My 2-years old CO detector (small, wall-mounted device with battery, no other power source) started beeping every morning for at least few minutes, sending sharp chirps once every 10 sec. It starts around 6am.
I don't see any visible fire or cooking in my apartment or outside. I've read that it might mean end of battery/detector life, temperature change, or poltergeist. Are these the most common reasons?
I will replace battery to check for some of it.
UPDATE: Changed battery, chirping went away
If your CO detector were actually detecting CO, it would not chirp. It would sound a continuous, and very, VERY loud alarm you would definitely recognize.
The chirping is a universal (as far as I know) method for indicating that it's time to change the battery. This is true for CO and smoke detectors.
It's normal for gas and smoke detector batteries to indicate impending failure during the coolest part of the day. The chemical reaction that produces the electrical current is reduced by low temperatures. It's a common occurrence in cold climates, especially in the case of vacation homes that are kept at lower temperatures when not in use.
Chances are the battery should've been replaced long ago. Do it now and see what happens.
A low battery is the most common cause of seemingly-random chirps in smoke and CO detectors. Detector end of life is probably the second most common cause.
How old is the CO detector? Their lifetime is somewhere in the range of 5-10 years, depending on the make/model (source source source), so if it that old or older, it's best to replace the whole thing.
Volunteer firefighter here who has seen many a CO detector malfunction..
I think the answers here are spot on but I'll just add on:
Some CO detectors, when set off, sounds like a BEEP-BEEP-BEEP then a pause and it continues with the series of beeps, etc. They're loud but not as loud as a commercial fire alarm in say a school or public building is. Most detectors go off at the early stages of CO being a problem (10-15ppm). As firefighters we have to put on our SCBA (masks) at 70ppm (this varies by department)
Definitely check the back of your detector and look for the date of manufacture. If it was manufactured 4-5 years ago it may be time to get a new one. CO detectors don't last forever so replace it if it's old.
And of course, make sure you replace the batteries, or at least check them, every 6 months or so. The cold causing he low power alert to go off is plausible but if it continues you may have to replace it (see above!) Some detectors plug right into the wall but have battery backups. Make sure you still check those as well!
Of course, if it ever does go off, do not hesitate to call 911. The fire department has the tools to check your home if it is hazardous to your health. A CO alarm is definitely no laughing matter and it should be taken seriously.
If the battery were failing, it would not chirp at the same time every day, it would chirp and continue chirping all day. Having said that, if it's easy, and it should be, replace the battery. If it still chirps - at the same time every day- you can rule out battery. this is the first step.
The next step is to look outside at the neighbor's car.
