MY SMOKE DETECTORS GO OFF IN THE MIDDLE OF THE NIGHT(OF COURSE!) ABOUT TREEE TIMES A YEAR. I HAVE A TOTAL OF SEVEN THAT ARE WIRED TO GO OFF WHEN ONE IS TRIGGERED. I HAVE CHANGED THE BATTERIES IN ALL OF THEM AND BLEW THEM OUT. EXCEPT FOR ONE OCCASION WHEN IT WAS TWO NIGHTS IN A ROW, IT IS ALWAYS ONE NIGHT.THEY START UP AND THEN STOP, THEN START AGAIN. THE AMOUNT OF TIMES AND LENGTHS OF TIME VARIES. ANY IDEAS ON WHY THIS IS HAPPENING?? OBVIOUSLY, IT IS VERY A L A R M I N G IN THE MIDDLE OF SLEEP!!

Could it have something to do with the Twilight Zone?!
Seriously Donald, I'm wondering if a power surge could trigger them to go off? Just a thought.

I've read about poor air quality triggering smoke alarms. If you live someplace that is subject to smog, that might be the problem.

Donald,

You don't state when, during the year, your smoke detectors go off. It is possible that they are doing what they are designed to do, but, without knowing more, one can only guess. For example: if there are open windows, and someone used the outdoor barbecue, either at your house, or at the neighbor's, the residual smoke drifting into the house through open windows might trigger the alarm. Or, the self-cleaning oven could set it off, especially if grease and debris is allowed to accumulate. More importantly, if, the first time you turn on your furnace or boiler during the autumn season, the alarm goes off, then you have a problem with your heating system or chimney, not with the smoke detectors. Some smoke detectors, the kind that do not use ionization in their detection system, can be set off by the flicker of light passing through the blades of a rotating ceiling fan, so be sure to ascertain whether yours use a photo cell in the detection mechanism. An electrician can determine this for you.

It goes without saying that all smoke detectors should be kept clean, by periodically vacuum cleaning them, so that dust accumulation doesn't affect performance.

I'm new to the boards, but I read your post and thought I might be able to help you. We had the same problem, and it was really annoying. After replacing the batteries, we started thinking about the smoke detectors themselves. We determined which one was setting them all off and replaced it, and we haven't had any problems since then. Check your manual to see if your detectors have a feature that shows you which one of the networked units initiates the alarm. It might be a flashing light or some other such thing. Many smoke detectors are designed to last ten years or so, but they can go bad before that. Good luck!

I had the same problem with only one in a series of 4. I could determine which one was the culprit as the green light blinks. These detectors are wired in with battery back up. I blew out the detector and reset it.
Yes, very alarming in the middle of the night when there seems to be no problem.
See if yours has that feature of blinking or not. Also, I ended up running a ceiling fan as it occurred in the summer, although we have central air.
Good luck.

Looking into the reasons for false alarms with smoke detectors... national fire assoc points out several locations.. NOT recommended for smoke detectors... kitchen, attic, utility area, garages, unfinished basements etc. Often we install them in those places... these areas lend themself to false alarms and in a short time often disable / contaminate your alarms. Steam, hair spray, cooking, air ducts, dust and temp. above 100 degree affect ionization alarms performance...negatively! It wasn't until 1999 that the NFPA code stated "put smoke alarms in every sleeping area/room"...
Invisible particles often set off Ionization smoke alarms and photo-cell alarms would NOT be activated by a fan or a shadow in a room as suggested... the photo cell is located inside the alarms.. the blinking light simply indicates the alarms has power.. and another notion that pushing a button to test the alarm in fact only checks the power source (batter or hard wired power) not the actual workings of the alarm. hope this info helps?

I too have had smoke detectors going off unexpectedly!! My solution was to check each one and clean them!!--I found dust and cobwebs in all of them--once I wiped or vaccuumed them, they have been fine--you have to literally take each one down, turn it over and inspect it as well as the connections on the ceilings!
Hope this helps you!

It may be nothing more than a nocturnal spider walking over the sensor.

I found a combo alarm with 3 in 1 features:
1.rate of rise (15 degrees in 60 sec) notification 2. fixed temp 135 degree and 3. photo cell with a disaposal dust filter . No insect can get into the chamber. No guessong what acivated the alarm. A micro processor (chip) control- resets the alarm every 25 hrs for drift compensation.. the test button give a blinking readout on service needed...including the ten year battery a 6-7 dollar item. No guess work... trouble shooting, cleaning, trying find out wat' sup with the unit ..I came across that 3 in one unit about 4 years ago.

I have three of the four in a series withing 8 feet of one another (code stated one in each bedroom near door and one in hallway) I wired the additional one through the floor of one of the bedrooms into the lower level bedroom.
When we have had false alarms in the middle of the night, it becomes very frightening because my children hear three of these - really loud and have no idea what is going on. I found that the one culprit alarm is in a west side bedroom which gets a lot of sunlight. The problem so far has been on hot sunny days. We run the ceiling fan in that room constantly and don't seem to have issues. ALso, yes spiders love them! I hit the detectors with the vacuum attachment or the duster. Room temp and humidity are two things that the manuals said to watch for. Mine are wired in with battery back up and they have a green light that shows power. Another light will blink as it tests but if the detectors go off, the cluprit or detected alarm's other sensor light will continue to blink. Makes it easier to trouble shoot.