We drove up to our high-country home on Thursday, and just got back down to the valley this afternoon. There was still some snow on the ground.
The first night, we were waken up by the maddening periodic chirping of one of the smoke alarms. The backup battery was running low in the alarm at the very top of the ceiling, a 15-ft height from the loft. Not having an extension ladder, we closed the door of our downstair bedroom, and tried to sleep. Finally figured out that running the space heater fan continuously helped drowning out the torturious chirp. For a while, we thought we had to drive down to the valley at 11PM !
Came the next morning, the chirping stopped. It occured to me then, that the voltage of the 9V battery was right on the verge of the warning threshold. The voltage increased with warmer temperatures during the day, and the warning chirp stopped.
Sure enough, the chirping resumed the next night at 10PM. The pattern repeated while we were there. The white noise from the heater fan worked great!
I then remembered that last time we were up here, about 2 months ago, we were awaken by the same warning chirp of the smoke alarm right in the bedroom. That one, I could reach with a shorter ladder, which I had to fetch in the middle of the cold dark night from the detached garage, with my eyes barely opened and mind still hazy from sleepiness.
I had failed to see that the batteries in the other alarms were in imminent failure, and to make the precaution to bring up the extension ladder to change them. I am getting senile!!!