Carbon monoxide in a home usually comes from anything that burns fuel and is poorly vented, broken, or used indoors when it shouldn’t be. Common sources include furnaces, water heaters, gas stoves/ovens, fireplaces, wood stoves, kerosene heaters, generators, and vehicles in an attached garage.

Main sources

  • Gas appliances: stoves, ovens, dryers, water heaters, furnaces, and boilers can produce carbon monoxide if they malfunction or are not vented properly.
  • Fireplaces and wood-burning stoves: blocked chimneys or poor ventilation can let carbon monoxide back into the house.
  • Space heaters and kerosene heaters: fuel-burning heaters can release carbon monoxide, especially with poor airflow.
  • Vehicles and generators: running a car in an attached garage or using a generator indoors or too close to windows can create dangerous buildup.
  • Charcoal grills and other fuel-burning tools: these should never be used indoors because they can produce dangerous carbon monoxide.

Important note

Carbon monoxide is colorless and odorless , so you cannot detect it by smell or sight. If you have fuel-burning appliances at home, a working carbon monoxide alarm is important.

If you suspect exposure

  • Get everyone outside into fresh air immediately.
  • Call emergency services if anyone has headache, dizziness, nausea, weakness, confusion, or fainting.
  • Do not re-enter until the source is found and the home is considered safe.

If you want, I can also give you a quick checklist of the most common CO risks room by room.