r/FireAlarm

Hi. I have several of these alarms in my house. They are no more than a couple months old and are estimated to last 10 years. Twice now, they have started going off. Both instances happened at night time. There was obviously no fire or smoke, and all of our windows are closed. Thinking it may be the CO alarm but we have nothing turned on/combusting that could produce CO (furnace, fireplace, etc.) Any help is appreciated of why this might be!