I just bought one CO detector, plug-in w/ battery backup and digital display (the deluxe model). Thought I'd use it in the basement where the furnace is, and where we already know we have had a backdraft problem with the insert (which shares the chimney which vents the furnace). I was wondering if I should get a couple more, for each room with a wood stove? Kind of a belt-and-suspenders approach. Appreciate any thoughts.