What Is a Carbon Monoxide Risk With Furnaces and What Symptoms to Watch For?

Q: Can a furnace cause carbon monoxide, and what symptoms should I watch for?

A: Yes—fuel-burning furnaces (such as natural gas, propane, or oil systems) can create carbon monoxide (CO) if there is a combustion or venting problem. CO is dangerous because you cannot see or smell it, and early symptoms can feel like the flu. If a CO alarm sounds or anyone has symptoms like headache, dizziness, nausea, confusion, chest pain, or trouble breathing, get everyone to fresh air and call 911 right away.

Common Symptoms to Watch For

• Headache
• Dizziness
• Weakness or unusual fatigue
• Nausea or vomiting
• Confusion
• Shortness of breath
• Chest pain
• Sleepiness or feeling “off”

Carbon monoxide poisoning symptoms are often described as flu-like (without a fever), which is one reason CO exposure can be missed. If multiple people in the home feel sick at the same time, especially when the furnace is running, treat it seriously. :contentReference[oaicite:0]{index=0}

Safety First

• If a CO alarm sounds, do not ignore it.
• Move everyone outside or to fresh air immediately.
• Call 911 and follow emergency instructions.
• Do not keep troubleshooting while people remain inside.
• Do not restart the furnace until the home is declared safe and the system is inspected.

If someone is confused, collapses, has severe breathing trouble, or is hard to wake, treat it as an emergency and call 911 immediately. CDC guidance lists headache, dizziness, weakness, upset stomach/vomiting, chest pain, and confusion among the most common CO poisoning symptoms. :contentReference[oaicite:1]{index=1}

Quick Checks You Can Do

These steps are only for after everyone is safe and only if there is no active CO alarm sounding:

1. Check CO alarms: Confirm your alarms are installed, powered, and not expired.
2. Replace batteries if needed: Follow the alarm manufacturer’s instructions.
3. Check the thermostat setting: Make sure the heating call is normal and not causing short cycling.
4. Check the filter: A severely clogged filter can stress a heating system (though it is not a direct CO cause by itself).
5. Look for obvious airflow blockage: Keep supply/return vents open and clear.

Do not open combustion compartments, adjust burners, disconnect venting, or attempt furnace repairs yourself.

What Creates Carbon Monoxide Risk With a Furnace

Combustion problems

If fuel is not burning correctly, the furnace can produce dangerous gases, including carbon monoxide.

Venting or flue issues

If exhaust gases cannot vent properly to the outdoors, CO can spill back into the home.

Cracked heat exchanger concerns

In some cases, damage or failure in furnace components can create unsafe conditions and requires professional diagnosis.

Poor maintenance and wear over time

Dirty components, aging parts, or neglected tune-ups can increase safety risk and reduce reliable furnace operation.

Important Clarification for Florida Homes

Many Florida homes use heat pumps or electric heat instead of fuel-burning furnaces. A standard electric furnace / electric resistance heat system does not create CO from combustion because it does not burn fuel. CO risk is associated with fuel-burning equipment and other combustion sources, such as attached garages with running vehicles or generators used too close to the home.

CO Alarm Basics for Homeowners

• Install CO alarms on every level of the home.
• Place alarms near sleeping areas so they can wake you up.
• Follow manufacturer instructions for placement and replacement dates.
• Test alarms regularly.

NFPA recommends CO alarms outside each sleeping area and on every level of the home, and EPA notes each floor should have a detector, with a single detector placed near sleeping areas if only one is used. :contentReference[oaicite:2]{index=2}

What Beacon Usually Checks

When there is a furnace safety concern, our friendly technicians in yellow focus on safe system evaluation first.

• Overall furnace operation and shutdown behavior
• Airflow and filter condition
• Visible venting and exhaust concerns
• Safety controls and system response
• Signs the system should remain off until repair or replacement

If there is any suspected CO event, emergency response and home safety come first. System service happens after the immediate hazard is addressed.

When to Call Beacon

If your furnace is acting unsafe, short cycling, producing unusual smells/noises, or you want a heating system safety check, Beacon can help inspect the system and explain your options clearly.

Request Service
(352) 726-7530
www.BeaconSaves.com

Prevent This Next Time

• Install and maintain CO alarms on every level and near sleeping areas
• Replace furnace filters on schedule
• Schedule regular heating system maintenance
• Do not ignore unusual furnace behavior or repeated shutdowns
• Never run generators in or near enclosed spaces

📍 Contact Beacon Services & Appliances
📞 (352) 726-7530
🌐 www.BeaconSaves.com.