[b1webber]

Going off 8 hours after going to bed - alarm going off while still sleeping around 7 am in morning - what would alarm be sensitive to when house is quiet and everyone sleeping?

 

[kbsparky]

How old is the unit?

Anything from dust build-up to a rogue spider can make `em do this.

You may need to clean it up (VACUUM it), or replace it if it's more than 7 years old ...

 

[k_buz]

Are they combination smoke/CO detectors?

Are they "chirping" or is it actually going off?