Why does my smoke alarm keep going off?

For the third time in a little over two years, the complex I live in will be replacing my smoke alarm tomorrow. It went off for no reason tonight for the third time with three different alarms.

(I know it’s a false alarm - I’ve inspected my entire apartment, the hallway, the garage, and the dumpster. I’m staying up for a couple hours, but then I’ll only have an hour left to sleep; I might as well go to work. [/Pit rant])

I know that dust can affect them. I hit it with the feather duster every time I clean. Is there any other reason I could be getting so many false alarms out of every smoke alarm I’ve had in this place?

Don’t know about yours, but my smoke alarms beep at intervals when the battery is low.

It is powered from a power feed in the ceiling. It was a full-fledged alarm attack. (The objective observer would likely have been amused watching groggy me trying to unhook the thing.)

Things that can go beep in the night.
Smoke Alarm (low battery)
Carbon Monoxide detector (same reason)
Mobile phone (and again)
Land line answerphone (message)
Computer switched on (son getting in late but must check something)
Microwave (son getting in late but must eat something)

I’m not arguing with your diagnosis TYM but my wife had me looking for a beep a few weeks ago in the middle of the night, and I realised then how many things beep these days (and nights) :slight_smile:
It turned out to be the Carbon Monoxide detector.

There are usually two causes for a hard-wired smoke detector to go into alarm for no apparent reason.

The first is that the detector is dirty. Hitting the case with a feather duster won’t stop the dust buildup inside the sensor itself. Vacuum the detector out, that should clear any dust or insects from the sensing chamber inside the detector.

If that doesn’t work, its definately the second problem. The detector has lost its will to live. The usual lifespan of a smoke detector is about 10 years. As the detector gets older, it becomes more and more sensitive. When it would take a goodly amount of smoke to set it off when first installed, slight dust in the air or steam from a shower will set it off 8 or 10 years down the line. You did say that the complex has replaced them before, so its possible that they are replacing it with an older detector (they bought extras when the system was installed and use those as replacements).

The alarm company that services the system can dial down the sensitivity of most smoke detectors. Perhaps thats something to suggest to the powers-that-be.

I haven’t called them yet. I’ll try vacuuming it out when I get home. Kind of dumb not to have thought of that.

Each time it’s been replaced, it’s been with an identical alarm. I wouldn’t be surprised if they have boxes and boxes of them in maintenance. Maybe I should just buy my own new one.


I had an ionising-radiation smoke alarm that kept going off. The cure was to throw it away and replace it with a new one. I think KCB615 hit the nail on the head - it has lost the will to live. Replace it with a different model if you’re getting the same results with different units of the same type, for they appear to be shit, and a useless smoke detector is worse than useless.