Testing a smoke alarm: why you cannot smell smoke in your sleep and how to check it every month

General information, not legal advice. The exact smoke alarm obligation differs by region; for your home, the rules of your region and the advice of your fire and rescue zone apply.

Testing a smoke alarm is a small job that is easy to put off, whether you live with a young family, live alone, or rent out or rent a home. Now that winter time has started and candles, heating and fireplaces are back in use, it is a good moment. Below you can read why you do not smell smoke in your sleep, what the rules are, where an alarm belongs and how to check it every month.

Why you do not smell smoke in your sleep

Brandweerzone Centrum, a fire and rescue zone in East Flanders, puts it bluntly: you smell nothing when you are asleep and the smell of burning does not wake you. According to the zone, most fatal victims die at night, suffocated by smoke, which is much more dangerous than the fire itself. Two out of three fatal fire victims die between 9 pm and 6 am.

A small sleep laboratory study from the United States points the same way. Six young adults aged 20 to 25 were given smells through the nose during their sleep. In the lightest sleep they still responded to 92 percent of the trials. In deeper sleep peppermint no longer woke them, and a sharp test odour never did in the deepest sleep. A tone worked in at least 75 percent of the trials. It is a very small study with young people and test odours instead of real smoke.

In Belgium, Oscare, the aftercare and research centre for people with burns and scars, counted at least 55 deaths in house fires in 2025, compared with 75 in 2024. Of those 55, 25 died in a fire at night. That count dates from 29 December 2025, so from just before the end of the year.

What the Flemish and Brussels smoke alarm rules require

In Flanders, every home must have smoke alarms on every floor, and since 1 January 2020 this also applies to homes where the owner lives. According to the Flemish brochure on housing quality, the alarm must meet the NBN EN 14604 standard. In rented homes, the landlord buys and installs the smoke alarms. If the device has replaceable batteries, the tenant replaces them in time. In Brussels, smoke alarms have been mandatory in all homes since 1 January 2025, including for owners who live there themselves.

The fire service recommends more than that minimum: according to Brandweerzone Centrum, an average family needs 6 to 8 smoke alarms to be warned in time. That is advice, not an obligation.

Where a smoke alarm does and does not belong

Smoke rises, so you mount the alarm on the ceiling, preferably in the middle and, according to Vlaanderen.be, at least 30 centimetres from the wall. Put one in every room on the shortest escape route from the bedroom to the outside. In the kitchen, mount it away from steam and the cooking area, in the garage close to the inside door. Not in the bathroom, where the risk of false alarms is too high, and not near an open window, a ventilation opening or above a radiator.

Choose an optical smoke alarm with a CE marking; ionisation smoke alarms are banned in Belgium. A model with a fixed 10-year battery is recommended, because a smoke alarm lasts at most 10 years. Interconnected alarms all go off as soon as the first one sounds. After installing, check that you can hear the alarm in every room, even with the doors closed.

Testing a smoke alarm and maintaining it: the monthly check

Test the smoke alarm at least once a month. Brandweerzone Centrum suggests making it a habit, for example every first Thursday of the month. Here is how:

• Press the test button and listen whether the alarm goes off.
• Remove dust now and then with a cloth or vacuum cleaner, never with water, because too much dust makes the alarm work less well.
• Replace replaceable batteries in time: a 9V battery lasts about a year, AA batteries usually 2 to 3 years.
• Replace the whole smoke alarm after 10 years at the latest.

If you heat with a stove or fireplace, also read how to place a CO detector in the heating season. Autumn evenings also bring candles back to the table, and what they do to the air at home is explained in the article on candles and indoor air.

Sources

• Brandweerzone Centrum, a fire and rescue zone in East Flanders. Rookmelders (smoke alarms, in Dutch). Accessed in October 2026.
• Flemish government, Vlaanderen.be. Rookmelders (smoke alarms, in Dutch). Accessed in October 2026.
• Flemish government, Wonen in Vlaanderen. Wonen doe je niet op goed geluk. Check de woningkwaliteitsnormen (housing quality standards, in Dutch). Brochure, accessed in October 2026.
• Carskadon MA, Herz RS. Minimal olfactory perception during sleep: why odor alarms will not work for humans. Sleep, 2004 (sleep laboratory study with 6 participants).
• BRUZZ. Minder doden bij woningbranden in 2025 door verplichte rookmelders in Brussel. 29 December 2025 (in Dutch, figures from Oscare).