As the temperature drops, we all rely on the heat produced by our furnaces to keep our homes warm and cozy. However, when the heat exchanger in your furnace becomes damaged, it can become a serious health hazard. 

Ravinia Plumbing, Sewer, Heating & Electric explains why a cracked heat exchanger is such a big deal as well as the signs of a cracked heat exchanger you need to watch for.

Why is it Important to Identify Cracks in the Heat Exchanger?

The heat exchanger is a vital component in your furnace that plays an important role in keeping your home warm and comfortable during the winter months. It works by transferring heat from the combustion process to the air that is circulated throughout your home.

As the combustion process takes place in the furnace, heat is generated which is then transferred into the heat exchanger. This heat exchanger consists of a series of metal tubes that are surrounded by air. The heat from the tubes is then transferred to the air, which is then blown through your home’s ductwork, providing warmth and comfort.

However, when the heat exchanger develops cracks, it can create a serious and dangerous problem. Not only can the cracks allow harmful gasses like carbon monoxide to leak into your home, but they can also cause the furnace to malfunction, resulting in a fire hazard.

Carbon monoxide is a colorless, odorless, lethal gas. Carbon monoxide poisoning symptoms include headaches, nausea, dizziness, and even death in severe cases. Therefore, it is essential to know the signs of a cracked heat exchanger and get it fixed immediately.

Cracks in the heat exchanger can occur due to a variety of factors, including age, overheating, and lack of maintenance. If not detected and repaired promptly, these cracks can become larger over time, leading to serious safety hazards for you and your family.

Signs of a Cracked Heat Exchanger

Let’s explore the signs of a cracked heat exchanger so you can quickly identify a problem with your furnace and have it professionally repaired before it’s too late.


Corrosion in the furnace or on the heat exchanger is one of the signs of a cracked heat exchanger that requires immediate attention. Moisture from the combustion process can lead to the formation of rust and corrosion throughout the furnace and on the metal surfaces of the heat exchanger, causing it to weaken or crack over time.

Soot Build-Up

The presence of soot or black residue inside your furnace is normal, but excessive build-up is an indicator of a problem. It could be a sign that your heat exchanger has cracks or leaks.

Unpleasant Odors

If you notice any strange, unpleasant odors, they could be signs of a cracked heat exchanger. A damaged heat exchanger can cause gas to escape and release an unusual chemical smell that is often described as similar to formaldehyde.

Furnace Flame Color

The color of the furnace flame can also help identify potential issues with the heat exchanger. If the flame is yellow rather than blue, this could be caused by a cracked heat exchanger.

Moisture Around Furnace

Moisture collecting around the furnace can be one of the warning signs of a cracked heat exchanger. If the heat exchanger is cracked, it can allow combustion gasses to escape and condense on the surrounding surfaces, leading to the accumulation of moisture. 

Carbon Monoxide Detector Alerts

All homes with gas furnaces should be equipped with a carbon monoxide detector to alert residents of potential leaks. If your carbon monoxide detector goes off, it indicates that the gas may be escaping from your heat exchanger. You should immediately evacuate the home and call for professional assistance to determine if a cracked heat exchanger is the source.

Call Ravinia Plumbing for Furnace Repair

If you notice any of the signs of a cracked heat exchanger mentioned above, don’t ignore them. It’s important to address the problem as soon as possible to protect your family’s health and safety. Contact Ravinia Plumbing for professional furnace repair service right away.

Ravinia Plumbing has a team of certified heating experts that provide reliable and efficient furnace repair services. We work with all types and brands of furnaces, and our team provides a quick and professional service that ensures the safety and comfort of your home. Contact us today to schedule an appointment in Chicago’s Northwest suburbs and Chicago’s North Shore.