Carbon monoxide detectors

Chicago, IL – Many homeowners easily see the value of installing a burglar alarm or a smoke detector. A burglar could steal thousands of dollars in personal property, and a fire could destroy the entire structure. However, there is another hazard that doesn’t always get proper attention: A colorless and odorless toxic gas called carbon monoxide. Carbon monoxide is a by-product of burning carbon-based fuels, such as firewood, coal, natural gas or gasoline. Proper ventilation does help keep the concentration level of carbon monoxide below toxic levels, but it’s not always possible to ventilate every area in a home.

Carbon monoxide poisoning is often associated with excessive car exhaust in a closed garage, but there are other potential production sites for carbon monoxide, including furnaces, wood-burning fireplaces, gas-powered water heaters and kitchen stoves. Anywhere carbon-based fuel is converted to heat is a possible source for carbon monoxide, and it can reach toxic levels within a few minutes in some situations.

The solution to this potential household hazard is the installation of at least one carbon monoxide detector on every floor of the home, especially in areas where there is combustion on a regular basis. Carbon monoxide detectors can save lives, and many models are also designed to detect smoke and fire, which makes them even more essential for household safety.

What is carbon monoxide?

Carbon monoxide is a toxic gas produced when carbon is not completely burned during combustion, such as a gas fire in a furnace, wood in a stove, charcoal in a grill or gasoline in an engine. Single carbon atoms bond with single oxygen atoms to form an invisible gas that is much more dangerous to humans than the more common gas carbon dioxide. Carbon dioxide can also be toxic in higher concentrations, but most buildings are ventilated well enough to prevent a dangerous carbon dioxide build-up.

When carbon monoxide molecules enter the body through inhalation, they pass through the lungs and enter the bloodstream where they form a bond with red blood cells. These affected blood cells no longer bond with normal oxygen molecules, and eventually, the body shuts down from lack of oxygenated blood. Medical intervention can reverse the damage caused by carbon monoxide poisoning, but quite often the initial symptoms resemble other illnesses, and immediate treatment is not sought.

How do carbon monoxide detectors work?

Carbon monoxide molecules can be chemically or electronically sniffed through several different technologies. Some carbon monoxide detectors contain a gel that reacts with carbon monoxide and changes color. This color change is detected by sensors, which trigger an audible alarm. The carbon monoxide generally has to reach a certain level of concentration before detection, and the gel does have a limited lifespan.

Other carbon monoxide detectors use a metallic semiconductor coated with silica. When the silica absorbs enough carbon monoxide molecules from the air, the electrical resistance changes and an alarm sounds.

A third option commonly used in home carbon monoxide detectors also involves changes in electrical resistance. Small electrodes inside a chemical solution continuously monitor the quality of the outside air. Carbon monoxide molecules eventually lower the electrical resistance of the solution, which trips the alarm. Many carbon monoxide detectors can also provide nearly real-time concentration levels on a display screen.

Carbon monoxide detector features

Power source

Most carbon monoxide detectors for home use are battery-powered, much like smoke detectors. Standard alkaline batteries are the norm, but some models also work with rechargeable lithium-based batteries. A hardwired carbon monoxide detector is far less common than a hardwired smoke alarm or intruder alarm system.


Some basic carbon monoxide detectors do not have visual displays but are designed to go off when a certain carbon monoxide concentration has been reached. Higher-end models have LCD screens that display the current carbon monoxide level, plus any previous data that could show a trend, such as a rise in carbon monoxide near a gas-burning appliance. A detector with a real-time display allows users to take steps to reduce carbon monoxide levels before the situation becomes toxic.


Because many carbon monoxide detectors use sensitive chemical agents, they do lose their effectiveness over time. While some manufacturers claim a lifespan of 10 years or more, it is safer to assign an average lifespan between 5-7 years. Carbon monoxide detectors do have a testing option, and homeowners can arrange for a professional to simulate higher carbon monoxide concentrations for the test.

Best carbon monoxide detectors

Google Nest Protect Smoke and Carbon Monoxide Detector: available at Amazon 

This next-generation smoke and carbon monoxide detector analyzes the surrounding air hundreds of times a day and can detect both slow-building carbon monoxide concentrations and fast-building flame or smoke. The manufacturer claims a 10-year lifespan and smart technology provides interconnectivity with other NEST products and smartphones.

First Alert CO615 Dual-Power Plug-In Carbon Monoxide Detector: available at Amazon.

The First Alert can be plugged into a wall socket for continuous monitoring, but also contains a battery backup. Its affordable retail price makes it easy for homeowners to meet the suggested “one carbon monoxide detector per floor” minimum without breaking the budget. An 85-decibel alarm and a digital display round out its features.

Sensorcon Industrial carbon monoxide Carbon Monoxide Monitor: available at Amazon.

Although primarily used for commercial inspections, this lightweight and portable professional-grade monitor can be used to investigate possible carbon monoxide concentrations in private homes as well. Multiple alarm methods (vibration, audio, visual) and an ultra-sensitive sensor will definitely alert users of any carbon monoxide hazards.

Kidde AC Plug-In Carbon Monoxide and Explosive Gas Detector Alarm: available at Amazon.

If carbon monoxide and explosive gas build-ups are both potential issues in a location, this dual sensor from Kidde is one to consider. Users can plug it directly into any household AC outlet or mount it on a wall near a socket. It does contain a battery backup if power is disrupted. Digital display shows peak carbon monoxide levels throughout the day.

Kidde Carbon Monoxide Alarm: available at Amazon and Home Depot.

This battery-powered carbon monoxide detector is Kidde’s entry-level model, which means users get the benefit of Kidde technology without a major upfront investment. It’s ideal for installation in campers, RVs, tents and other temporary shelters with heating or cooking sources. The 85-decibel alarm is definitely loud enough. The unit chirps like a smoke alarm when battery power is low.

X-Sense Combination Smoke and Carbon Monoxide Detector Alarm: available at Amazon.

Another dual smoke and carbon monoxide on our shortlist, this wall-mountable unit features a lithium battery with a 10-year lifespan. Both smoke and carbon monoxide detectors work independently and each will issue a unique alarm pattern when activated. It can be mounted on the ceiling for smoke detection, but we recommend a lower location for carbon monoxide monitoring.

Safe-T-Alert by MTI Industries Dual LP/CO Alarm: available at Amazon.

For households with liquid or natural gas-powered appliances, this dual gas leak/carbon monoxide detector offers peace of mind. It is flush-mounted, which means a less noticeable profile than the battery-powered wall-mounted competitors. A 12-volt power source eliminates the need to replace dead alkaline batteries frequently.

Koabbit Combination Carbon Monoxide Detector and Natural Gas Detector: available at Amazon.

This affordably priced natural gas and carbon monoxide detector can be hardwired to a range of AC sources or powered with a rechargeable battery. The digital display is easy to read, and updates occur frequently enough to spot trends before they reach toxic levels.

UEi Test Instruments Carbon Monoxide Detector: available at Amazon.

Marketed primarily to professional contractors, this high-end carbon monoxide detector and alarm is extremely sensitive and can analyze up to 999 ppm of carbon monoxide. The unit is always set to continuous analysis, which means it will definitely alert users to potential carbon monoxide build-up in construction sites, crawlspaces and other less-accessible areas.