Carbon monoxide alarm services
Carbon Monoxide CO Alarm Certificate
Arrange a CO alarm check, installation, replacement or written property record for a rented home, managed property or handover.
Send the postcode, appliance details, existing alarms, access arrangements and deadline. We will confirm whether battery-operated, mains-powered or specialist CO alarms need to be considered and whether gas-safety work is a separate requirement.
The quick answer
What is a carbon monoxide alarm certificate?
There is no single nationally prescribed domestic document called a carbon monoxide alarm certificate. The term normally describes a dated record of the alarms found, their positions and visible details, the response obtained from the test button and any agreed installation or replacement work.
The record can support a landlord inventory, letting-agent file, maintenance history or property handover. It cannot prove that a boiler, fire, flue or ventilation system is safe, and it does not replace a gas safety record, appliance service, fire-risk assessment or duties applying to the property.
Our starting prices
Carbon monoxide alarm prices
These are from prices for the stated scope. We confirm the alarm specification, quantity, existing wiring, access and any electrical work before booking.
Battery-operated CO alarm
Battery-operated carbon monoxide alarm
From £60 each
Starting price for each agreed battery-operated CO alarm supplied or replaced within the confirmed scope.
Mains-powered CO system
Mains-powered carbon monoxide alarms
From £150 for up to five
Starting price for an agreed mains-powered CO alarm or detector installation covering up to five alarms.
More than five mains alarms
Additional mains-powered CO alarm over five
From £45 each
Starting price for each additional mains-powered CO alarm where the confirmed installation requires more than five.
Immediate safety comes first
What to do if a CO alarm sounds
Treat an alarm as a warning, not as a routine booking request. Follow the alarm instructions, move into fresh air, stop using suspected appliances if it is safe to do so and seek urgent professional or emergency advice.
If anyone has symptoms or you suspect poisoning, call 999. For a suspected gas emergency in Great Britain, call the National Gas Emergency Service on 0800 111 999. Do not re-enter or restart an appliance until appropriate advice says it is safe.
Landlord guide for England
Where covered rented homes need CO alarms
Official guidance says relevant landlords must equip a carbon monoxide alarm in each room used as living accommodation that contains a fixed combustion appliance, except a gas cooker. Examples include gas or oil boilers, log burners and open fires.
The duty follows the room and the fixed combustion appliance, not simply the number of storeys.
Each prescribed alarm must be in proper working order on the first day of a new tenancy.
Landlords must repair or replace an alarm after being informed and establishing that it is faulty.
The regulations do not prescribe battery or mains power as the only option. GOV.UK recommends choosing an alarm for the building and residents, considering BS 50291 and following the manufacturer instructions. Building work, HMO licensing, fire-risk findings or local authority requirements may set an additional standard.
Positioning affects the warning
Where should a CO alarm be fitted?
Use the manufacturer instructions supplied with the chosen alarm. GOV.UK says a CO alarm is generally positioned at head height on a wall or shelf and around one to three metres from the possible source, but a product or property specification may require a different position.
- Identify each fixed combustion appliance
- Confirm whether the room is living accommodation
- Keep the alarm within the permitted distance
- Avoid cupboards, curtains and obstructed positions
- Do not place it beside a window, vent or extractor
- Keep away from excessive damp, heat, cold or dust
- Make the warning audible to intended occupants
- Consider specialist alerts for hearing impairment
Select the device for the property
Battery-operated and mains-powered CO alarms
Power source is only one part of the decision. Confirm the applicable standard, sensor life, fault warning, display, backup supply, fixing method, environmental rating and resident needs.
Battery-operated CO alarms
- Sealed long-life batteries can reduce routine battery changes
- End-of-life and fault warnings should be understood
- The unit still needs correct fixing and positioning
- Expiry and replacement dates should be recorded
Mains-powered CO alarms
- Require a suitable supply and competent electrical installation
- May include backup power and remote signalling
- Compatibility must be checked when extending a system
- New wiring and remedial work change the quotation
Agree the service before attendance
What a CO alarm visit may include
A test-button response confirms the alarm electronics and sounder responded at that moment; it does not expose the sensor to carbon monoxide or prove the appliance is safe.
- Relevant appliances and accessible rooms noted
- Alarm quantity, type and visible position recorded
- Visible damage, contamination or obstruction checked
- Manufacturer, model and expiry details where legible
- Test-button response at attendance recorded
- Battery or mains power information where apparent
- Missing, expired or faulty alarms identified
- Installation or replacement within the quotation
- Separate gas-safety needs signposted
- Dated notes or agreed property record
Do not merge different safety duties
CO alarm, gas safety check and boiler service
A CO alarm warns occupants when it detects carbon monoxide. A landlord gas safety check examines covered gas appliances and flues and produces the statutory gas safety record. A boiler service is maintenance performed to the agreed scope.
