re: #68 b_sharp

But don’t leave that as a permanent solution. You might check to see if it’s also a CO detector.

AFAIK, CO detectors aren’t required in new construction like smokes are; typically speaking, if there isn’t an installed alarm system, most CO detectors are plug-ins with battery backups. From what SS is saying, it’s likely a smoke that’s either dirty or is just going bad; not really much you can do in the middle of the night, except to cut power to the offending sensor and look at it during the day.