Carbon monoxide detector

What It Means

A carbon monoxide detector, usually called a CO alarm, watches the air for carbon monoxide and sounds a loud alarm when the level gets dangerous. CPSC and NFPA advise one on each level of the home, plus one in a central spot just outside each separate sleeping area.

How It Sounds at Home

• "The CO alarm is chirping again, can you check it?"
• "We put a carbon monoxide detector in the hall by the kids' rooms."
• "Is that the smoke alarm or the CO one?"

The Breakdown

Set it up

1. Put a CO alarm in a central spot outside each separate sleeping area.
2. Add one on every level of the home.
3. Skip the attic and the basement unless someone sleeps there.
4. Choose interconnected alarms if you can, so when one sounds they all do. CPSC and NFPA both call this the best setup.
5. Test each alarm once a month and change replaceable batteries every year, as CPSC recommends.

When it sounds

1. Don't go looking for where the gas is coming from.
2. Get everyone outside into fresh air right away.
3. Call 911 or the fire department from outside.

Try it today. Walk the house and count sleeping areas and levels. That count is how many alarms the placement advice calls for, before any extras.

Good to Know

CDC lists the most common symptoms of carbon monoxide poisoning as headache, dizziness, weakness, upset stomach, vomiting, chest pain and confusion, and notes they are often described as flu-like. The same CDC page warns that people who are asleep or drunk can die from CO before they have any symptoms, and that breathing in a lot of it can make a person pass out. If anyone has symptoms, get them into fresh air and call 911. The heating check-up that goes with a CO alarm is covered on the furnace maintenanceFurnace maintenanceThe routine care a furnace needs: a monthly filter check, a yearly professional cleaning and inspection before heating season, and a working carbon monoxide alarm. See more page.

Related Terms and Categories

• Smoke detector testing

  Pressing a smoke alarm's test button once a month to make sure it sounds, and replacing the alarm 10 years after the date it was made.

• Furnace maintenance

  The routine care a furnace needs: a monthly filter check, a yearly professional cleaning and inspection before heating season, and a working carbon monoxide alarm.

• Fire escape plan

  A household's agreed way out in a fire: two exits from every room, an outside meeting place, and a drill practiced at least twice a year.

• Family emergency plan

  A written plan a household agrees on ahead of time for how it will reach each other, where it will meet and what it will do in a disaster or emergency.

• Generator maintenance

  The routine care that keeps a home generator ready for an outage: oil changes, filter and spark plug checks, test runs and safe storage.

Home maintenance and repairs