule battery replacements (for non-sealed units)
- Plan ahead for end-of-life replacements
- Include CO alarm checks in your regular property inspection routine
Educate Your Tenants
Provide tenants with:
- Information about CO poisoning symptoms (headache, dizziness, nausea, confusion)
- Instructions for testing the alarm
- Guidance on what to do if the alarm sounds (evacuate, call 999, do not re-enter)
- Contact details for reporting faulty alarms to you
Document Everything
Maintain records of:
- Alarm installation dates
- Test results at the start of each tenancy
- Any repairs or replacements
- Tenant communications about alarm safety
CO Alarms and Other Landlord Obligations
Carbon monoxide alarm requirements sit alongside your other safety duties. Understanding how they connect helps ensure comprehensive compliance.
Gas Safety
Your annual gas safety check (required under the Gas Safety (Installation and Use) Regulations 1998) should identify any CO risks from gas appliances. However, this doesn't remove the need for CO alarms, which provide ongoing protection between inspections.
Smoke Alarms
The same regulations require smoke alarms on every storey of your rental property where there is a room used as living accommodation. You must ensure these are working at the start of each tenancy too. For detailed guidance, see our guide to smoke alarm regulations for landlords.
HMO Requirements
If you operate an HMO (House in Multiple Occupation), you may have additional fire safety requirements including enhanced alarm systems. The CO alarm requirements apply to HMOs just as they do to single-let properties.
Need to check all your compliance requirements? Use our free Landlord Compliance Checker to assess your property against all the key legal requirements and get a personalised action plan.
When the Alarm Sounds
If a tenant reports that a CO alarm has sounded, take it seriously:
- Advise them to evacuate immediately and not re-enter until safe
- Call the gas emergency line (0800 111 999) if gas is suspected
- Arrange an urgent inspection by a Gas Safe registered engineer
- Do not allow re-occupation until the source is identified and resolved
- Replace the alarm if it has been triggered (some alarms need replacement after activation)
Carbon monoxide alarms save lives. A false alarm is inconvenient; ignoring a real alarm can be fatal.
Frequently Asked Questions
No. The regulations specifically exclude gas cookers from the requirement to install a CO alarm. However, installing one in the kitchen is still good practice, as cookers can produce carbon monoxide if faulty or poorly maintained.
You must ensure CO alarms are in proper working order at the start of each new tenancy. During the tenancy, responsibility for regular testing passes to the tenant, but you should repair or replace faulty alarms promptly when reported.
The regulations don't specify a type, but the alarm must meet the BS EN 50291 standard. You can choose battery-powered, mains-powered with battery backup, or sealed long-life battery alarms. Sealed units with 7-10 year batteries are popular with landlords as they require minimal maintenance.
Yes. If you fail to comply with a remedial notice from your local authority, you can face a penalty charge of up to £5,000. The authority can also arrange for the work to be done and recover costs from you.
Summary
Carbon monoxide alarm requirements are a non-negotiable part of being a landlord in England. The Smoke and Carbon Monoxide Alarm Regulations 2022 require you to install CO alarms in any room containing a fixed combustion appliance (excluding gas cookers) and ensure they're working at the start of each tenancy.
With penalties of up to £5,000 for non-compliance and the very real risk that carbon monoxide poses to your tenants' lives, compliance is both a legal necessity and a moral responsibility.
For comprehensive guidance on all your landlord obligations, see our complete Landlord Compliance Guide, and use the Landlord Compliance Checker to assess your property in minutes.
This article provides general guidance on carbon monoxide alarm requirements for landlords under English law. It is not legal advice. Requirements may differ in Scotland, Wales, and Northern Ireland. Always consult current regulations and seek professional advice for your specific circumstances.