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AW Heating & Cooling Blog

Know the Signs of a Cracked Heat Exchanger


As winter settles in and we rely on our trusty heating systems to keep us warm, there’s a hidden danger that often goes unnoticed. It’s the cracked heat exchanger. This important part plays a big role in your furnace’s operation and a crack can lead to a range of problems.

Some of those problems are not only inconvenient but also potentially hazardous. Many demand prompt furnace services in Sylvania, OH. Let’s look into the situation behind a cracked heat exchanger and how to identify it.

Understanding the Heat Exchanger

Inside your furnace, the fuel source undergoes combustion to produce hot gases. These gases contain a large amount of thermal energy. The heat exchanger is a metal component with a series of tubes or coils. As the hot combustion gases flow through these tubes or coils, their thermal energy is transferred to the metal surface of the heat exchanger.

While this happens, the blower or fan in the furnace pushes air over the exterior surface of the heat exchanger. The metal heats up and this warmth is transferred to the air without the two substances coming into direct contact. The now-warmed air is then distributed through the ductwork in your home.

Odd Odors

One of the most noticeable signs of a cracked heat exchanger is the presence of unusual odors. If you detect a metallic, burning smell or the smell of rotten eggs or sulfur when your furnace is running, these odors could be an indication that the heat exchanger has developed a crack that is allowing gases to escape. 

One of these gases is carbon monoxide. It is a colorless, odorless gas that poses a severe health risk. Modern homes are equipped with CO detectors and if yours goes off unexpectedly it’s a red flag. Turn off your furnace, leave your home, and contact a professional as soon as possible.


If the heat exchanger develops cracks or other defects, it can compromise this separation and potentially allow harmful gases to enter your living space. This is why regular inspection and maintenance of the heat exchanger are both important which we’ll perform during maintenance.

Inconsistent Heat

A cracked heat exchanger can disrupt the proper functioning of your furnace, resulting in uneven heating throughout your home. If you find some rooms warmer than others or notice an overall decline in heating efficiency, it’s time to have your system inspected.

Strange Noises

While some level of noise is normal, any new or unusual sounds coming from your furnace should be investigated. Hissing, popping, or banging noises could indicate a cracked heat exchanger. Escaping gases disrupt the usual combustion process.

As the winter months unfold, staying warm and safe is a top priority. Understanding the signs of a cracked heat exchanger empowers you to take proactive measures and make sure that your heating system operates efficiently and safely. If you notice any of these warning signs, don’t hesitate to reach out to a qualified HVAC professional for a thorough inspection. 

The silent danger of a cracked heat exchanger is best addressed before it turns into an emergency. Stay warm, stay safe! Contact AW Heating & Cooling today!

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