I have a 2 story house with a basement and an attic. I have a 9V smoke detector on each level, which is 4 total. On the second floor, which is where my bedroom is, I have a CO detector and smoke detector all-in-one.
This morning around 4am, one of the smoke detectors went off for about 15 seconds and then shut off. It wasn’t chirping like the battery was dead, it was the full on alarm. I am not even sure which one it was. I jumped out of bed and ran around sniffing for smoke but didn’t find any so I went back to bed.
I do replace the batteries when the clocks change twice a year. I blow the dust out of them at that time also. One of the smoke detectors is new but I do not know the age of the rest of them.
What would cause the smoke alarm to go off and then shut itself off?
I have worked in the fire alarm industry for 32 years. My job is commercial fire alarm, which uses detectors that are connected to a central control panel rather than the single station “household” type detectors. The detection methods are the same.
Home smoke detectors are very inexpensive and easy to change. When there is the slightest doubt that they are functioning correctly, discard them and install new detectors. That being said, make sure you are installing the correct detectors. Ionization detectors detect non-visible products of combustion, and do not detect black, sooty smoke very well. Photo electric detectors do a much better job of detecting smoke. The best detector to use is a combination Ion/Photo, which will detect either type of fire.
The guys at the Barre City Fire Department in Vermont have a series of videos that demonstrate the difference here
The aquarium test video is the best demonstration of the issue with choosing the wrong type of household smoke detector.
All sorts of things like dust, bugs, spiders, and bits of floating bits of animal hair or spider webs can set off a smoke detector. If the smoke detectors have been up there for a while, or your house is fairly dusty, or you have pets that shed, etc. you may want to buy a can of compressed air and spray it into the smoke detectors to clean them out.
a bedroom or the floor bedrooms are on should have both CO and smoke detectors. also good to have both where you have a furnace/boiler for heating.
you can get single unit CO alarms, both ceiling and wall plug in (to AC receptacle).
you can get combination ceiling CO and smoke (either ion or photo) though i have never seen all three.
some alarms will have a feature where a LED might keep flashing after wards on an alarm that has triggered to let you know, this is common on networked alarms. some CO/smoke combo alarms will distinguish which alarm has sounded.
CO alarms might have a lifetime of maybe 7 years. ionization detectors about 10 years.
an insect or dust can trigger a photo alarm that could be a one time event.