Tonight at about 2 AM my wife and I were awakened by our fire alarm system going off in full alarm mode. I quickly jumped up and pressed the button to reset the system and they all stopped. We checked the house and everything was fine. We had the same thing happen about a year ago, again in the middle of the night.

Our house is almost 3 years old. We have 8 fire detectors and one carbon monoxide detector. The carbon monoxide detector is in the basement near the furnace. The are all hard wired together and have battery backups.

Is this normal? Should I be concerned? Do I need it checked by a pro? What may be the cause? Are we haunted?

  • Do you have any heat/smoke detectors in your attic?
    – mikes
    Jun 11, 2015 at 10:02
  • Nope, nothing in the attic. Jun 11, 2015 at 12:02
  • 1
    How old is the smoke detector? They do have a definite lifespan; may be time to replace.
    – keshlam
    Jun 11, 2015 at 15:39
  • Same age as the house, about 3 years. Jun 11, 2015 at 18:20
  • @keshlam good point. most guides seem to suggest 10 years, so it's probably not that.
    – bib
    Jun 14, 2015 at 21:06

4 Answers 4


You may have batteries getting old. You need a battery tester (not expensive). Even new batteries can be faulty, and supply low voltage to an appliance. This will cause a fire alarm to false-trigger, sometimes.

  • I was advised by one manufacturer that the internal battery tester on the interconnected (wired) units tests the battery under load. Batteries can look fine with no load, but the voltage plunges when you put a load on them. You need a battery tester that tests the batteries with a load appropriate to the battery type and size. A simple tester that just checks the no-load voltage won't tell you whether the smoke alarm will see it as bad.
    – fixer1234
    Oct 1, 2017 at 18:06

According to Kidde’s website, 2am alarms are commonly associated with failing batteries. Small drops in room temperature create more resistance on the battery, which temporarily fails, then mimics an alarm state. Find the alarm that’s setting off the system (it usually is the 1st to go off, followed very shortly thereafter by others on the wired system), and replace the battery. If that doesn’t fix the problem, or you can’t ID the specific unit, replace batteries in all units. And if that doesn’t work you may be looking at having to replace a unit

  • 1
    Welcome to Home Improvement. This is a old question, but you've made a great point! It would be very helpful if you would edit in the actual link to the website so others can read in more detail if they want. You've also done well by not simply linking (as some do), but also including the pertinent info, since links can die. Please take the tour and read the help center (especially on answering) to pick up more tips. Come on back and participate some more!
    – FreeMan
    Jul 17, 2020 at 13:40

A random beep does not a crisis make. Electronic sensors twitch sometimes. If there were a real smoke or CO2 condition, the alarm would almost certainly go off again after reset, probably immediately.

However, you should test each of the alarms immediately, and again regularly to ensure they are working. And, if it happens again in the near future, call in a pro.

  • And testing means holding something burning under the smoke detector, not just using the button on the device.
    – Grant
    Jun 12, 2015 at 1:15

Town could also be switching grids. Happened to me 3 years in a row just after batteries were changed.

Not the answer you're looking for? Browse other questions tagged or ask your own question.