It's a good idea to have at least one CO alarm installed on every level of your home. To help prevent unwanted alarms try to keep at least a 15-20 foot distance between the CO alarm and the heating appliance. Do not install your alarm in the garage or in areas of high humidity or where it will be exposed to strong chemical solvents or cleaners. If you have a plug in alarm, do not install in an outlet controlled by a light switch or dimmer or in an area where it can be easily knocked off the wall. Make sure it is not blocked by furniture, curtains or other obstructions.
Carbon monoxide is roughly the same weight as air and distributes evenly throughout a room.
If a smoke alarm senses smoke, it alarms immediately. CO alarm technology is little more complex. The CO alarm measures the amount of carbon monoxide and the time of exposure. Carbon monoxide alarms measure levels of carbon monoxide over time and are designed to sound an alarm before an average, healthy adult would experience symptoms. It may be a higher amount of CO over a short period of time or a lower amount for an extended time frame.