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Letting Agent Today12 November 2025High risk

Carbon Monoxide Alarms: A ‘Silent Killer’ Every London Landlord Must Manage Now

Landlords and agents in England face strict legal duties to install and maintain carbon monoxide (CO) alarms in rental properties with fuel-burning appliances. This article explains these obligations, practical steps for compliance, and how to protect tenants from this high-risk hazard.

carbon monoxidecarbon monoxide alarmslandlord compliancegas safetyrental property safetytenant safety

Why Carbon Monoxide Safety Is a Top Priority for Landlords

Carbon monoxide (CO) poisoning remains a serious but often overlooked risk in private rental properties. Known as the ‘silent killer’ because it is colourless and odourless, CO can cause fatal poisoning if undetected. Propertymark has issued urgent warnings for landlords and letting agents to prioritise CO safety following legal requirements in England.

The Legal Landscape: What Landlords Must Do

Since 1 October 2015, landlords in England are legally required to install carbon monoxide alarms in every room containing a fixed combustion appliance — including boilers, gas fires, and cookers. The key obligations include:

  • Installation: At least one working CO alarm must be installed in each room with a fuel-burning appliance before a new tenancy starts.
  • Testing: Alarms must be tested and confirmed working at the start of each tenancy.
  • Gas Safety Checks: Annual gas safety inspections must be carried out by Gas Safe registered engineers, with valid Gas Safety Certificates provided to tenants within 28 days.
  • Maintenance: Managing agents must ensure CO alarms and gas appliances are regularly maintained and safety checks documented.

Failure to comply can lead to enforcement action, fines, or worse — serious injury or death.

Practical Steps Landlords Can Take Immediately

1. Audit Your Properties: Identify all rooms with fuel-burning appliances across your portfolio. Single-unit landlords should focus on their single property; portfolio landlords and HMO operators must be systematic to cover multiple units.

2. Install CO Alarms if Missing: Purchase alarms certified to British Standards (BS EN 50291) and install them correctly. For HMOs, ensure alarms are installed in each relevant room, not just communal areas.

3. Schedule Alarm Testing at Tenancy Start: Incorporate alarm testing into your pre-tenancy checklist. Document the test results and keep records for compliance evidence.

4. Arrange Annual Gas Servicing: Book Gas Safe registered engineers to service all boilers, fires, and cookers annually. Confirm this includes appliance safety and CO risk checks.

5. Provide Gas Safety Certificates to Tenants Promptly: Within 28 days of inspection, deliver certificates electronically or in hard copy. This is a legal right for tenants and a compliance must.

6. Engage Tenants: Inform tenants about the importance of:

  • Testing alarms monthly themselves
  • Keeping ventilation vents clear
  • Reporting alarms or appliance faults immediately

Consider sending a tenant newsletter or text reminders, especially during colder months.

Managing Agents’ Role in Compliance

If you manage properties on behalf of landlords, ensure your processes:

  • Include CO alarm installation and testing in the property onboarding and tenancy renewal workflows
  • Document and store evidence of all safety checks and maintenance
  • Communicate tenant responsibilities clearly

This proactive approach reduces risk and demonstrates professionalism.

Using Carbon Monoxide Awareness Week (17–23 November)

This annual safety campaign presents a timely opportunity to review procedures and raise tenant awareness. Landlords and agents should:

  • Remind tenants to test alarms monthly
  • Confirm all alarms are operational
  • Review servicing schedules

Different Landlord Profiles: Tailored Considerations

  • Single-Unit Landlords: Likely to manage safety checks personally; focus on clear record-keeping.
  • Portfolio Landlords: Implement systematic audit and maintenance schedules; consider software tools for compliance tracking.
  • HMO Operators: Pay close attention to multiple alarms and ensure all communal and private rooms with fuel-burning appliances are covered.
  • Accidental Landlords: May need professional help to identify and manage risks — consider engaging a managing agent or compliance expert.

Next Steps: Your Compliance Workflow for the Coming Weeks

  1. Conduct a full property safety audit — identify CO alarm needs and appliance servicing dates.
  2. Install or replace CO alarms where missing or expired.
  3. Schedule annual gas safety inspections with Gas Safe engineers immediately.
  4. Update tenancy agreements and check-in procedures to document alarm testing.
  5. Communicate clearly with tenants about their role in maintaining safety.
  6. Prepare for Carbon Monoxide Awareness Week communications and reminders.

How Rentals & Sales Can Support You

Our landlord intelligence team offers tailored services including portfolio compliance audits, gas safety review, and pricing strategy advice aligned with safety investment. We help you build robust workflows that protect tenants and your investment.

Contact us to arrange a compliance review or operational consultation.

Compliance Disclaimer: This article is for informational purposes and does not constitute legal advice. Landlords should consult official guidance and qualified professionals to ensure full compliance with current regulations.