Smoke Alarm Installation Costs UK — What to Charge to Fit Mains and Interlinked Alarms in 2026

Types of Smoke Alarm Job and What to Charge

Not all alarm jobs are the same. A like-for-like swap on an existing mains circuit is a 30-minute task; a brand-new interlinked system across a three-storey house with chasing and replastering is the best part of a day. Here's a breakdown of the common job types with current UK price ranges, supplied and fitted.

Single Mains-Wired Smoke Alarm

The most common standalone job is supplying and fitting one mains-wired alarm — typically a Grade D unit with battery backup on an existing or new spur. If there is already cabling in place (a replacement on a like-for-like base), this is fast work and you're mostly charging for the unit, your time and a call-out minimum.

Where there's no existing cable, you're running a fused spur or extending a lighting circuit, which adds time and materials. Be clear in your quote whether the price assumes existing wiring or a new feed.

• Supplied and fitted, existing cabling: £80–£120
• Supplied and fitted, new spur required: £120–£150+
• Alarm unit only (sealed 10-year vs replaceable battery): £20–£60

Interlinked Mains System — Typical 3-Bed House

Interlinking is where the real value sits. When one alarm triggers, they all sound — essential for giving occupants time to escape from another floor. A typical three-bed house needs alarms on each escape route (hallway and landing), often a smoke or optical alarm in the living room, and a heat alarm in the kitchen (smoke alarms are unsuitable there because of cooking fumes). That's commonly two to three smoke/optical alarms plus one heat alarm.

These can be hard-wired interlinked (a single interconnect cable run between every unit) or radio (RF) interlinked, where the alarms talk to each other wirelessly and only need a local power feed. Hard-wiring gives the cleanest result but means more cabling, chasing and making good. Radio interlinking is faster to install in an occupied or finished house because you avoid pulling interconnect cable between floors.

• 3-bed interlinked system, supplied and fitted: £300–£600
• Larger or three-storey property (4–6 units): £500–£900+
• Heat alarm for the kitchen (unit): £25–£60

Price toward the top of the range where the property is occupied and finished (more care needed making good), where access between floors is awkward, or where the customer wants premium units with smartphone connectivity.

Battery / RF Radio-Interlinked Alarms (No Cabling)

Sealed-battery radio-interlinked alarms are the fastest route to compliance in a finished home, and they're the standard answer for retrofits where running new cable would be disruptive or expensive. The units are pricier than basic mains alarms, but you save hours of cabling and chasing labour, and there's little or no making good.

They're especially relevant for Scotland's interlinked alarm law and for landlords who need a compliant system quickly across multiple rooms without rewiring. The trade-off is the sealed 10-year battery: the whole unit is replaced at end of life rather than swapping a cell.

• Sealed-battery RF interlinked smoke alarm (unit): £30–£60
• Typical 3-bed RF system, supplied and fitted: £250–£450

Cabling, Chasing and Making Good

The single biggest variable on a mains alarm job is whether you're working with existing cabling or installing fresh. Running new cable through a finished house — lifting carpets, drilling between joists, chasing plaster to bury cable in walls — is where the hours add up, and where electricians who quote a flat "per alarm" price get caught out.

Chasing walls means cutting channels, fixing cable, replastering and leaving a wall ready for the customer to redecorate. Some electricians make good to a plastered finish; others leave it filled and flush for the customer's decorator. Be explicit about which you're quoting — "making good" means different things to different people, and it's a common source of disputes.

• Running new cable per alarm (lift floors / chase walls): £40–£100+ per run
• Replastering and making good a chase: extra per channel, by length
• Radio interlinking to avoid interconnect cabling: often quicker and cheaper overall on retrofits

When a job involves significant chasing and making good, quote it as a separate line so the customer sees that the access work — not the alarm hardware — is driving the price. It also protects you if they later say the system "was only a few alarms."

The Regulations Driving the Work

Most alarm enquiries are triggered, directly or indirectly, by regulation. Understanding the framework helps you specify correctly and quote with authority.

Building Regulations & BS 5839-6

In England and Wales, fire detection in dwellings is covered by the Building Regulations — Approved Document B — which references the British Standard BS 5839-6. That standard sets out the grades and categories of system. The most common specification for a typical home is Grade D: mains-powered alarms each with an integral battery backup, interlinked so they all sound together. The category (for example LD2 or LD3) defines which areas need coverage — escape routes plus, in higher categories, rooms with a significant fire risk.

New builds and material alterations must meet the current standard. For existing homes, the standard is the benchmark that landlords, insurers and surveyors increasingly expect.

