We were awakened last night when something beeped three times. Got up, looked around, didn’t see anything obvious, so we went back to sleep. Again, three beeps about ten minutes later. This time, we got up, turned on all the lights and checked things. Nothing. So here is what it wasn’t:
Smoke alarms: all are hard-wired. If the backup batteries get low, they will persistently chirp one time until you either remove the battery or replace it.
CO detector: is in the bedroom and is very loud. Wasn’t that.
Refrigerator: will start beeping if the door is left open for a long time. Door was closed and internal temps were correct.
Home security alarm: no error messages on the screen, which will happen if anything goes wrong, from a dead detector battery to other faults.
Discharged phone battery: nope, doesn’t make that noise when going dead.
Temporary power glitch: the toaster oven will beep three times when power comes on after a momentary loss. But the settings also reset, which didn’t happen. Also, all the clocks are showing correct time.
Noise from outside the house: nope. It’s been so hot that all the windows were closed so the AC could keep things cool.
I’m completely flummoxed here. Nothing has beeped since that second time. Any ideas?