There are several carbon monoxide (CO) detectors in your apartment or house. Always remember that carbon monoxide detectors need to be able to sniff the air if they are going to protect you from carbon monoxide poisoning. If they can’t smell the air, they are useless. Do you have furniture up against a CO detector? Are the air intake holes in your carbon monoxide detector blocked by something? If so, you have effectively disabled that carbon monoxide detector. Check your carbon monoxide detectors. Do you have stuff blocking their ability to sniff the air?

Should carbon monoxide detectors be mounted near the floor or the ceiling? It doesn’t seem to matter. I went to landlord association meeting once where safety expects debated this question, but without coming to a conclusion. Carbon monoxide is heavier than air, so it would seem logical to assume that carbon monoxide concentration should be greater at the floor than at the ceiling. However, it isn’t that simple. Generally, when carbon monoxide is present in a room, it is coming from a kitchen stove or a gas furnace. All stoves and furnaces produce warm air, and warm air rises to the ceiling, taking carbon monoxide with it. Also, carbon monoxide is only slightly heavier than air, so the natural movement of air in a room
can make carbon monoxide circulate throughout the room. As a result, it doesn’t seem to matter whether a carbon monoxide detector is mounted near the floor or the ceiling. What does matter is whether the carbon monoxide detector has an unobstructed ability to smell the air, which is all-important. I mount carbon monoxide detectors near the floor, where it is easier for tenants to read and test their carbon monoxide detectors. Also, if a false alarm goes off, I don’t want a tenant to have to get on a ladder to silent it.