Apex London Spec

Interlinked Smoke Alarm Systems

We design and install interlinked smoke alarm systems to BS 5839-6 for London rentals and HMOs: Grade D1 mains-powered alarms with sealed battery backup, heat alarms in kitchens and CO alarms where combustion appliances sit. Every system is certificated, meeting the 2022 regulations and borough licensing conditions.

Written Guarantee: 5 Years

Average Timeline Range: 1 - 2 days

Grades, and What Landlords Actually Need

BS 5839-6 grades domestic alarm systems by power supply and resilience. Grade D1 — mains-powered alarms with a sealed, tamper-proof ten-year backup battery — is the standard specification for rented property and the one London HMO licensing conditions overwhelmingly require. Grade D2 (replaceable backup batteries) and battery-only Grade F systems sit below it; Grade A panel systems sit above, appearing in larger HMOs and communal areas. We install Grade D1 as our default for landlords because it removes the failure mode councils see most: dead or removed batteries. Once interlinked, every alarm sounds when any alarm triggers — the feature that gets a sleeping tenant on the top floor out when something ignites in the basement kitchen.

LD1, LD2 and LD3 Coverage Levels

The same standard defines how much of the dwelling the system watches. LD3 covers escape routes only — hallways and landings — and is the minimum for ordinary rentals. LD2 adds detection in high-risk rooms: a heat alarm in the kitchen, plus the living room and any room where a fire is likely to start. LD1 covers virtually every room and is specified for higher-risk HMOs. Most London boroughs require at least LD2 coverage with Grade D1 alarms in licensed HMOs, with a heat alarm rather than a smoke alarm in the kitchen to avoid constant false alarms. We confirm the coverage level your licence conditions or fire risk assessment requires, then position alarms where the standard says — on ceilings, clear of corners, walls and light fittings.

The 2022 Regulations and CO Alarms

The Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022 require private landlords in England to provide at least one smoke alarm on every storey used as living accommodation, and a carbon monoxide alarm in any room with a fixed combustion appliance — gas boilers, fires and wood burners, with gas cookers excluded. Landlords must also repair or replace any alarm reported faulty as soon as reasonably practicable. Local authorities can fine up to £5,000 per breach. We fit CO alarms to BS EN 50291 alongside the smoke system, positioned correctly relative to the appliance, and record every device — type, location, serial number and test result — in a certificate your agent can file against the tenancy.

Radio-Interlinked or Wired?

Interlinking can run through a wired interconnect cable or by radio frequency between alarms. In a property already open for refurbishment, wiring the interconnect costs little and is bulletproof. In an occupied or recently decorated rental, radio-interlinked Grade D1 alarms avoid chasing cables through finished walls — each alarm still takes mains power locally, and the link is paired wirelessly. We fit both, choosing per property rather than per habit. Either way the installation is carried out by our NICEIC-registered electricians, new circuits are certificated to BS 7671, and we leave the system tested with every alarm triggering every other — the check that matters, and the one we photograph for the file.

Certified Technology & Material Specifications

To maintain our Renowise prestige guarantee levels, our regional surveyor vans carry specialized heavy-duty diagnostic rigs and certified premium hardware.

PREMIUM COPPER CORE JOINTS, UL-CERTIFIED CIRCUIT RELAYS, INDUSTRIAL GRADE SEALENTS

Frequently Asked Questions (FAQ)

How much does interlinked smoke alarm installation cost in London?

Typically £80–£150 per Grade D1 alarm installed, depending on access and whether suitable wiring already exists. A typical three-storey HMO system — smoke alarms to landings and bedrooms, a heat alarm to the kitchen and CO alarms to appliance rooms — usually lands between £600 and £1,500 fully certificated.

What do the 2022 alarm regulations require of landlords?

The Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022 require a smoke alarm on every storey with living accommodation and a CO alarm in every room with a fixed combustion appliance (gas cookers excluded), working at the start of each tenancy and repaired or replaced promptly when reported faulty. Fines run to £5,000 per breach. HMO licensing typically demands more — usually a full Grade D1 interlinked system.

Do I need a heat alarm in the kitchen?

For LD2 coverage and in licensed HMOs, yes — a heat alarm rather than a smoke alarm, because cooking triggers constant false alarms on smoke sensors and tenants respond by removing them. The heat alarm interlinks with the rest of the system so the whole property still sounds together.

Are radio-interlinked alarms acceptable for HMO licensing?

Yes — BS 5839-6 permits radio interlinking, and councils accept radio-linked Grade D1 systems, which still take mains power at each alarm. They are usually the right answer in occupied or freshly decorated properties, where chasing interconnect cables through finished walls would mean redecorating every room.