Question:
I just finished talking with a co worker who is recovering from a carbon monoxide scare. she had been sick for the past while and found out recently when they checked out her basement and found CO at 700 ppm. She had been sleeping with the door and window closed and it was making her perpetually ill. Here's the scary part, she said she had these 1/2 smoke 1/2 CO alarms in her house. even though the basement was at 700 ppm. (which according to the specs on my kidde alarm should make it sound in 4 minutes) none of her alarms sounded. ( I don't know what brand she had) This made me question my own alarm. I tested it, and it seems to function correctly. however, I'm not sure where it should be placed. Reading online some say that the detectors should be placed on the ceiling, because the CO is mixed in with the warm furnace air that rises. However, the person who checked out my co workers house said that the CO generally falls, and so the detectors should be lower to the ground. what do you all think? This is the alarm I have http://www.kidde.com/utcfs/ws-384/Assets/9CO5%20sheet.pdf

Answer: Would also be important to know how old the detector was. I'm not sure what I'd do in this position. With levels that high, one would think the detector would go off in either location. Personally, since I don't spend much time on the ceiling, I have mine about 4 ft of the floor. I have one in the basement, about 15 ft from the furnace/water heater, another one in the master bedroom. I think it's a very good idea to have more than one, as like anything they aren't 100%. Your friend should consider contacting the Consumer Product Safety Commission, they may be interested in checking it out.