How to Fit a Smoke Alarm

When it comes to the safety of your home, a smoke alarm is an essential piece of equipment.

When it comes to the safety of your home, a smoke alarm is an essential piece of equipment. The UK Fire Service estimate that they are called to over 600,000 fires each year, 50,000 of which are house fires. That means that there are 140 house fires on average every day in the UK. They also estimate that house fires are the cause of 500 deaths and 11,000 injuries each year. What’s more, you’re twice as likely to die in a house fire if you don’t have working smoke alarms fitted in your property. This guide will give you information on different fire alarm types, where you should place them, how to maintain them and how to fit a battery powered smoke alarm in your home.

Types of Smoke Alarm and Where to Install Them

There are several types of smoke alarm, each with their own unique way of detecting a potential fire. These alarms are suited to placement in different areas of your house; the more properly fitted alarms, the more protection you have. It’s important to note that you don’t need to fit a fire alarm in your bathroom as steam from hot water can cause the alarm to go off.


Ionisation smoke alarms tend to be the cheapest of the bunch. They work by sensing particles of smoke and are very sensitive. We would recommend that you don’t place an ionisation smoke alarm in your kitchen as it will be triggered by even the smallest particle of smoke caused by burnt toast for example.

Where to place them:

  • Landings, preferably slightly away from the kitchen

Optical or Photoelectric

Optical smoke alarms are more expensive than ionisation alarms, however they’re more sensitive to smouldering flames that would come from a burning sofa, burning wire or mattresses. These fire alarms ‘see’ smoke, detecting larger particles and are slightly less sensitive to small particles that would come from burnt toast, however we still recommend that you don’t place one in your kitchen to avoid annoying, false alarms.

Where to place them:

  • Living rooms
  • Hallways (can be near kitchen)
  • Bedrooms

Heat Detectors

Heat alarms are ideal for use in places where smoke, steam or fumes are frequently present in the air. A heat detector will, as the name suggests, detect temperature increases but aren’t sensitive to smoke. These alarms tend to cover a small area so if you’re fitting one in a large kitchen, then it’s best to fit two.

Where to place them:

  • Kitchens
  • Garages

Combined Alarms

There tends to be two types of combined smoke alarm: heat and optical alarms and smoke and carbon monoxide alarms. Heat and optical combination alarms use multiple sensors for efficient and effective fire detection, reducing the number of false alarms and – more importantly – making for speedier detection of fires.

Where to place them:

  • Landings
  • Bedrooms
  • Living rooms
  • Hallways

You can buy radio-interlinked smoke alarms that go off in unison when one of them detects smoke or heat, meaning that you’ll be alerted to potential danger no matter where you are in the house.

While smoke alarms can either be battery-powered or mains-powered, most mains-powered alarms will be combination in case of power shortages in the mains. Mains-powered smoke alarms must be fitted in any new builds or after any major refurbishment, and must be fitted by a qualified electrician. If you are simply replacing a broken or old fire alarm in your current property, you can still install a battery powered alarm.

NB: Ensure that the smoke alarms you choose to fit in your property are certified to British and European standards.

Fitting a Battery Powered Smoke Alarm

What you will need:

  • Measuring tape
  • Pencil
  • Drill
  • Hollow wall plugs/plasterboard anchors or a stud finder
  • Fire alarm and fixings (screws and sometimes wall plugs)


  1. Find a ceiling joist if possible. If you can’t find a joist, you’ll need wall plugs.
  2. Using your measuring tape, find a spot on the joist that is at least 30cm from any wall, door or light fitting.
  3. Using your pencil, mark fixing points for drilling using the base plate of smoke alarm. If you have found a joist in a suitable spot, use a stud finder to find an area that is safe to drill before marking fixing points.
  4. Drill holes using your fixing point markings. If you have NOT found a joist, drill into the plasterboard and put wall plugs/anchors in the holes to reinforce them before doing anything else.
  5. Screw the baseplate of the smoke alarm to the ceiling. However, be careful not to do this too tightly as you risk damaging the wall plugs that will reinforce your placement holes.
  6. Fit the alarm battery and then the main body of your smoke detector to the baseplate, following the manufacturer’s guidelines.
  7. Test your new alarm.

Maintaining and Testing

Ensuring that your smoke alarm in good working condition and testing it regularly could save lives. We recommend:

  • Choosing a day of the week as your smoke alarm test day and keep a note of it somewhere visible so you don’t forget.
  • Changing your smoke alarm battery annually, even if it still works perfectly, unless you’ve purchased a ten-year alarm.
  • Replacing your smoke alarm every ten years.
  • Cleaning your smoke alarm a few times a year
    • Use the soft brush attachment on your vacuum to carefully vacuum the alarm, clearing the sensors of any dust.