Interlinked Smoke Alarms in London: A Complete Landlord Guide to 2022 Regulations

What Changed in October 2022

The Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022 came into force on 1 October 2022, tightening the rules first introduced in 2015. All private landlords in England must now install a smoke alarm on every storey used as living accommodation, not just the principal storey. Carbon monoxide alarms became mandatory in any room containing a fixed combustion appliance — including gas boilers, not just solid fuel appliances as before.

Failure to comply can result in a remedial notice from the local authority and a civil penalty of up to £5,000.

What "Interlinked" Actually Means

Interlinked alarms communicate with each other so that when one detects smoke or CO, every alarm in the property sounds simultaneously. This gives occupants the maximum warning time regardless of where the fire starts. In a three-storey London terrace, a fire starting in the basement kitchen will trigger alarms on every floor at the same moment.

Interlinking is not yet a legal requirement for all private rented properties in England under the 2022 regulations — the current legal baseline requires a working alarm on each storey. However, BS 5839-6:2019 (the British Standard for fire detection in dwellings) recommends interlinking as best practice, and interlinked systems are mandatory in Scotland under the Tolerable Standard 2022 changes.

For HMOs and higher-risk properties, local authorities in London frequently specify interlinked systems as a licence condition.

Wireless Interlinked Systems vs Hard-Wired

Hard-wired interlinked alarms are connected to the mains and communicate via a physical cable loom. They are standard in new-build properties and major refurbishments. Battery backup is built in, so they continue functioning in a power cut. Retrofitting hard-wired interlinking into an existing London period property typically involves lifting floorboards and chasing cables, which is disruptive and expensive.

Radio-frequency (RF) wireless interlinked alarms communicate via a dedicated radio signal rather than cables. Each unit is mains-powered or battery-powered, and they pair together during installation. There is no cable loom to run between rooms. For landlords retrofitting interlinking into a furnished Victorian flat without wanting to disturb decorations, wireless systems are the practical choice.

RF systems must use a dedicated frequency (typically 868 MHz in compliant UK products) to avoid interference from Wi-Fi or other household devices. Look for units meeting EN 54-25 or carrying a recognised third-party certification mark.

BS 5839-6 and Alarm Positioning

BS 5839-6:2019 is the British Standard that governs fire detection and alarm systems in dwellings. It classifies systems by Grade (the technology) and Category (the coverage). For rented properties, a Grade D Category LD2 system is the minimum recommendation for most standard dwellings — this means battery or mains-powered self-contained alarms covering escape routes and high-risk rooms.

Positioning rules under BS 5839-6 include:

• Smoke alarms should be positioned on the ceiling, at least 300 mm from any wall or light fitting.
• In a room or on a landing, the alarm should be within 7.5 m of any sleeping area door or room door off the escape route.
• Heat alarms (not smoke alarms) should be used in kitchens to avoid nuisance alarms from cooking — a smoke alarm directly above a hob will trigger constantly.
• CO alarms should be positioned on a wall or ceiling within 1–3 metres horizontally of the fuel-burning appliance, at approximately head height when standing.
• Avoid positioning smoke alarms within 300 mm of a ventilation duct or air-conditioning outlet.

Where Alarms Must Go Under the 2022 Regulations

The legal minimum for private rented properties in England from October 2022:

• A smoke alarm on every storey of the property that contains a room used as living accommodation (this includes a landing if it is used as a living space).
• A carbon monoxide alarm in every room containing a fixed combustion appliance — this now includes gas boilers. A boiler cupboard counts as a room for this purpose.
• Alarms must be in working order at the start of each new tenancy.

Note that the regulations do not specify alarm type (optical, ionisation, heat) — that is governed by BS 5839-6 best practice. Most installers now default to optical smoke alarms for living areas and landings, heat alarms for kitchens, and electrochemical CO alarms for boiler rooms and reception rooms with gas fires.

Landlord Responsibilities After Installation

Landlords must test alarms at the start of each new tenancy and repair or replace any faulty alarm promptly after being informed by the tenant. Day-to-day battery replacement and testing during the tenancy is considered the tenant's responsibility, but landlords should include a clause in the tenancy agreement making this clear and confirm it in the check-in inventory.

For HMO properties, an annual alarm test log is typically required as part of the licensing regime. Interlinked systems should be tested by triggering one alarm and confirming that all others sound — not just testing each unit individually.