Carbon Monoxide detectors are necessary just like smoke detectors. Carbon Monoxide (CO) is an odorless, colorless, and toxic gas. Most people who suffer from exposure to Carbon Monoxide poisoning or at worst death were not even aware of their exposure to this toxic gas. The purpose of installing a CO Detector is to reduce the chance of any exposure that would result in hospitalization or in worst cases death. It is now code in many areas to have a Carbon Monoxide Detector in your home, even if you do not have a fuel-burning appliance, if you have attached garage. While terms such as CO Alarm and CO Detector (or Monitor) may seem to be the same product they are actually quite different. CO Alarms are designed to alert the occupants to a level of CO that is life threatening. A CO Detector/Monitor are designed to alert the occupants of low levels before the situation becomes life threating and they still provide an alarm at the higher life threating levels. Much like a smoke detector is an early warning of fire as opposed to a fire alarm where the fire already exists. CO Alarms come in many sizes, shapes, and styles. It is best to have the low-level type of detector/monitor that will alert any occupants of the presence of CO at levels as low as 30 ppm. Standard CO alarms activate at 70ppm after 2-4 hours. This rating is for healthy male adults, however most homes are not occupied by healthy male adults alone. Many have elderly adults and or small children, in which case these types of CO alarms may not provide adequate protection. Manufacturers of standard CO Alarms have started to add disclaimers to their products; however, the consumer must be diligent in reading the fine print. The following is one such disclaimer: "Pregnant women, infants, children, senior citizens, persons with heart or respiratory problems and smokers may experience symptoms at lower levels of exposure than noted. Individuals with medical problems may consider using warning devices which provide audible and visual signals for carbon monoxide concentrations under 30 ppm." Whether you buy an alarm or a detector/monitor, it is a good idea to write the date on the device when you install it so you know to replace it in five years (or when recommended by the manufacturer).