Carbon monoxide kills approximately 400 Americans every year and sends 100,000 to the emergency room. It has no color, no smell, and no taste. By the time you feel its effects — headache, dizziness, confusion — you may already be too impaired to act. This guide covers everything you need to know to protect your family.
Where CO Comes From
Carbon monoxide is produced by the incomplete combustion of carbon-based fuels. In a home, the main sources are: gas furnaces and boilers (especially with cracked heat exchangers), gas water heaters, gas stoves and ovens, fireplaces and wood stoves, attached garages (car exhaust), portable generators, and gas dryers. Any fuel-burning appliance can produce CO if it malfunctions or is improperly vented.
- A cracked furnace heat exchanger is the most dangerous CO source — it's invisible and requires professional inspection
- Never run a generator, grill, or camp stove inside or in an attached garage
- CO risk increases dramatically in winter when homes are sealed and heating systems run constantly
Recognizing CO Poisoning
CO poisoning symptoms mimic the flu — but without fever. Early symptoms include headache, dizziness, weakness, upset stomach, vomiting, chest pain, and confusion. The critical difference: symptoms improve when you leave the home and worsen when you return. If multiple family members (or pets) are sick at the same time, CO poisoning is a serious possibility.
- Pets are often affected before humans — a dog or cat that's suddenly lethargic is a warning sign
- CO poisoning during sleep is especially dangerous because you don't wake up
Detector Placement
CO detectors should be installed on every level of your home, including the basement. Place them within 10 feet of each bedroom door so the alarm wakes sleeping occupants. Install one near (but not directly above) any fuel-burning appliance. CO is slightly lighter than air, so mid-wall placement (5 feet high) is ideal — though ceiling placement also works. Do not place detectors in dead air spaces (corners) or directly next to cooking appliances.
- Combination smoke/CO detectors are convenient but test both functions separately
- CO detectors have a lifespan of 5–7 years — check the manufacture date on the back
- Interconnected detectors (all alarm when one triggers) provide the best protection
What to Do When the Alarm Sounds
If your CO alarm sounds: immediately move everyone (including pets) outside to fresh air. Do not stop to gather belongings. Call 911 from outside — do not re-enter the home. Wait for emergency responders to clear the building and identify the source. Do not re-enter until the source has been identified and repaired by a qualified technician.
- Never silence a CO alarm and go back to sleep — even low-level CO exposure causes long-term neurological damage
- If you suspect CO poisoning, go to an emergency room even if symptoms seem mild
Prevention: Annual Inspection Is the Key
The most effective CO prevention is an annual inspection of all fuel-burning appliances by a licensed HVAC technician. They check heat exchangers for cracks, verify proper venting, and test combustion efficiency. This inspection costs $75–$150 and is the single most important thing you can do to prevent CO exposure. Also: never block or cover vents, keep the area around appliances clear, and have your chimney inspected annually if you use a fireplace.
- Schedule furnace inspection in September — before heating season and before technicians are fully booked
- A yellow or orange furnace flame (instead of blue) indicates incomplete combustion — call a technician
CO Detectors Are Not Optional
As of 2024, 38 states require CO detectors in residential buildings. Even if your state doesn't mandate them, install them anyway. A combination smoke/CO detector costs $25–$50 and takes 5 minutes to install. It's the cheapest life-safety investment you can make.
Schedule a Furnace Safety Inspection
Our licensed HVAC technicians inspect heat exchangers, check venting, and verify safe combustion — the most important CO prevention step you can take.