The Short Answer
On our estimates, mains-wired smoke alarms cost about £75 to £150 each fitted. Three or four interlinked alarms in a typical house are £250 to £500, and battery alarms fitted £40 to £75. A basic three-alarm system is about half a day's work.
Interlinked alarms are worth it: when one goes off, they all do, so you hear a fire on another floor. Landlords in England must have smoke alarms on every storey and carbon monoxide alarms where there's a fixed combustion appliance.
Smoke and fire alarm prices
| Item | Typical cost |
|---|---|
| Battery alarm, fitted | £40 to £75 |
| Mains-wired alarm, each, fitted | £75 to £150 |
| Typical house: 3 to 4 interlinked alarms | £250 to £500 |
Which alarms where?
- Interlinked: when one alarm triggers, they all sound. That matters most in a house on more than one floor. Wired systems link by cable; wireless ones by radio, which is quicker and less disruptive in an existing home.
- Heat alarms respond to heat, not smoke or steam, so they suit kitchens and garages where a smoke alarm would keep going off. They only trigger once a fire is established, so they shouldn't be your only alarm.
- Mains-powered alarms need wiring in, so use an electrician; battery alarms are easy to fit yourself.
Free alarms from the fire service
Before you pay, check whether you qualify for a free home safety visit from your local fire and rescue service. They're aimed at people at higher risk, and the service decides who's eligible, usually through a short online check or a phone call. In Wales, the Welsh Government says a visit includes free advice and equipment, with smoke and carbon monoxide alarms provided if needed. Greater Manchester's free Home Fire Safety Assessment gives advice and equipment depending on risk. Search for your own fire service's page to see what it offers.
Alarms for landlords
In England, a landlord must:
- fit a smoke alarm on every storey with a room used as living accommodation;
- fit a carbon monoxide alarm in any room used as living accommodation with a fixed combustion appliance (a boiler, fire or stove), except gas cookers;
- check they work on the day a new tenancy starts, and repair or replace any reported faulty.
The council can charge a penalty of up to £5,000.
Certificates
Mains alarms added to an existing circuit aren't notifiable in England; a new circuit is. A new circuit, a new consumer unit, or work in a bathroom's special location is notifiable: use an electrician registered with Blue Flame, Certsure (NICEIC and ELECSA), NAPIT or OFTEC, who certifies it, or tell building control. See what you should get at the end.
Get fire alarm system quotes
Alarms are priced per alarm, and by whether they're mains-wired and linked.
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Frequently asked questions
Does the fire brigade fit smoke alarms for free?
Often, if you're at higher risk. Fire and rescue services offer free home safety visits to people who need them, and fit smoke alarms (and in Wales carbon monoxide alarms) where needed. Each service decides who qualifies, so check with yours.
How much does it cost to install smoke alarms?
On our estimates, about £75 to £150 each for mains-wired alarms, or £250 to £500 for three or four interlinked alarms in a typical house.
How much would an electrician charge to install smoke detectors?
About £75 to £150 per mains alarm on our estimates, less per alarm when several go in at once.
Do landlords have to fit smoke alarms?
Yes, in England: one on every storey with living accommodation, plus carbon monoxide alarms where there's a fixed combustion appliance other than a gas cooker. Penalties reach £5,000.
Do I need a carbon monoxide alarm?
The law requires landlords to fit them in rooms with a fixed combustion appliance (not gas cookers). I'd fit one in any room with a boiler, fire or stove, even where the law doesn't require it.
Are linked smoke alarms worth it?
Yes: when one detects smoke, they all sound, so you hear a fire on another floor.
How we priced thisView sources (5, 5 official)
Rules come from the legislation and official guidance, read at source. Prices are our estimates: we check them against trade price data, retailer shelf prices and specialists' price lists, then build them up from their parts so the totals add up. Below are the sources behind the page; the trade price guides we only compare against aren’t listed. Where sources disagreed, we've said so. More on our method.
- OfficialGet a free home safety check from your local fire and rescue service, Welsh Government (GOV.WALES). Checked 16 Oct 2026.
- OfficialHome Fire Safety Assessments, Greater Manchester Fire and Rescue Service. Checked 16 Oct 2026.
- OfficialThe Smoke and Carbon Monoxide Alarm (England) Regulations 2015, regulations 4 and 8, legislation.gov.uk. Checked 15 Oct 2026.
- OfficialThe Building Regulations 2010, regulation 12(6A) and (9): notifiable electrical work and 'special location' (England), legislation.gov.uk. Checked 14 Oct 2026.
- OfficialThe Building Regulations 2010, Schedule 3: self-certification schemes (para 16, roof coverings), legislation.gov.uk. Checked 15 Oct 2026.
