Carbon Monoxide Alarm Regulations: What Landlords Must Provide

Carbon monoxide is odourless, colourless, and lethal. Every year in the UK, accidental carbon monoxide poisoning causes around 60 deaths and leads to thousands of hospital admissions. In rental properties, where tenants rely on the landlord to maintain gas appliances and heating systems, the risk is real and the legal obligations are clear.

For landlords in Middlesbrough and across Teesside, the carbon monoxide alarm regulations have been strengthened in recent years. Getting them wrong is not just a compliance risk — it is a safety issue that could have devastating consequences. Here is exactly what the law requires and what you need to do.

The Current Legal Requirements

The Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022 expanded the requirements significantly. Prior to the amendment, carbon monoxide alarms were only required in rooms containing a solid fuel burning appliance (such as a wood burner or open fire). The updated regulations extend this to all rooms containing a fixed combustion appliance — which includes gas boilers, gas fires, and oil-fired heating systems.

In practical terms, for most rental properties in Middlesbrough, this means:

A carbon monoxide alarm must be installed in any room that contains a gas boiler. This is the most common requirement. If the boiler is in the kitchen, a CO alarm must be in the kitchen. If it is in a utility room, the alarm goes in the utility room.

A carbon monoxide alarm must be in any room with a gas fire. Many older Middlesbrough terraces and semis still have gas fires in the living room. Each of these rooms needs its own CO alarm.

A carbon monoxide alarm must be in any room with an oil-fired appliance. Less common in urban Middlesbrough but relevant for some properties on the outskirts of Teesside.

A carbon monoxide alarm must be in any room with a solid fuel appliance. Wood burners, open fires, and multi-fuel stoves all require a CO alarm in the same room.

The key change in 2022 was the inclusion of gas appliances. Previously, a landlord with a gas boiler in the kitchen and no solid fuel appliances could legally have no CO alarms in the property at all. That is no longer the case.

What Type of Alarm Do You Need

The regulations specify that carbon monoxide alarms must comply with British Standard EN 50291. When purchasing alarms, look for this standard printed on the packaging or the alarm itself.

You have two main options:

Battery-powered alarms. These are the simplest and cheapest option, typically costing £15 to £25 each. Sealed lithium battery units with a ten-year lifespan are the best choice — they require no battery changes during their lifetime and provide reliable protection. Avoid cheap alarms with replaceable AA batteries, which tenants may remove and not replace.

Mains-wired alarms. These are wired into the property's electrical system, often with a battery backup. They are more expensive to install (typically £60 to £100 per unit including fitting by an electrician) but provide permanent, always-on protection. If you are renovating a property or having electrical work done, mains-wired alarms are worth considering.

Both types are compliant with the regulations. The important thing is that the alarm meets EN 50291 and is positioned correctly.

Where to Position CO Alarms

Correct positioning is essential. A carbon monoxide alarm in the wrong location may not detect a leak quickly enough to protect the occupants.

Height: Carbon monoxide mixes with air and does not rise or fall predictably like smoke. CO alarms can be wall-mounted at head height (approximately 1.5 metres from the floor) or ceiling-mounted. Follow the manufacturer's specific instructions.

Distance from the appliance: The alarm should be in the same room as the combustion appliance, between one and three metres from the appliance where possible. Do not mount it directly above or next to the appliance, as heat and steam can cause false alarms.

Avoid these locations: Do not place CO alarms in bathrooms, near windows or doors where drafts could affect detection, directly above cooking hobs, or in enclosed spaces with poor air circulation.

Multiple appliances in different rooms: If your property has a gas boiler in the kitchen and a gas fire in the living room, you need two separate CO alarms — one in each room.

Testing and Maintenance

The regulations require that landlords ensure carbon monoxide alarms are in proper working order at the start of each new tenancy. This means physically testing the alarm — pressing the test button and confirming the alarm sounds — on the day the tenant moves in or during the property check-in.

For existing tenancies, there is no statutory requirement to test alarms at specific intervals, but best practice — and our strong recommendation — is to check all CO alarms during routine property inspections, which should happen at least every six months.

If a tenant reports that a CO alarm is not working, you must replace it promptly. A non-functional alarm is the same as no alarm — and places both the tenant at risk and you in breach of the regulations.

CO alarms have a limited lifespan, typically seven to ten years depending on the model. Check the expiry date printed on the alarm and replace it before it expires. Adding alarm replacement dates to your compliance calendar ensures nothing is missed.

The Penalties for Non-Compliance

Local authorities have the power to issue remedial notices requiring landlords to install CO alarms within 28 days. If you fail to comply with a remedial notice, the local authority can arrange installation themselves and charge you for the cost — plus issue a civil penalty of up to £5,000.

In Middlesbrough, the local authority takes these requirements seriously. Enforcement activity has increased in recent years, and properties inspected as part of licensing applications or complaint investigations are routinely checked for CO alarm compliance.

Beyond the financial penalties, the reputational and moral consequences of a carbon monoxide incident in a property without proper alarms are severe. This is one area of compliance where cutting corners is never worth the risk.

Common Mistakes Landlords Make

Relying on gas safety checks as a substitute. An annual Gas Safety Certificate confirms that your gas appliances are safe at the point of inspection. It does not protect against faults that develop between inspections. CO alarms provide continuous monitoring — they are a separate requirement, not a substitute for gas safety checks.

Installing alarms in hallways instead of the room with the appliance. The alarm must be in the same room as the combustion appliance. A CO alarm in the hallway when the boiler is in the kitchen does not meet the legal requirement.

Forgetting about combination boilers in bedrooms. Some older properties in Middlesbrough have boilers located in airing cupboards within bedrooms. If the boiler is in or opens onto a bedroom, that room needs a CO alarm.

Not checking alarm expiry dates. An expired CO alarm may not detect carbon monoxide reliably, even if it appears to be working when the test button is pressed. The sensor degrades over time, and an alarm past its expiry date is not compliant.

Assuming the tenant will sort it. The legal obligation to provide and test CO alarms sits with the landlord, not the tenant. You cannot delegate this responsibility by asking tenants to buy their own alarms.

Our Recommendation

For any rental property in Middlesbrough or Teesside, we recommend the following as a minimum:

1. A sealed ten-year lithium battery CO alarm in every room containing a combustion appliance
2. A smoke alarm on every storey of the property (separate requirement, equally important)
3. A record of the alarm make, model, installation date, and expiry date in your compliance file
4. Physical testing at the start of every tenancy and at every inspection
5. Proactive replacement before the expiry date

The total cost of equipping a typical Middlesbrough terraced house with a quality CO alarm is £20 to £30. The cost of not having one — in potential fines, legal liability, and human terms — is immeasurably higher.

Talk to Ascot Knight

At Ascot Knight, CO alarm compliance is part of our standard property management service. We ensure every property we manage has the correct alarms in the correct locations, tested and documented. If you are unsure whether your Middlesbrough rental property meets the current requirements, contact us today for a free compliance check.