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Compliance
Carbon monoxide alarms: the rules, the signs, and what to tell tenants
By Jordan Valentine-Dunn, Gas Safe registered engineer · 9 July 2026
Landlords must fit carbon monoxide alarms, but exactly where differs by nation. In England, an alarm is required in any room used as living accommodation with a fixed combustion appliance (gas cookers excluded). Scotland and Wales have their own, in places stricter, rules. Wherever you let, alarms should be tested and replaced by their end-of-life date.
The rules, nation by nation
England
Since 1 October 2022, a carbon monoxide alarm is required in any room used as living accommodation that contains a fixed combustion appliance, excluding gas cookers. Landlords must repair or replace an alarm once told it's faulty.
Scotland
Since February 2022, a CO alarm is required in any room with a carbon-fuelled appliance or a flue, and the rule applies to every home, not just rentals. Cookers and hobs are excluded.
Wales
Under the Renting Homes fitness rules from December 2022, a CO alarm is required in any room with a gas, oil or solid-fuel appliance, with no exclusion for gas cookers, so Wales goes further than England and Scotland on that point.
The signs of carbon monoxide poisoning
Carbon monoxide is colourless and odourless, so the alarm matters, but so does knowing the symptoms. The NHS lists headache, dizziness, nausea or being sick, tiredness and confusion, stomach pain, and shortness of breath. A telling clue is that symptoms often ease when you leave the building and come back when you return. It's worth passing this to tenants in writing when they move in.
Why winter is the risk season
The danger peaks in the colder months, when appliances run hardest and homes are shut up against the cold. UK health data shows the large majority of accidental carbon monoxide deaths happen in autumn and winter, which is exactly why an annual gas safety check before the heating season, and a working alarm, matter so much.
If an alarm sounds or anyone shows symptoms, treat it as an emergency: get everyone into fresh air, turn the appliance off if you safely can, and call the gas emergency line on 0800 111 999. This is general guidance, not legal advice, and rules differ across the UK nations; only a Gas Safe registered engineer can carry out the gas safety check.