Carbon monoxide (CO) doesn’t hiss.
It doesn’t smell.
It doesn’t give second chances.
And that’s exactly why carbon monoxide safety comes before comfort, efficiency, or repair costs.
80,000 BTU 96% AFUE Upflow/Horizontal Single Stage Goodman Gas Furnace - GR9S960803BN
This guide is not about fear—it’s about awareness, prevention, and knowing what to do when something feels off. Savvy’s goal is simple: help you recognize risks early and respond correctly, without panic or guesswork.
🧠 What Carbon Monoxide Is—and Why Furnaces Are Involved
Carbon monoxide is a byproduct of incomplete combustion. Any appliance that burns fuel can produce it:
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Gas furnaces
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Boilers
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Water heaters
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Fireplaces
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Gas stoves
Your furnace is designed to burn fuel cleanly and vent exhaust safely outside. When that process breaks down, CO can build up indoors.
Savvy truth:
Carbon monoxide problems are rarely sudden explosions. They’re usually quiet system failures.
🚨 The Symptoms of Carbon Monoxide Exposure (Know Them Cold)
CO poisoning often looks like the flu—but without a fever.
Early Symptoms:
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Headache
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Fatigue
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Dizziness
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Nausea
Advanced Symptoms:
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Confusion
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Chest pain
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Shortness of breath
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Loss of consciousness
Children, elderly adults, and pets are affected faster and more severely.
Savvy rule:
If multiple people feel “off” at the same time—don’t troubleshoot. Get outside.
🔔 Section 1: Carbon Monoxide Detectors — Your First Line of Defense
CO detectors are not optional accessories. They are life-saving devices.
Every Home Should Have:
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CO detectors on every level of the home
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A detector near sleeping areas
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Fresh batteries (or hardwired units tested regularly)
Monthly Savvy Check:
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Press the test button
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Replace batteries at least once a year
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Replace detectors per manufacturer lifespan (usually 5–10 years)
🔗 External reference:
👉 https://www.cdc.gov/carbon-monoxide/about/index.html
🚪 Section 2: What to Do Immediately If a CO Alarm Goes Off
This matters more than anything else in this article.
If the Alarm Sounds:
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Get everyone outside immediately
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Do not open windows “just to check”
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Call emergency services or your gas utility
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Do not re-enter until cleared by professionals
What Not to Do:
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Don’t reset the alarm and wait
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Don’t try to diagnose the furnace
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Don’t assume it’s a false alarm
Savvy mantra:
CO alarms are never an inconvenience—they’re a warning.
🔗 External reference:
👉 https://www.aga.org/natural-gas/safety/
🔥 Section 3: Furnace-Related Causes of Carbon Monoxide Problems
Carbon monoxide doesn’t appear randomly. It has causes.
Common Furnace-Related Triggers:
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Cracked or failing heat exchanger
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Blocked or disconnected venting
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Improper combustion air supply
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Dirty burners
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Improper installation or modification
Why High-Efficiency Furnaces Still Matter Here:
Even 90%+ AFUE furnaces can produce CO if:
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Intake/exhaust pipes are blocked
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Condensate drains back up
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Pressure switches fail
Efficiency doesn’t eliminate risk—maintenance does.
🌬️ Section 4: Venting & Airflow — The Silent CO Contributors
Most CO issues trace back to venting problems, not the burner itself.
What Can Go Wrong:
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Snow, ice, or debris blocking PVC vents
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Rusted or disconnected metal flues
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Improper vent slope
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Backdrafting due to poor airflow
Homeowner Visual Checks (Safe Ones):
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Exterior vents clear of snow or nests
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No visible rust or corrosion
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Vent pipes firmly connected
If anything looks damaged or loose—stop and call a pro.
🔗 External reference:
https://www.rbastl.com/wp-content/uploads/sites/2/2019/08/Condensation-Brochure-for-Web.pdf
🧯 Section 5: The Heat Exchanger — Why Technicians Take It So Seriously
The heat exchanger separates:
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Combustion gases (dangerous)
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Household air (safe)
When It Fails:
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CO can mix with household air
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Symptoms may appear slowly
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Furnace may still “seem” to work
Warning Signs (Not Always Obvious):
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Persistent headaches when heat is running
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Soot or corrosion inside the furnace
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Unexplained CO alarm activations
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Furnace shutting down unexpectedly
Savvy clarity:
A cracked heat exchanger is not a DIY diagnosis. It requires professional inspection.
🔄 Section 6: Why Repeated Furnace Shutdowns Can Be a CO Warning
Safety systems exist for a reason.
If your furnace:
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Lights then shuts off
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Trips pressure switches repeatedly
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Short cycles frequently
…it may be reacting to unsafe combustion conditions.
Common Misstep:
Homeowners keep resetting the furnace instead of fixing the cause.
Savvy warning:
Repeated resets can mask a serious safety issue.
🏠 Section 7: Whole-Home Factors That Increase CO Risk
The furnace isn’t always acting alone.
Other Contributors:
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Poor home ventilation
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Sealed or renovated homes without combustion air upgrades
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Exhaust fans competing for air
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Other gas appliances malfunctioning
Carbon monoxide safety is a whole-home system, not a single-part issue.
🔗 External reference:
👉 https://www.epa.gov/indoor-air-quality-iaq/carbon-monoxides-impact-indoor-air-quality
🛠️ Section 8: What Homeowners Should Never Attempt
Some actions are dangerous no matter how confident you feel.
Never:
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Tape over CO detectors
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Bypass furnace safety switches
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Modify venting
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Ignore recurring CO alarms
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Assume “it’ll be fine until spring”
Savvy line in the sand:
Comfort problems can wait. Safety problems cannot.
📅 Section 9: Annual Maintenance Is a CO Safety Measure
Professional furnace maintenance isn’t just about efficiency.
It includes:
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Combustion analysis
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Heat exchanger inspection
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Venting verification
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Safety control testing
Skipping maintenance increases CO risk—plain and simple.
🔗 External reference:
https://www.energy.gov/energysaver/home-heating-systems
📞 Section 10: When to Call a Professional Immediately
Call for service right away if:
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A CO alarm has activated
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You smell exhaust fumes
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The furnace shuts down repeatedly
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You experience unexplained symptoms when heating runs
Choose a licensed, certified HVAC professional.
🧠 Savvy Final Takeaway: Safety Is Not Optional, Ever
Carbon monoxide doesn’t give warnings—it relies on you to have the right protections in place.
The good news?
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CO problems are preventable
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Detectors work
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Maintenance matters
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Early action saves lives
If there’s one furnace topic where Savvy never compromises, this is it.
