HMO Carbon Monoxide Alarm Checks in London
Identify the fixed combustion appliances in every tenant room and shared area, check whether the required alarms are present and working, and create a useful dated record for your HMO file. Send the appliance schedule, alarm details, licence wording and access notes before booking.
Alarm sounding or somebody feels unwell?
Do not wait for a booking. Follow the alarm instructions, move into fresh air and call the National Gas Emergency Service on 0800 111 999 from a safe place. Seek urgent medical advice for possible exposure.
Read HSE carbon monoxide emergency guidanceWhich parts of an HMO need a carbon monoxide alarm?
The HMO label does not decide the alarm count. Start with an appliance-by-appliance walk-through. Government guidance for England links the requirement to every room used wholly or partly as living accommodation that contains a fixed combustion appliance, excluding a gas cooker.
Fixed boilers
A fixed gas or oil boiler is a combustion appliance. Record the room or enclosure, the fuel and the alarm serving that room.
Gas and solid-fuel fires
Gas fires, log burners and coal appliances burn fuel to create heat. Include tenant bedrooms, lounges and shared rooms where they are installed.
Gas cookers
A gas cooker is excluded from this specific alarm trigger. It remains subject to appropriate gas safety, maintenance and ventilation duties.
More than bedrooms
Living accommodation is interpreted broadly. Government guidance includes bathrooms and lavatories, and classes a hall or landing as a room for these regulations.
Do not rely on an old room list. A converted HMO may have a boiler moved into a bedroom, a new gas fire, a decommissioned stove or a flue route that is not obvious from the tenancy schedule. Confirm the current physical layout and tell the checker about any appliance that is boxed in, unused or inaccessible.
The legal route differs, but the safety outcome is similar
The official guidance says the alarm regulations apply directly to unlicensed HMOs. Licensed HMOs are exempt from Parts 1 to 5 only because the regulations also amended the HMO licensing framework to impose similar requirements. That distinction matters when you describe the evidence needed.
For a licensed HMO, check the current licence and any schedule supplied by the borough. A council may ask for a declaration, alarm schedule, installation evidence, test record or confirmation that faults have been resolved. Do not describe a generic test sheet as a council-issued certificate or proof of compliance with every licence condition.
Owner-occupied shared accommodation, long leases, student halls, hotels, care homes and other listed arrangements can be excluded from the alarm regulations. If the tenure is unusual, send the agreement and ask the relevant authority or a legal adviser to confirm the position.
What an HMO CO alarm “certificate” can and cannot prove
“Carbon monoxide alarm certificate” is a common customer phrase, but the regulations do not create one nationally prescribed certificate with an annual expiry date. The legal duties concern alarm provision, a working-order check on the first day of a new tenancy, and prompt repair or replacement after a reported alarm is found faulty.
Select the alarm for the building and its residents
The regulations do not prescribe mains power or battery power and do not set a single mounting position. Government guidance recommends choosing alarms for the building and residents, using products compliant with British Standard BS 50291 and following the manufacturer’s installation instructions.
As general guidance, the government describes a position at head height on a wall or shelf, approximately one to three metres from the potential source. The manufacturer’s instructions remain the controlling installation guide for the chosen alarm and room.
Consider the people who must receive the warning. Residents who are deaf or hard of hearing may need a vibrating or flashing alert rather than an audible alarm alone. Record any agreed accessibility provision and do not assume one device suits every occupier.
Testing, tenant information and fault handling
If access is refused or delayed, keep the notices, messages and proposed appointment times. Government guidance expects landlords to take reasonable steps, work with tenants and retain written evidence of access attempts.
A CO alarm check does not replace appliance safety work
Carbon monoxide can be produced when gas, oil, wood or coal does not burn properly. An alarm is an important warning device, but the HSE also advises that appliances should be properly installed and maintained, with chimneys swept where relevant. Arrange the correct competent person for each fuel and appliance.
