Short answer
If a carbon monoxide alarm sounds, get everyone, including pets, outside into fresh air and call 911 or your gas utility's emergency line. Don't go back in until responders say it's safe. Then have a licensed technician inspect the furnace, water heater and venting before using them.
Right now
Carbon monoxide is odorless, and symptoms such as headache, dizziness and nausea feel like the flu.
- Leave the house and leave the door open behind you.
- Call 911, or Spire (Missouri) or Kansas Gas Service (Kansas) from outside.
- Get medical help for anyone with symptoms.
Common sources
In Kansas City homes, the most common sources are a cracked furnace heat exchanger, a blocked or disconnected flue, a water heater backdrafting into a shared chimney, a car running in an attached garage, and generators or grills used too close to the house.
Before using the furnace again
A technician should inspect the heat exchanger, test combustion, check the flue and draft, and confirm the water heater vents properly.
When to call a technician
- Any time the alarm sounds, after the home has been cleared.
- The alarm chirps with low battery or is past its replacement date.
What the technician does: see furnace tune-up & safety check.
Common questions
Where should CO alarms be installed?
On every level and outside sleeping areas, following the manufacturer's instructions.
How long do CO alarms last?
Usually 5 to 10 years. Check the date on the back.
Editorial note: this guide is general information for Kansas City-area homeowners, not a diagnosis. Conditions vary by home, so a licensed HVAC technician should confirm the cause before any repair.