Carbon Monoxide and Furnace Safety: When to Leave
When to Leave Immediately
- A carbon-monoxide alarm sounds.
- Someone in the home develops possible CO symptoms, especially if they improve outside.
- You smell gas, see soot, or notice an unusual burner flame. CO itself has no smell, but other furnace problems may be noticeable.
Once outside, follow the instructions of emergency responders, your gas utility, or a qualified HVAC professional before re-entering or operating the furnace.
What Carbon Monoxide Has to Do with a Furnace
Fuel-burning furnaces can produce CO. It can become dangerous when equipment is improperly vented, damaged, or not operating correctly. A water puddle is not a reliable sign of a CO problem, and a water leak should never be used to rule one out.
If Your Furnace Is Leaking Water
Water around a furnace is more commonly related to a condensate drain, pump, humidifier, or air-conditioning drain issue. If there is no safety concern, use our separate furnace leaking water guide for safe homeowner-level checks. If there is any possibility of combustion-gas exposure, stop and seek professional help instead.
Lowering Carbon-Monoxide Risk
- Install CO alarms near sleeping areas and follow the manufacturer’s replacement and testing instructions.
- Have fuel-burning heating equipment and related appliances serviced annually by a qualified technician.
- Keep furnace vents and exhaust paths unobstructed; do not use a gas oven to heat the home.
- Never run generators or fuel-burning equipment indoors or in an attached garage.
Official Source
CDC: Carbon Monoxide Poisoning Basics