Carbon monoxide alarm requirements
A CO alarm is required in every room with a fixed combustion appliance other than a gas cooker.
5 min read · Updated 2 August 2026
Overview
Since 1 October 2022, landlords in England must fit a carbon monoxide alarm in any room used as living accommodation that contains a fixed combustion appliance — gas boilers, gas fires, wood burners, oil boilers — excluding gas cookers. The alarm must be tested and working on the first day of the tenancy.
Why it matters
Carbon monoxide is undetectable without an alarm and kills. Enforcement mirrors smoke alarms: a remedial notice and a penalty of up to £5,000 per breach.
Legal requirements
- Fit a CO alarm in every room containing a fixed combustion appliance (excluding gas cookers).
- Test the alarm on the first day of the tenancy and record the result.
- Repair or replace faulty alarms as soon as reasonably practicable after a report.
- Coverage extends to social housing and applies regardless of fuel type.
Common mistakes
- Fitting a CO alarm only near the boiler and missing a wood burner in the lounge.
- Positioning the alarm incorrectly — follow the manufacturer's height and distance instructions.
- Assuming the annual gas safety check covers CO alarm duties; it does not.
- Letting a 7-year sensor expire without replacement.
Practical guidance
- Record the alarm expiry date alongside the gas safety renewal date.
- Photograph the alarm and its position at each inspection.
- Combine CO alarm checks with the gas safety visit to reduce access requests.
- Give tenants a short written note on what to do if the alarm sounds.
Frequently asked questions
Which rooms need a CO alarm?
Every room used as living accommodation that contains a fixed combustion appliance, excluding gas cookers.
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This guide is general information for UK landlords and letting agents, not legal advice. Rules differ across England, Wales, Scotland and Northern Ireland — check your local requirements or take advice before acting.