Scotland's Interlinked Alarm Law

Since February 2022, Scotland has required every home — owner-occupied as well as rented — to have interlinked alarms. The standard specification is a smoke alarm in the living room and on each circulation space (hallways and landings), plus a heat alarm in the kitchen, all interlinked, along with a carbon monoxide alarm where there's a fixed combustion appliance. Alarms can be sealed-battery (tamper-proof, 10-year) and radio-interlinked, or mains-wired and interlinked. This law continues to drive steady demand for retrofit interlinked systems north of the border.

Landlord Duties

In England, the Smoke and Carbon Monoxide Alarm (England) Regulations require at least one smoke alarm on every storey of a rented home used as living accommodation, and a carbon monoxide alarm in any room with a fixed combustion appliance (excluding gas cookers). The rules were extended to cover social housing and tightened the CO requirement. Welsh and Scottish rules go further on interlinking. HMOs (houses in multiple occupation) typically need a higher-category system — often a Grade A or Grade D LD2 design with more coverage — and these are a profitable niche if you understand the licensing requirements.

What Affects the Price

Getting your quote right means pricing the specifics of the property, not a generic "per alarm" rate. The main variables are:

• Number of alarms: The headline driver. A two-storey 3-bed needs fewer units than a three-storey townhouse with a converted loft.
• Hard-wired vs radio-interlinked: Hard-wiring means more cable, chasing and making good; radio interlinking trades pricier units for far less labour.
• Access and chasing: Finished, occupied, carpeted homes are slower and need more care than a property mid-refurbishment with floors up.
• Heat alarm in the kitchen: Almost always required as part of a compliant system — don't forget to include it.
• CO alarms: Needed where there's a fixed combustion appliance (boiler, gas fire, wood burner). Often bundled into the same visit.
• Making good: Whether you leave a flush-filled chase or a fully plastered, decoration-ready finish materially changes your time.

Supply-and-Fit vs Labour-Only

Most customers want a single supplied-and-fitted price, and that's where you make margin on the hardware as well as the labour. Buying alarm units at trade prices and charging a fair retail mark-up is legitimate and expected — the customer is paying for your specification expertise and your guarantee on the install.

Labour-only is occasionally requested where a landlord or builder has already bought the units in bulk. In that case, price your time honestly and add a line for any consumables (cable, fixings, fused spur, replastering materials). Be wary of fitting units the customer supplied that don't meet the standard — you're still responsible for certifying a compliant installation, so specify what's acceptable before you agree.

Day Rate vs Fixed Quoting

For a single alarm or a quick swap, a fixed price with a call-out minimum is the right approach — customers want certainty and the job is too small to meter by the hour. For a full interlinked system with significant cabling, you can price either way.

A typical electrician day rate sits around £200–£300 per day in 2026, higher in London and the South East. A standard 3-bed interlinked retrofit is usually a half to full day for one electrician depending on cabling. The risk with a fixed quote is that you underestimate the chasing; the risk with a day rate is that the customer feels exposed to open-ended cost. The pragmatic answer for bigger jobs is a fixed quote built off a proper survey, with a clearly stated assumption (for example "price assumes radio interlinking; hard-wired interconnect quoted separately").

Quoting Tips — What to Check Before You Price

Alarm quotes go wrong when the electrician prices off the customer's description rather than a proper look at the property. Before you commit a price, check the following:

• Existing cabling: Is there a live mains feed at each alarm position, or are you running new cable? This is the single biggest cost swing.
• Number of storeys and rooms: Count the alarms required against the relevant standard or category before you quote.
• Kitchen heat alarm and CO needs: Identify combustion appliances and confirm a heat alarm is included.
• Access and disruption: Occupied, carpeted, finished homes take longer and need more making good than a refurb.
• Hard-wired vs radio: Confirm the customer's preference and price the cabling implications honestly.
• Certification: You're certifying a compliant system — make sure the spec meets BS 5839-6 / the relevant national rules and that you'll issue the appropriate certificate.

Include a short note in your quote setting out the spec — number and type of alarms, interlink method, kitchen heat alarm, CO coverage and what "making good" means. A one-line spec summary elevates your quote above competitors who just send a number, and it protects you from scope creep.

Landlord and HMO Packages

Landlords are repeat, low-hassle customers who value a single compliant package and a certificate they can show a letting agent or council. Offer a fixed "landlord compliance" price covering interlinked smoke alarms on each storey, a kitchen heat alarm and CO alarms where required, with certification. For HMOs, the category is higher and the system more involved — price these as a survey-led quote, not a flat rate, but build a reputation for getting them signed off first time and the referrals follow.

Quick Reference: Smoke Alarm Installation Prices UK 2026