Best Carbon Monoxide Alarms UK (2026): A Landlord’s Buying Guide

Last updated: 4 November 2026

Carbon monoxide (CO) has no smell, colour or taste, and it can kill before anyone in the room notices. Since 1 October 2022, landlords in England have had a legal duty to fit CO alarms in rooms with a fixed combustion appliance. This guide covers what the law requires, how to choose an alarm that suits a rental, three alarms worth buying, where to fit them, and how to keep records that will satisfy a council.

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The law: where landlords must fit CO alarms

The Smoke and Carbon Monoxide Alarm (England) Regulations 2015, as amended from 1 October 2022, require private landlords to:

• fit a carbon monoxide alarm in any room used wholly or partly as living accommodation that contains a fixed combustion appliance, other than a gas cooker;
• fit a smoke alarm on every storey with a room used as living accommodation;
• check all alarms are working on the day each new tenancy starts;
• repair or replace an alarm as soon as reasonably practicable once told it is faulty.

“Living accommodation” includes bathrooms and hallways, not only bedrooms and living rooms. A boiler in a bathroom or a hallway cupboard therefore needs an alarm in that space. The rule covers appliances that burn any fuel: gas, oil, coal or wood. Councils enforce it with a remedial notice, and if you do not comply within 28 days they can fit the alarms themselves and fine you up to £5,000.

For the smoke alarm side, see our smoke and CO alarm regulations guide. Alarms do not replace the annual gas check; our gas safety certificate guide covers that duty.

Does this room need a CO alarm?

✓ Yes

Kitchen with a gas boiler; living room with a gas fire or wood burner; bathroom with a boiler; bedroom with any fuel-burning heater

✗ Not required

Room with only a gas cooker or hob; room with electric heating only

⚠ Good practice

Rooms next to a flue or boiler cupboard; bedrooms above an integral garage; a kitchen with a gas cooker

Based on the Smoke and Carbon Monoxide Alarm (England) Regulations as amended in 2022.

What to look for in a CO alarm for a rental

Feature	What to choose	Why it matters in a rental
Standard	BS EN 50291, ideally with a Kitemark	The benchmark a council or insurer will expect
Power	Sealed 10-year lithium battery	Tenants cannot remove the battery, and you never need to replace it
Sensor life	7 to 10 years, with an end-of-life warning	The sensor wears out; the alarm should tell you when
Display	Optional digital reading	Helps a tenant tell you whether low levels have been detected
Interlinking	Mains-wired or radio-interlinked	Worth it in HMOs and larger houses so an alarm sounds throughout

Battery alarms are allowed under the regulations for both smoke and CO. Mains-wired alarms are required by building regulations when you install a new combustion appliance, such as a replacement boiler, and many HMO licences ask for interlinked systems. Check your licence conditions before you buy. For a whole portfolio, it is usually cheaper to buy sealed 10-year CO alarms in multipacks.

Three carbon monoxide alarms worth buying

Alarm	Best for	Power	Sensor life
Kidde K5CO	Budget pick	Replaceable AA	10 years
FireAngel FA6813	Battery-powered all-rounder	Replaceable AA	Up to 7 years
EITO CO alarm	Cheapest with a digital display	Replaceable AAA	Check the listing

1. Kidde K5CO: best budget CO alarm

A simple, reliable alarm with a 10-year sensor life, powered by replaceable AA batteries, with a loud alarm. If you need a compliant alarm at the lowest sensible price for a single flat, this is a good choice. The trade-off is that a tenant can remove the batteries, so test it at each visit. Check the price of the Kidde K5CO on Amazon.

2. FireAngel FA6813: best battery-powered all-rounder

FireAngel is one of the best-known UK fire safety brands. This alarm meets EN 50291 with a Kitemark, has a loud alarm and LED indicators, and fits on a wall or sits on a shelf in minutes. A dependable choice for most rooms. Check the price of the FireAngel FA6813 on Amazon.

3. EITO CO alarm: cheapest with a digital display

An inexpensive alarm with an LED display showing the CO reading, plus a loud siren. Batteries are usually sold separately. Good value if you want tenants to be able to read the level. Check the listing confirms EN 50291 before you buy. Check the price of the EITO CO alarm on Amazon.

Where to install a CO alarm

Always follow the manufacturer’s instructions. The regulations do not set a position, but the usual guidance is:

• 1 to 3 metres horizontally from the appliance;
• on the ceiling at least 300mm from any wall, or on a wall at least 150mm below the ceiling and higher than any door or window;
• in a bedroom, near the breathing zone of the bed;
• not directly above a cooker or sink, next to an extractor fan, window or vent, in a cupboard, or behind furniture or curtains.

Testing and record-keeping

Councils look for evidence that alarms worked on day one of the tenancy. Keep a simple record for each property:

Record	Example
Location and appliance	Kitchen, next to the gas boiler
Make and model	FireAngel FA6813
Installed and replace-by dates	March 2026, replace by March 2033
Tested at tenancy start	Date, who tested, signed by the tenant on the inventory
Later tests and repairs	Date of each inspection or fault report and what you did

Ask tenants to test alarms monthly with the test button and to tell you immediately if one beeps or fails. Add the alarms to every routine visit; our guide to how often to inspect a rental property covers what else to check.

What tenants should do if the alarm sounds

Put this in your tenant welcome pack or tenant handbook:

1. Open doors and windows, turn off the appliance if it is safe to do so, and get everyone outside into fresh air.
2. Call the National Gas Emergency Service on 0800 111 999.
3. If anyone has headaches, dizziness, nausea, breathlessness or confusion, call 999 or NHS 111.
4. Do not use the appliance again until a Gas Safe registered engineer has checked it.

Written by The Landlords Portal Team and checked against GOV.UK guidance in November 2026. Applies to private rented homes in England. This is general information, not legal advice. Always follow the manufacturer’s instructions.

Frequently asked questions

Are carbon monoxide alarms a legal requirement for landlords?

Yes. Since 1 October 2022, landlords in England must fit a CO alarm in any room used as living accommodation that has a fixed combustion appliance, other than a gas cooker.

Do I need a CO alarm in a kitchen with a gas cooker?

Not for the cooker alone. If the kitchen also has a boiler or another fixed combustion appliance, you do. Many landlords fit one anyway as good practice.

Can I use battery-powered CO alarms?

Yes, the regulations allow battery alarms. Building regulations require a mains-wired alarm when a new combustion appliance is installed, and HMO licences may set their own rules.

Can a smoke alarm detect carbon monoxide?

No. You need a dedicated CO alarm, or a combined unit that clearly states it detects both smoke and carbon monoxide.

How long do CO alarms last?

Usually 7 to 10 years. Replace the whole alarm at the end of its stated sensor life, and record the replace-by date.