Smoke alarms: where to fit them and how to test them

2 min read · 8 steps · Updated 3 October 2026

Short answer

Fit a smoke alarm on the ceiling of every bedroom, outside each sleeping area and on every level of the home. Press the test button once a month. Change replaceable batteries at least once a year, and replace the whole alarm ten years after the date of manufacture printed on it.

The smoke of a fire at night can overcome people in their sleep, long before the flames reach them. A working smoke alarm wakes you while there is still time to get out. The advice below follows the US Fire Administration. Many countries, including Germany, make alarms compulsory in bedrooms and hallways.

Step by step

  1. Put them in the right places

    One inside every bedroom, one outside each sleeping area, such as the hallway, and at least one on every level, including the basement.

  2. Mount them high

    Smoke rises, so fit alarms on the ceiling, in the middle of the room if possible, or high on the wall. Keep them away from corners, lamps and air vents.

  3. Test once a month

    Press and hold the test button until the alarm sounds. If it stays silent, change the battery, and if that does not help, replace the alarm.

  4. Look after the battery

    Alarms with a replaceable 9-volt battery need a new one at least once a year. Many newer alarms have a sealed battery that lasts ten years and is not changed.

  5. React to the chirp

    A short beep every minute or so means the battery is nearly empty, or on a sealed alarm that the alarm has reached the end of its life. Do not take the battery out and forget it. Replace it the same day.

  6. Replace the alarm after ten years

    The sensor wears out. The date of manufacture is printed on the back or the side. Ten years after that date, replace the whole alarm, even if the test button still works.

  7. Handle false alarms from cooking

    Open a window, wave a towel under the alarm to clear the air, or press the hush button. Never remove the battery to stop it.

  8. Choose well when you buy

    Interconnected alarms all sound together when one detects smoke, which matters in a larger home. For people who are deaf or hard of hearing, there are alarms with a flashing light and a vibrating pad for under the pillow.

Good to know

If you rent, check who is responsible. In Germany the landlord must install the alarms, and in many federal states the tenant has to keep them working, unless a service company does the yearly check.

Vacuum the alarm gently once or twice a year. Dust in the chamber is a common cause of false alarms.

A smoke alarm does not detect carbon monoxide. Homes with a gas boiler, a wood stove or an open fire need a separate carbon monoxide alarm.

Agree on an escape route and a meeting point with everyone at home. The number for the fire service across the EU is 112: emergency numbers in Germany.

In short: An alarm in every bedroom, outside sleeping areas and on every level, on the ceiling. Test monthly, new battery yearly unless sealed, new alarm after ten years.

Sources
  • US Fire Administration: Smoke alarms

Rules and prices change. Check the official source before you act.