Carbon Monoxide is a deadly gas which is colorless and odorless. In most fatal home fires, it’s carbon monoxide which kills victims long before they succumb to smoke inhalation or are burned by the fire.
Early symptoms of carbon monoxide poisoning are similar to the flu, making it difficult to detect by symptoms alone. These symptoms can include a dull headache, weakness, dizziness, nausea, shortness of breath, confusion, blurred vision and chest pain. Since most people are more familiar with the flu than with CO2 poisoning, they assume their symptoms are flu-related, prolonging their exposure to the gas making them sick; this can be a fatal error.
Unlike smoke, which is fatal if the concentration in the air is high enough, carbon monoxide usually builds up in the system over time. One can get carbon monoxide poisoning from either a low concentration of carbon monoxide over a long period of time or a high concentration over a short period of time. Therefore, carbon monoxide detectors need to determine the average level of carbon monoxide in the environment over time, determining if it is high enough to cause problems.
Smoke detectors don't detect carbon monoxide. If you have a smokeless fire going or a contained fire, it’s possible for carbon monoxide levels to reach fatal levels without a smoke detector going off. This could also occur with vehicle exhaust, a leaky furnace or an improperly vented hot water heater for example.
Ideally, you should have both carbon monoxide detectors and smoke detectors in your home. A minimum of one per floor is recommended, with additional detectors installed in bedrooms. Although this make for a lot of detectors, it provides the best protection for your family. Having a detector go off in the basement, when everyone is asleep on the second floor of the house doesn't help anyone.
Carbon monoxide detectors can run off of your house current, battery or a combination of the two. In the cases where a detector uses both, the battery serves as a power backup for the AC house current. That way, you’re always guaranteed a working detector, even in a power outage nor worry about the battery dying at the wrong time.
The best carbon monoxide detectors are now using Lithium-Ion batteries for prolonged battery life and they’ll also have a test button-like a smoke detector. Some models are now made so several units can be interconnected with one another; if one alarm goes off, it will alert and activate the others in your home. Check out our top picks for best carbon monoxide detectors in 2022 .