Nothing feels cozier than a warm house on a cold winter night. But be careful: the Centers for Disease Control report that carbon monoxide exposures are at their highest rates from chilly November through February, when people close their homes up tight and sometimes rely on defective or improperly vented heat sources to keep warm. About 500 people die each year in the United States from carbon monoxide poisoning, dubbed the “silent killer” because carbon monoxide is a deadly colorless, odorless gas. Victims often don’t realize they’re sick until it’s too late.
Deadly amounts of carbon monoxide can also build up quickly inside RVs and campers.
Symptoms of carbon monoxide poisoning at lower concentrations include headache, fatigue, nausea, and dizziness—symptoms that might be mistaken for the flu, and that should improve if you leave the house. At higher and potentially deadly concentrations, symptoms include confusion, vomiting, loss of muscle coordination, and loss of consciousness.
Choices in carbon monoxide detectors
A carbon monoxide alarm is not a substitute for a working smoke detector with fresh batteries. Fire and health officials recommend using carbon monoxide alarms in addition to smoke detectors. Stand-alone carbon monoxide alarms come with their own power sources (either hard-wired or plugged in, with a battery backup). Look for an alarm with the Underwriters Laboratories seal and an audible alarm. Check the label to see how many years the alarm will work before it must be replaced. Combined carbon monoxide alarms and smoke detectors in a single unit are also available.
Some carbon monoxide detectors come with digital displays that show the carbon monoxide concentration in parts per million. That can be useful as most carbon monoxide alarms are made to trigger at 70 parts per million, but concentrations below that—even as low as 30 parts per million—can be dangerous for pregnant women, people with heart problems, and children.
A rising concentration on the display could be an early warning of a mechanical problem that needs to be inspected and repaired immediately.
Where to install, when to test
The Consumer Product Safety Commission recommends placing a carbon monoxide alarm in the hallway outside each sleeping area of the house—either plugging them into an electrical outlet or placing them high on the wall (carbon monoxide will rise). The commission recommends not placing them near heating vents or in kitchens. If the house has multiple floors, consider having multiple alarms.
Test the alarms at least monthly, weekly is better, following the manufacturer’s instructions.
And don’t run a car, operate an electrical generator, or use a charcoal or gas grill in a garage, even if the garage doors are open.