Carbon monoxide (CO) in homes is almost always produced by burning fuels like gas, wood, oil, charcoal, or gasoline when combustion is incomplete.

What produces carbon monoxide in homes?

The main things in a house that can produce carbon monoxide are:

  • Gas appliances: gas stoves, ovens, gas clothes dryers, gas water heaters, and gas boilers or furnaces when they’re faulty or poorly vented.
  • Heating systems: fuel-burning furnaces, boilers, and space heaters that use natural gas, propane, oil, kerosene, or coal.
  • Fireplaces and wood/coal stoves: wood-burning or gas fireplaces and wood stoves, especially with blocked or closed chimneys/flues.
  • Portable fuel heaters: kerosene or other unvented fuel heaters used indoors.
  • Generators and engines: gasoline or diesel generators, power tools, lawn equipment, or running vehicles in attached garages—even with the door open.
  • Charcoal grills and camp stoves: any charcoal or fuel-burning grill used indoors, in garages, or in enclosed patios.
  • Tobacco smoke: indoor smoking also adds carbon monoxide to indoor air.

In short, any device that burns a carbon-based fuel and isn’t vented or working properly can fill a home with carbon monoxide.

Quick Scoop: key points and safety tips

  • CO is a colorless, odorless “silent killer” gas from incomplete burning of fuels like wood, petrol, coal, natural gas, and kerosene.
  • Homes with fuel‑burning appliances or attached garages have higher risk.
  • Common sources: furnaces/boilers, water heaters, gas stoves/ovens, fireplaces/wood stoves, generators, vehicles in garages, grills, and some space heaters.

Simple prevention checklist

  1. Install certified carbon monoxide alarms on every level and near sleeping areas.
  1. Have furnaces, boilers, gas water heaters, and fireplaces serviced at least yearly by a qualified technician.
  1. Never run generators, grills, or vehicles inside garages, basements, or enclosed porches (even with doors or windows open).
  1. Keep vents, flues, and chimneys clear of debris, nests, or snow so exhaust can escape.
  1. Avoid using unvented fuel heaters indoors unless local guidance clearly allows and ventilation is adequate.

If anyone in the home has sudden headache, dizziness, nausea, or confusion and you suspect carbon monoxide, get everyone outside immediately and call emergency services.

Mini SEO-style extras

  • Focus phrase “what produces carbon monoxide in homes”: CO comes from fuel‑burning appliances (furnaces, water heaters, stoves, fireplaces), engines, and grills when they don’t vent properly or are used indoors.
  • A recent update from a state health department in February 2026 again stresses that any burning material in a home—especially with attached garages—is a potential CO source.

TL;DR: In homes, carbon monoxide is produced by anything that burns fuel—gas appliances, heaters, fireplaces, engines, and grills—when combustion is incomplete or exhaust cannot vent outside.

Information gathered from public forums or data available on the internet and portrayed here.