A working alarm is the cheapest life-saving device you will ever buy, and the standard for what counts as adequate has moved on from a single battery smoke alarm on the landing. Modern domestic systems use mains-powered detectors with battery backup, interlinked so that a fire detected in the kitchen sounds every alarm in the house, including the one outside the bedroom where someone is asleep.
The relevant standard for homes is BS 5839-6, which grades systems by how they are powered (Grade D1, mains with sealed battery backup, is the usual domestic specification) and categorises them by coverage: LD3 covers escape routes only, LD2 adds high-risk rooms such as kitchens and living rooms, and LD1 covers almost every room.
We design and install domestic fire detection across Greater London: houses, flats, rental properties and small HMOs. That includes new interlinked systems, replacing expired detectors, and radio-linked systems that avoid running cables through finished decoration.
What's included
A system designed to BS 5839-6
We assess the property and agree the right grade and category with you, rather than just screwing a detector wherever there happens to be a ceiling rose. For most homes that means Grade D1 detectors in an LD2 layout: escape routes plus kitchen and principal living room.
The right detector in the right room
Optical smoke detectors in hallways and living spaces, heat detectors in kitchens (where a smoke head would false-alarm every time you cook), and carbon monoxide detectors where boilers, gas fires or stoves require them.
Mains-powered, interlinked installation
Detectors wired on a dedicated or lighting-derived supply with battery backup, interlinked by cable or radio so every alarm sounds together. Radio-interlinked mains detectors save decoration in finished homes.
Landlord and HMO compliance
Systems specified to satisfy the Smoke and Carbon Monoxide Alarm (England) Regulations 2022 and, for licensed HMOs, the conditions your local authority attaches, which in London often means a higher category of coverage.
Testing, certification and a maintenance plan
Every system is tested on completion, you get certification for the installation, and we show you the test routine and what the different beeps mean before we leave.
How the job runs
- 1
Property assessment
Tell us the property type, storeys, and whether it is owner-occupied, rented or an HMO. Floor plans or a video walkthrough are usually enough to design the system and price it.
- 2
System design and quote
You get a written specification (grade, category, detector types and positions) and a fixed price, with the reasoning explained so you can see why each detector is where it is.
- 3
Installation
Most homes are completed in half a day to a day. Wired interlinks involve some cable routing and making good; radio-interlinked systems are quicker and kinder to decoration; we recommend whichever suits the property.
- 4
Testing and commissioning
Every detector is tested, the interlink is verified end to end (the kitchen heat detector really does sound the bedroom alarm), and mains and backup supplies are confirmed.
- 5
Handover and paperwork
You receive certification for the system, detector expiry dates are recorded, and landlords get the documentation their compliance file and letting agent will ask for.
What it costs
Fire alarm work starts from £120, which covers small jobs such as replacing an expired mains detector like for like. A complete interlinked system for a typical London home comes in between £150 and £500 depending on the number of detectors, whether interlinking is wired or radio, and how much cable routing and making good the property needs.
Radio-interlinked detectors cost more per unit but install faster with no damage to decoration, so the totals often land close together; we price both where it is a genuine choice. Detector count is set by the property, not by upselling: an LD2 system for a two-storey house is typically four to six detectors. Prices are confirmed in writing before installation.