One visit may be coordinated where suitable, but each service has its own purpose, competence requirement, price and document.
Prepare the appliance information
What to send before booking
List every boiler, fire, stove and other fixed combustion appliance, its fuel and its room. Photographs of appliances and existing CO alarms can help identify the likely scope before attendance.
Arrange access to all relevant rooms and send any landlord, HMO, insurer, building-control or fire-risk-assessment specification.
A practical booking process
From appliance list to property record
Send property details
Provide the postcode, appliances, rooms, alarms, access, occupancy and deadline.
Confirm the scope
We agree the likely CO alarm type, quantity, installation work and starting price.
Attend and complete
The agreed checks, installation or replacement are completed where access and conditions allow.
Record the outcome
You receive the agreed record, invoice and any notes on separate or remedial work.
UK requirements differ
Check the nation, tenure and appliance
This service page is written mainly for properties in England. Wales requires a working CO alarm in each room of a covered rented home containing a gas appliance, oil-fired combustion appliance or solid-fuel burning appliance. Scotland has separate requirements for homes with carbon-fuelled appliances and its own placement guidance.
Northern Ireland has separate housing and building standards. Always confirm the current rules for the property location, building work, licence and type of accommodation.
Related property services
Coordinate access where several checks are due
Common questions
Carbon monoxide alarm certificate FAQs
What is a carbon monoxide alarm certificate?
There is no single nationally prescribed domestic document called a carbon monoxide alarm certificate. The phrase usually means a dated record of the CO alarms found, their locations, visible details, test-button responses and any installation or replacement work completed during the agreed visit.
How much does a carbon monoxide alarm service cost?
Battery-operated CO alarms start from £60 each. Mains-powered CO alarm or detector installations start from £150 for up to five alarms. If more than five mains-powered alarms are required, each additional alarm starts from £45. The final quotation depends on the alarm specification, existing wiring, access and property requirements.
What is included in the battery-operated CO alarm price?
The price starts from £60 for each agreed battery-operated CO alarm supplied or replaced within the confirmed scope. Device type, compliance standard, position, access and any removal or remedial work must be agreed before attendance.
What is included in the mains-powered CO alarm price?
The mains-powered service starts from £150 for an agreed installation of up to five CO alarms. Where more than five are required, each additional alarm starts from £45. New cabling, circuit alterations, specialist access, compatibility checks and remedial electrical work can change the quotation.
When must a landlord provide a CO alarm in England?
For covered rented homes in England, relevant landlords must equip a carbon monoxide alarm in each room used as living accommodation that contains a fixed combustion appliance, except a gas cooker. Prescribed alarms must work on the first day of a new tenancy, and faulty alarms must be repaired or replaced after the landlord is informed and the fault is established.
Where should a carbon monoxide alarm be installed?
Always follow the alarm manufacturer instructions and the property specification. GOV.UK guidance says a CO alarm is generally positioned at head height on a wall or shelf and around one to three metres from the potential source. Avoid choosing a position from a generic rule if the manufacturer gives different instructions.
Does a CO alarm replace a gas safety certificate or boiler service?
No. A CO alarm provides warning; it does not prove that an appliance, flue or installation is safe. Landlord gas-safety checks, appliance servicing, correct installation and repair remain separate. Gas work must be carried out by a Gas Safe registered engineer where the law requires it.
What happens during a CO alarm visit?
The agreed visit can include recording visible alarm positions, device condition, expiry information, power type and test-button response. Installation, replacement, mains wiring, appliance work or gas-safety checks are completed only where they form part of the confirmed quotation.
What should I send before booking?
Send the full postcode, property type, rooms containing boilers, fires, stoves or other combustion appliances, existing CO alarm details, photographs where useful, access arrangements and deadline. Mention any landlord, HMO, insurer, fire-risk-assessment or local authority requirement.
Are carbon monoxide alarm rules the same across the UK?
No. England, Wales, Scotland and Northern Ireland have different housing and building requirements. This service page focuses on properties in England. Wales requires working CO alarms in rooms containing specified gas, oil or solid-fuel appliances, while Scotland has separate standards for homes with carbon-fuelled appliances. Confirm the property location before booking.
Request a CO alarm quote
Send the postcode, appliance rooms, existing alarms and deadline
We will confirm the suitable alarm service, starting price, access needs and whether gas safety, boiler servicing, smoke alarms or specialist warnings need separate consideration.
