Carbon Monoxide is a legitimate and somewhat elusive hazard. According to the Consumer Products Safety Commission, Carbon Monoxide is associated with approximately 500 (non-fire related) deaths in the U.S. each year. Furthermore, due to their elevated metabolic rate, small children are more susceptible to its damaging effects.
Why it is dangerous: Carbon Monoxide (CO) is odorless, colorless, invisible, and mixes evenly with air. Elevated levels cause flu-like symptoms and drowsiness. It is particularly dangerous if a buildup occurs while residents are sleeping, as it may prevent them from waking, and it is frequently fatal.
Where it comes from: Carbon Monoxide is a natural product of the combustion process and, as such, it can be emitted from gas-fired appliances or equipment. The most frequent culprits within the home are fireplaces, water heaters, furnaces, ovens, and stoves. Should the burner element or the exhaust flue of any these become cracked, CO may re-circulate within the living space. Ironically, both newer and older homes are susceptible. Older homes tend to have older appliances and equipment that are more likely to malfunction. However, older homes are draftier, and as a result, CO will take much longer to build up to a dangerous concentration. Newer homes are so well-insulated and tightly sealed for energy efficiency that even a small leak may build up to a dangerous level.
How to mitigate it: Preventive maintenance on all gas-fired equipment and appliances will significantly reduce the likelihood of CO release. Furnaces and water heaters, in particular, can be readily checked by a qualified HVAC technician. CO Monitors are now available to continuously monitor the level within the home. Both AC and battery-powered units are available at most of the home centers and will sound an alarm should an elevated level of CO be detected. In most homes, one detector adjacent to the sleeping areas will suffice. Larger homes may require additional units.
What else to consider: While the number of CO-related deaths is significant, it is a mere fraction of the fire-related ones. So, while you consider adding a CO monitor, make sure your smoke detectors (with fresh batteries) are less than 10 years old, located on each level of the home, in each bedroom and in the adjacent hallway. By the way, combination CO Monitors and Smoke Detectors are now available to enable you to address both issues with a single unit.