the smoke detectors in my house started beeping tody. 1 or 2 beeps evey couple of hours. they do not have batteries as they are wired directly into the house. what would cause this and what do i do about it??? it sounds like the old detectors that i had that had batteries in them. just a beep to let you know the batteries were going dead.
i took one apart to see if i could disconnect it and it didn't look like you could disable it without cutting the wire. obvously i wouldnt do that but was still wondering what causes the beep and what to do about it??? when i press the test button, it goes off like it should

Are all of them beeping? Are you SURE they don't have batteries?

My parents house has them and they have a battery backup. When that battery starts going dead they beep.

I don't think anybody makes hardwired smoke alarms without battery backup.

What brand and model are they?

the brand is FIREX smoke alarm. i do not see batteries if they are there. it also says "warning this will not operate during loss of power"

They have to have batteries incase the power goes out. There should be a small cover on the bottom or the side that is against the ceiling. Some require the use of a small screwdriver others just have a battery cover similar to your tv remote control. They take a 9 volt battery. If you are replacing one, you should replace all since they are tied together via the hard wire. Have fun and be safe change your batteries.

Also the hard wired type go bad at times and they will beep to let you know one is faulty. Pain in the rear to find out witch one is bad.
More than likely its is batteries.
Went through a freinds house because of faulty one. Drove us crazy for days to find out one was installed in a closet that was bad. Bad dectctor! Bad boy!

How old are they? Its recommended to replace all smoke detectors every 10 years, if older than 10 years might as well replace them all.

Are any of the LED lights blinking? If its one blink every 30 seconds it means you have a faulty detector and should replace it.

If yours don't have a battery backup, I bet they are old. Do yourself a favor and get new ones. The wiring should be easy provided you have some electrical experience. Better to drop a hundred bucks to re-outfit the whole house than wait for the chance to see a 10 year old detector fail to do its job.

It's like headlights, if one burns out you might as well just replace both of em.

I've had them start beeping when their "useful life" is up.

Lot of times you can get some dust balls in there. You can usually take a vacuum cleaner to them.

Are these carbon monoxide detectors also?

Older models never had battery backup and were direct wired, I would replace one of them to see if this is a problem before changing all out...or you might have a power surge/electrical problem?