Working alarms give you the early warning you need to get out safely. Here's how to choose the right ones, where to put them and what the rules are across the UK.

Types of Smoke Alarm

  • Ionisation alarms – the older type. They went off all the time with burnt toast and cooking, so many people took the batteries out. They're no longer generally sold.
  • Optical (photoelectric) alarms – detect smoke with a beam of light. They're not usually set off by burnt toast or steam from the shower, and they're good at picking up slow, smouldering fires.
  • Multi-sensor ("double-trigger") alarms – combine smoke and heat sensing, so they only go off when it's likely to be a real fire. Even fewer false alarms.

Fit smoke alarms in hallways, landings, living rooms and bedrooms.

Heat Alarms

Heat alarms go off when the temperature rises quickly. Use them where a smoke alarm would go off too easily, or where there's dust or fumes: kitchens, garages and unoccupied loft spaces.

Carbon Monoxide (CO) Alarms

Carbon monoxide has no colour, taste or smell, so an alarm is the only way to detect it. It's produced when fuel doesn't burn properly – for example, by a faulty boiler, gas fire, wood burner or blocked flue. Every year, people in the UK die from carbon monoxide poisoning at home.

Fit a CO alarm in any room with a fuel-burning appliance, following the manufacturer's instructions for the exact position. Look for one made to BS EN 50291.

Battery, Mains or Wireless?

  • Sealed long-life battery – a battery that lasts the life of the alarm (often 10 years). Easy to fit yourself, and nobody can borrow the battery for the TV remote.
  • Replaceable battery – the cheapest option, but you need to remember to change the battery. When it runs low, the alarm starts that annoying chirp in the middle of the night – so the battery comes out, and it's easy to forget the alarm no longer has one. Not suitable where the rules ask for sealed or mains alarms.
  • Mains-powered (hard-wired) – connected to the electricity supply by a qualified electrician, with a backup battery so they keep working in a power cut.
  • Wireless interlinked – alarms that talk to each other by radio, so when one goes off, they all do. No wiring between rooms.
  • App-controlled ("smart") alarms – connect to your phone, so you get an alert even when you're out, and can check battery and test status.

Alarms for Deaf and Hard of Hearing People

Special alarm kits use a bright flashing light and a vibrating pad that goes under the pillow, linked to the smoke alarms, so they wake someone who can't hear the alarm. Your local fire and rescue service may be able to help – many offer free home fire safety visits.

Where to Fit Them

  • On the ceiling, ideally near the middle of the room or hallway.
  • Away from walls and light fittings, and a distance from the edge of the ceiling – air doesn't move well in corners, so smoke may not reach the alarm. Check the manufacturer's instructions for the exact distance.
  • Not right at the top of a pointed or sloping ceiling or roof void. A pocket of trapped air there can stop smoke reaching the alarm.
  • Away from kitchens (unless it's a heat alarm), bathrooms, heaters and air vents, where steam, heat or draughts can cause false alarms or stop smoke reaching the alarm.

Testing and Replacing

  • Press the test button regularly – fire services recommend once a month. An easy way to remember is to test them whenever the clocks go forward or back, as well as your monthly check.
  • Replace alarms by the date on the alarm – usually after 10 years. It's not just the battery that fades; the sensor does too.

The Rules Across the UK

The rules on alarms are different in each part of the UK:

  • Scotland – since 1 February 2022, every home must have interlinked alarms: a smoke alarm in the living room and in every hallway and landing, a heat alarm in the kitchen, and a CO alarm where there's a carbon-fuelled appliance such as a boiler or fire. See Fire safety for home owners (mygov.scot).
  • England – landlords (private and social) must fit a smoke alarm on every storey used as living accommodation, and a CO alarm in any room with a fixed combustion appliance (except gas cookers). See Smoke and carbon monoxide alarm guidance (GOV.UK).
  • Wales – landlords must fit a mains-powered, interlinked smoke alarm on every storey, and a CO alarm in any room with a gas, oil or solid fuel appliance they've installed. See Fitness for human habitation guidance (GOV.WALES).
  • Northern Ireland – private landlords must fit interlinked alarms: a smoke alarm in the main living room and every hallway and landing, a heat alarm in the kitchen, and a CO alarm wherever there's a fixed combustion appliance or flue. See New alarm requirements for private rentals (Department for Communities).

Businesses, houses in multiple occupation (HMOs) and holiday lets have their own requirements, set by their fire risk assessment.

Worth remembering… your fire risk assessment is what decides the equipment your premises need. This guide is general advice, not a substitute for it.

Not sure what you need? Get in touch with our team – we'll be delighted to help. No pressure. No sales patter.