One short chirp. Then quiet. Then another one, right when you’re about to fall back asleep. If your smoke detector does this in the middle of the night, it’s almost always telling you the battery is getting weak.
Why it happens at night
Batteries put out less power when they’re cold, and most houses are coldest between about 2 and 6 a.m. A battery that was getting by in the afternoon dips below what the alarm needs once the heat drops overnight, so the low-battery chirp starts. It can even stop once the house warms back up, which is why it’s so easy to forget about by breakfast.
What to do
- Swap the battery. If one alarm is low, the others probably aren’t far behind, so do them all at once.
- Still chirping? Check the date on the back. Smoke alarms are meant to be replaced every 10 years, and many chirp when they reach the end of their life.
- Press the test button. New York’s Department of State suggests testing at least twice a year.
The New York part
Since April 1, 2019, any new or replacement smoke alarm sold in New York has to be hard-wired or have a sealed battery that lasts at least 10 years. You don’t have to tear out working alarms that met code when they went in. But the next time you replace one, you’ll end up with the sealed kind, and that’s the end of 3 a.m. battery swaps.
If you’re getting a house ready to sell, this is an easy one to handle early. Old or missing smoke detectors are exactly the kind of small thing an inspector writes down.
Sources: Kidde and the New York Department of State.
