Smoke Alarm Insanity

I am going crazy here. Last night about 12:00AM our smoke alarm went off on the 2nd floor. Took a tour of the house (stubbed my toe twice in the dark) No fire, no smoke, nothing anywhere. Took a magazine and waved air across the detector and it stopped. Went back to bed. An hour later same thing happened. I decided to unplug the detector from the wire harness. All our smoke alarms are hard wired, and are about 16 years old. I figured maybe this particular detector was done for and just needed replacement.

So today I bought a new smoke alarm from Home Depot. Killed the power at the breaker panel, made all the new wiring connections, and returned power to the circuit. Instantly the new smoke alarm goes off. I took a battery powered detector from the basement and brought it upstairs with a fresh battery to see if perhaps there was something going on that my nose did not detect. Nothing. Not even a chirp.

Anybody have any suggestions or ideas? I have unplugged the new smoke alarm, and returned power to the other detectors in the house, and am keeping the battery operated one upstairs for the time being…

I am stumped here…

The only thing that rings a bell with me is some info I got from a client once…

They had some semi hidden plumbing leaks in a new home and said a smoke alarm started going off. Fire dept came out and could find nothing except some water leaking.

I suggest checking the attic area over that detector for moisture problems.

Take all the smokes that are hardwired and take 'em down. Take a shopvac and blow them all out. While they are down, replace the batteries in them. That tends to fix the problem. I’ve had to do this to a few houses.


Hey John…

Shouldn’t you be over at Austin’s Saloon watching the 80’s cover band Sixteen Candles? :stuck_out_tongue:


I believe a smoke that is 16 years old may have out lived its life i believe they have an expiration date i will try to find it.

I found this will look for more.
Funny how we end up on bets over the weirdest things. Well with your bet with your friend, you loose. The guiding advice about smoke detector replacement seems to come from the National Fire Protection Agency (NFPA), they recommend replacing smoke detectors every 10 years (max). It seems that there is concern about electronics operating 24/7 for more than 10 years. So officially you loose, but from this knowledge, you gain the possibility of fixing a problem that might exist. Are your home’s smoke detectors over 10 years in age? Be a hero, change them. :wink:

I am aware of the 10 year replacement guideline. Thanks. Doesn’t explain why the brand new one is going off. I will try cleaning them all, and look for moisture in attic above. Thanks guys!

Anyone else have any ideas?

John, I’m thinking your house is on fire. Dial 911; Get off the computer and the Nachi site and go outside. :wink:

Just curious, are they ionization or photoelectric?

All the alarms need to be compatible. Mixing brands doe not work. Even within the same brand some will not work with others.

Change all of them. The failure rate past 10 yrs. is great.

Bumped into a similar situation once, but in a HIGH Humidity situation.

Hope this helps. I learned allot.

When I get a service call for interconnected smoke detectors intermittently going off for no clear reason, I have one course of action. They all get replaced. Just saves callbacks on a system that probably has some age on it anyhow. It can be hard to find a matching smoke detector for a system that’s already installed anyhow, and they must match for proper operation. You can monkey around with a shot in the dark for weeks or you can just replace them all. I choose the latter.

I have to agree with Marc. Typically when I ran into intermittent smoke detector problems, the detectors were out of warranty, and exceeded/close the NFPA age recommendations. The only time I didn’t recommend total replacement, it would be when I found a smoke detector in an ‘unconditioned’ space. Then I would talk about getting a ‘heat’ detector instead.

This is a reflection, not advice. My advice is to get a qualified electrician involved. Smoke detectors save lives, and locally we had a few lost because of things like batteries pulled out, being disconnected, etc.


I just added on 1800 SF with 5 interconnected smoke alarms. All brand new. Not connected to any other alarm in the old part of the house. Mine went off about 3 times in the middle of the night for no apparent reason (always at night it seems). Scared the poop out of me. They finally quit the false alarms. Haven’t had a problem in months. I say give it some time. Perhaps call the manufacturer…I was planning to do that but never got around to it.

Thank you gentlemen for the info and suggestions. I went out and dropped $100 on new detectors and installed them all. No problems now (knock on wood). I will sleep better at night now with no alarms going off, and some peace of mind!


I think it must have been a compatability issue as the new detector was not the same brand. Now they all match, and I am in compliance with the new CO detector rule!

Are sure they work ? Just asking