Here is the short answer: interlinked smoke alarms all sound together — a fire detected in the kitchen wakes you in the bedroom — and that is why regulations increasingly require them. Scotland now requires interlinked alarms in every home; in England and Wales the duties differ by tenure and build type, with landlords carrying specific obligations. You can meet the standard two ways: mains-powered interlinked detectors, or wireless systems — including the Ajax FireProtect 2, which puts smoke and heat detection on the same app as a security alarm with a sealed ten-year battery.
In brief:
- Interlinked means every alarm sounds when one detects — the feature that buys escape time at 3am.
- Scotland: interlinked alarms are required in all homes. England & Wales: requirements vary by tenure and build — landlords especially should check current government guidance.
- Wireless interlinking has removed the rewiring barrier: sealed-battery detectors link by radio, and Ajax puts fire on your security app.
A standalone smoke alarm protects the room it is in. Fires do not stay in the room they start in — and neither does the smoke that kills, which travels faster and quieter than flame. The whole case for interlinking is one sentence: the alarm that matters is the one on the ceiling above your bed, sounding for a fire two floors down.
We have supplied Birmingham's trade with fire detection from Villa Road since 1975, and interlinking has moved from best practice to legal requirement across much of the UK. Here is the honest guide.
What does "interlinked" actually mean?
Linked alarms talk to each other: when one detects smoke or heat, every alarm in the system sounds. Traditionally that meant a mains-wired interconnect cable between ceiling fittings; today it just as often means radio — wireless interlinked detectors that pair to each other, or smart detectors that report through a hub. Same principle either way: one detection, whole-house alarm.
What do the rules require?
Scotland requires interlinked smoke alarms (living room and circulation spaces on every storey) and a heat alarm in the kitchen in every home, with carbon monoxide detection where there is a fixed combustion appliance. England and Wales set duties by situation: new builds and rented homes carry specific requirements — rented homes need working smoke alarms on every storey and CO alarms where required, and building regulations govern new work. The honest advice we give at the counter: if you are a landlord or altering a property, check the current government guidance for your exact case before buying — the rules are periodically updated, and your tenure decides your duties.
Route one: mains interlinked detectors
The traditional gold standard: mains-powered detectors with battery back-up, interlinked by wire or radio module. The Aico Ei3024 is the one we hand across the counter most — a multi-sensor combining optical and heat detection, Ei3000MRF-compatible so it interlinks wirelessly via Aico's SmartLINK module. Mains detection is a fit-and-forget decade of protection; note that new mains fire alarm circuits are notifiable electrical work, so budget for the electrician alongside the detectors.
Route two: fire detection on your security system
The modern alternative: the Ajax FireProtect 2 SB detects both smoke and heat, runs a sealed ten-year battery, and enrols on the same Ajax hub as your intruder alarm — so every FireProtect in the house sounds together, and the alert lands on every phone in the family whether you are upstairs or abroad. For a household already running an Ajax kit, whole-home fire detection becomes an afternoon of ceiling mounts with no wiring at all — and it is the route that also covers the holiday scenario, because a fire alert you cannot hear is still one you receive.
Trade tip: heat detection — not smoke — in the kitchen and garage, where toast and exhaust fumes false-alarm optical sensors into being disabled. A silenced smoke alarm protects nobody; the right sensor type in the right room is what keeps the system switched on. Our heat detector guide covers the split.
Where do the alarms go?
- Every storey: hallway and landing ceilings — the escape route is the priority.
- Living room: required in Scotland, sensible everywhere.
- Kitchen: heat alarm, never optical smoke.
- Garage and loft conversions: the rooms fires start in and detection forgot — our garage guide makes the case.
- CO: any room with a boiler, stove, fire or other fixed combustion appliance.
Interlinked Fire Detection, Summarised
| Route | Power | Best for | WME pick |
|---|---|---|---|
| Mains interlinked | 230V + back-up | New work, rewires, landlord portfolios | Aico Ei3024 |
| Security-system fire | Sealed 10-year battery | Ajax households, no-rewire retrofits, app alerts | Ajax FireProtect 2 SB |
Expert Help in the West Midlands
Villa Road, Birmingham, since 1975. Tell us the property, the tenure and what is already on the ceilings, and we will spec the compliant layout room by room — and tell you plainly which route is cheaper for your house, because the answer genuinely differs between a rewire-anyway renovation and a lived-in semi.
Browse fire safety and detection and the Ajax range. Get in touch for a layout.
Related reading: the best smoke and CO detectors and heat detectors explained.
Frequently Asked Questions
Are interlinked smoke alarms a legal requirement?
In Scotland, yes — every home. In England and Wales the duties depend on tenure and building work: rented homes and new builds carry specific requirements, and landlords should check current government guidance for their exact obligations before buying.
Do interlinked alarms need rewiring?
No longer — wireless interlinked detectors connect by radio, and smart detectors like the Ajax FireProtect 2 SB link through a hub with a sealed ten-year battery. Mains interlinked systems remain the classic route where wiring is already planned.
Can a smoke alarm connect to a burglar alarm?
On systems built for it, yes — Ajax fire detectors enrol on the same hub as the intruder alarm, sound together across the house, and push alerts to every user's phone. One system, one app, both risks covered.