So we're spending a few days at the river. I was pleased that I was able to get the house up from 40'-->68' within 5 or so hours with outside temps of 17' when I got there (that's pretty darn cold for VA). This morning, awoke at 06:30 to the sound of the smoke detector in my 15 month old's room. I ran into the room, and was confused as to what exactly was going off. Didn't smell smoke, so initially assumed it was the CO detector. It was registering 0. Weird thing was, there's another smoke detector probably 6 feet from the alarming one in the hallway. His door was open and that one wasn't going off. I hadn't loaded the insert since about 6p the night before; it was cold enough that the blower had shut off. Anyway, I was still freaked out, and nobody was going back to sleep at that point. Later on, I put the battery back in and a few minutes later it started alarming again. The battery is a bit weak (didn't have a replacement 9v handy), but usually they just chirp when weak. Has anyone had an alarm malfunction like that? The manufacture date on the alarm is 2008, FWIW...