A furnace is usually a background player at home, keeping you warm in the cold winter months. It frequently isn't noticed until a malfunction appears. 

One cause could be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s critical to learn the evidence of a cracked heat exchanger and what you should do if you are worried that might be the problem.  

What Is a Heat Exchanger in a Furnace? 

A heat exchanger transfers heat from the combustion chamber in your furnace to the air that flows inside the ventilation. It typically handles this through coils or tubes that heat the air while functioning as a barrier to keep byproducts formed in the combustion chamber, called flue gasses, from leaking out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Because of its key role, it’s no surprise that a damaged heat exchanger can be very dangerous. A damaged heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to flow throughout your home. 

For that reason, never run your furnace if you suspect you're dealing with a cracked heat exchanger, as this could make the whole household ill. Call an HVAC professional as soon as possible if you are worried your heater has a cracked heat exchanger that needs repair. 

Four Signs of a Cracked Heat Exchanger: 

  • Furnace shuts off: A crack in your heat exchanger can cause your furnace to switch off. 
  • Unusual Smells: If the air leaving your furnace has a strong chemical odor, it may be evidence gas is leaking through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm initiates or you recognize health problems: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm could go off or family members may experience signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If an alarm goes off or you feel unwell, leave the home right away and then call for help. 
  • Soot: If you notice black sooty collecting on the exterior of your furnace, it’s an indication something could be seriously wrong.

What You Can Do if Your Furnace Heat Exchanger is Cracked 

If you worry your furnace has a cracked heat exchanger, hire a pro with extensive experience in furnace installation Manassas right away so they can take a look at your system and, if needed, perform a furnace heat exchanger replacement. Costs should differ depending on the situation, but estimates can roughly suggest $1,000 to $3,000. 

Estimates aside, the good news is that heat exchangers are regularly covered by the warranty. It's a good idea to confirm the warranty paperwork on your furnace, as while the warranty won't always cover the entire cost of repairs, it can significantly lower your bill.  

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the most convenient ways to prevent a problem in your furnace overall is with consistent furnace maintenance. Furnaces work the best when they work efficiently. Hiring a skilled professional to inspect your furnace for worn-out parts, clogs in the air filters and other potential problems can help you avoid getting a big bill later on.  

It’s also beneficial to inspect your furnace filters every few months – it’s recommended some filters be changed every 90 days or sooner if they are dirty or grimy. While the filters are not part of the heat exchanger itself, the strain of pulling air through a clogged filter makes your entire furnace work more vigorously to do its job. And the harder your furnace needs to run, the more strain pieces like the heat exchanger will experience.