Can a Faulty HVAC Unit Release Carbon Monoxide?

HVAC carbon monoxide concerns are real. A malfunctioning gas furnace or other fuel-burning equipment can release carbon monoxide into your home. It is a colorless, odorless gas, and that is what makes it dangerous.

When everything is installed correctly and maintained properly, your HVAC system vents combustion gases safely outdoors. Problems start when a component fails, venting becomes blocked, or the system has not been serviced in a while.

Tiger Plumbing, Heating, Air Conditioning & Electrical has been serving Illinois homeowners since 1993. Our licensed HVAC technicians, plumbers, and electricians work together to make sure your systems operate safely, not just efficiently.

What Is Carbon Monoxide and How Does Your HVAC Create It?

Carbon monoxide forms when fuel like natural gas does not burn completely. You cannot see it or smell it, which is why it can build up without warning.

Any fuel-burning appliance produces carbon monoxide during normal operation, including:

Gas furnaces
Boilers
Gas water heaters
Gas fireplaces

An HVAC system that includes a gas furnace creates carbon monoxide as part of combustion. The system is designed to send that exhaust outside through flue pipes.

A central air conditioner does not create carbon monoxide. However, if a furnace carbon monoxide issue develops, the blower and ductwork can circulate contaminated air throughout the home.

How Can a Faulty HVAC Unit Release Carbon Monoxide?

Carbon monoxide leaks usually happen because something inside the system is worn out, damaged, or blocked.

Cracked Heat Exchanger in Your Furnace

The heat exchanger keeps combustion gases separate from the air that flows through your vents. Over time, metal can weaken from heat and corrosion. If cracks form, a carbon monoxide leak can allow exhaust gases to mix with the air moving through your home.

This is one of the most serious furnace problems because the crack may not be visible from the outside.

Blocked or Damaged Flue and Vent Pipes

Flue pipes carry exhaust gases outdoors. If they are blocked, rusted, disconnected, or improperly installed, gases can back up into living spaces.

Common causes include:

Bird nests
Debris buildup
Loose vent connections
Corroded sections of pipe

This is why annual inspections matter, especially before winter.

Improper Installation or DIY Changes

Incorrect gas pressure, loose venting connections, or improper slope on exhaust pipes can increase the risk of incomplete combustion.

Heating equipment should always be installed and adjusted by licensed professionals. Small setup mistakes can create larger safety issues later.

Poor Maintenance and Dirty Burners

When burners become dirty or safety controls fail, combustion can become incomplete. That increases carbon monoxide production.

Routine heating services help keep burners clean, venting clear, and safety switches operating as designed.

Can Your Air Conditioner Release Carbon Monoxide?

A typical electric air conditioner does not produce carbon monoxide. However, if CO from a furnace or water heater builds up in a basement or mechanical room, your HVAC system can move that air through the ductwork.

This is why both heating services and AC repair should include checks that ensure airflow and ventilation are functioning correctly.

Warning Signs of a Possible Carbon Monoxide Problem

Carbon monoxide does not have a smell. You cannot rely on scent alone.

Equipment or Home Clues

Yellow or flickering burner flames instead of steady blue

Rusted or loose vent pipes

Frequent furnace shutdowns

Excess condensation around windows

A system that struggles to stay running

Health Symptoms in People

Headaches or dizziness

Nausea

Confusion

Flu-like symptoms that improve when leaving the home

Multiple family members or pets feeling sick at the same time

If you suspect a carbon monoxide leak, leave the home immediately and contact emergency services.

How to Help Prevent Carbon Monoxide Leaks from Your HVAC

Most CO issues are preventable with routine care.

Schedule an annual furnace safety inspection before the heating season
Install carbon monoxide detectors on every level of your home
Keep furnace and water heater vents clear
Avoid using ovens or unvented heaters for heating
Call for service if your system behaves differently than usual

Joining Tiger’s Membership program helps ensure your equipment is checked regularly. Maintenance reduces wear and helps catch problems early.

If you believe your system is unsafe, contact us for Emergency hvac services right away.

Why Illinois Homeowners Trust Tiger for CO and Furnace Safety

Tiger Plumbing, Heating, Air Conditioning & Electrical has been serving Central and Eastern Illinois since 1993. We are veteran-owned and family-operated, with licensed professionals across HVAC, plumbing, and electrical trades.

Our team understands how systems work together. A furnace issue can affect airflow. Electrical controls affect safety. Ductwork influences how air moves through your home. We look at the full picture.

We serve families throughout Central and Eastern Illinois, and if a repair ends up being more than you planned for, financing options are available.

If you have concerns about carbon monoxide or your heating system has not been inspected recently, contact us today. A professional safety check provides clarity and helps ensure your home stays comfortable and safe.