Carbon monoxide detector

A carbon monoxide detector or CO detector is a device that detects the presence of the carbon monoxide (CO) gas to prevent carbon monoxide poisoning. In the late 1990s, Underwriters Laboratories changed the definition of a single station CO detector with a sound device to carbon monoxide (CO) alarm. This applies to all CO safety alarms that meet UL 2034 standard;^[1] however for passive indicators and system devices that meet UL 2075, UL refers to these as carbon monoxide detectors. Most CO detectors use a sensor with a defined, limited lifespan, and will not work indefinitely.

CO is a colorless, tasteless, and odorless gas produced by incomplete combustion of carbon-containing materials. It is often referred to as the "silent killer" because it is virtually undetectable by humans. In a study by Underwriters Laboratories, "Sixty percent of Americans could not identify any potential signs of a CO leak in the home".^[2] Elevated levels of CO can be dangerous to humans depending on the amount present and length of exposure. Smaller concentrations can be harmful over longer periods while increasing concentrations require diminishing exposure times to be harmful.^[3]

Those living in all-electric homes don’t need CO detectors unless there is an attached garage with a non-electric car, or if a backup generator is used too close to your living quarters during a power outage.^[4]

CO detectors are designed to measure CO levels over time and sound an alarm before dangerous levels of CO accumulate in an environment, giving people adequate warning to safely ventilate the area or evacuate. Some system-connected detectors also alert a monitoring service that can dispatch emergency services if necessary.

While CO detectors do not serve as smoke detectors and vice versa, combined smoke/CO detectors are also sold.^[5] In the home, some common sources of CO include open flames, space heaters, water heaters, blocked chimneys or running a car or grill inside a garage.^[6]