What to send before you request an HMO CO alarm check
- Property: full London address, postcode, number of storeys, letting rooms and shared areas.
- Appliances: every boiler, gas fire, oil appliance, stove or other fixed combustion appliance, with its room and fuel.
- Existing alarms: room, make or model, power type, installation date, replace-by date and any current warning or fault.
- Reason: new tenancy, licence condition, council request, agent handover, reported fault, replacement programme or combined inspection.
- Residents: any visual, vibrating, linked or other accessible warning needs that affect alarm selection.
- Access: tenant notice, keys, room restrictions, day contact and the deadline for the completed record.
HMO carbon monoxide alarm FAQs
Does every bedroom in an HMO need a carbon monoxide alarm?
Not automatically. In England, the requirement is linked to a room used wholly or partly as living accommodation that contains a fixed combustion appliance, except a gas cooker. A bedroom containing a gas fire or boiler would therefore need attention, while a bedroom with no such appliance is not brought into scope by the carbon monoxide alarm rule simply because it is let separately. HMO licence conditions may add property-specific requirements.
Do the carbon monoxide alarm regulations apply to a licensed HMO?
Licensed HMOs are exempt from Parts 1 to 5 of the Smoke and Carbon Monoxide Alarm Regulations because the regulations also introduced similar alarm requirements through HMO licensing obligations. Unlicensed HMOs are covered directly where the tenancy is not otherwise excluded. In both cases, check the current licence conditions, appliance layout and local authority request rather than assuming the paperwork route is identical.
Does a room containing a gas boiler need a CO alarm?
A fixed gas boiler is a fixed combustion appliance. If it is in a room used wholly or partly as living accommodation, the government guidance says a carbon monoxide alarm should be equipped in that room. The same principle can apply to fixed oil boilers, gas fires and wood or coal-burning appliances. Follow the alarm manufacturer’s installation instructions for its position.
Are gas cookers excluded from the HMO CO alarm requirement?
Gas cookers are excluded from the specific fixed-combustion-appliance trigger in these alarm regulations. That exclusion does not mean a cooker can be ignored for gas safety, maintenance or ventilation. If a room also contains a boiler, gas fire or another fixed combustion appliance, the separate appliance can still create the carbon monoxide alarm requirement.
Is an HMO carbon monoxide alarm certificate a prescribed legal certificate?
The regulations do not prescribe a nationally standardised certificate with a fixed expiry date. They require suitable alarm provision, a working-order check at the start of a new tenancy and action when a reported alarm is found faulty. A dated inspection or test record can help demonstrate what was checked for a licence, inventory or property file, but it should describe its scope accurately.
How often should HMO carbon monoxide alarms be tested?
A landlord must ensure each required alarm is in proper working order on the day a new tenancy begins. Government guidance advises residents to test alarms regularly in line with the manufacturer’s instructions. If a tenant reports a possible fault and the alarm is found not to work, the landlord must repair or replace it as soon as reasonably practicable. Keep dated records of checks and reported faults.
Does a CO alarm check replace the annual gas safety check?
No. A CO alarm check concerns the alarm, its location and working-order evidence. An annual landlord gas safety check examines relevant gas appliances and flues and produces a gas safety record. A working alarm does not prove that a boiler, fire, cooker, chimney or flue is safe, and it does not replace servicing by a competent person.
What should tenants do if a CO alarm sounds or they suspect exposure?
Treat it as a safety issue, not a certificate enquiry. Follow the alarm instructions, move into fresh air, stop using the suspected appliance if it is safe to do so and call the National Gas Emergency Service on 0800 111 999 from a safe place. Anyone with possible carbon monoxide symptoms should seek urgent medical advice and explain that carbon monoxide exposure is suspected.
Ready to arrange the right CO alarm check?
Send the London postcode, HMO licence wording, appliance and alarm schedule, access notes and deadline. We will confirm the suitable enquiry route by phone or email.