A furnace is often a background player at home, keeping you warm during the cold winter months. It often doesn’t get noticed until a malfunction appears. 

One cause could be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s worthwhile to learn the evidence of a cracked heat exchanger and what you should do if you suspect that is 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 circulates inside the air ducts. It generally handles this via coils or tubes that warm the air while functioning as a barrier to keep byproducts formed in the combustion chamber, called flue gasses, from escaping out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Given its important role, it shouldn't come as a surprise that a broken heat exchanger can be very dangerous. A damaged heat exchanger can allow dangerous gasses – including carbon monoxide, which can be lethal – to be distributed through your home. 

For that reason, never use your heating if you believe it has a cracked heat exchanger, as this could make your entire household ill. Contact an HVAC professional right away if you think your heater has a cracked heat exchanger that should be repaired. 

Four Signs of a Cracked Heat Exchanger: 

  • Furnace switches off: A cracked heat exchanger could cause your furnace to switch off. 
  • Unusual Smells: If the air leaving your furnace has a strong chemical scent, it might be an indicator that gasses are leaking through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm initiates or you notice poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide in your home, your carbon monoxide alarm may go off or household members could struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If an alarm goes off or you feel unusually tired, get out of the home as soon as you can and then call for help. 
  • Soot: If you notice black sooty collecting near the exterior of your furnace, it’s another sign something may be seriously wrong.

What You Should Do if the Furnace Heat Exchanger is Cracked 

If you believe your furnace has a cracked heat exchanger, hire a professional well versed in furnace installation Norco and St. Charles Parish as soon as possible so they can examine your system and, if necessary, perform a furnace heat exchanger replacement. Costs will vary depending on the situation, but estimates can roughly suggest $1,000 to $3,000. 

Fortunately, the good news is that heat exchangers are generally included in the warranty. You should check the warranty paperwork on your furnace, because while the warranty won't always cover the entire cost of repairs, it still may significantly reduce your bill.  

How to Avoid a Cracked Heat Exchanger in Your Home  

One of the easiest ways to prevent a problem in your furnace overall is via regular furnace maintenance. Furnaces provide the best possible return on investment when they operate efficiently. Contacting a skilled professional to examine your furnace for old parts, clogs in the air filters and other likely 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 encouraged some filters be swapped out every 90 days or sooner if they are dirty or grimy. While the filters aren't connected to the heat exchanger itself, the strain of pulling air through a clogged filter makes the entire furnace work longer to do its job. And the harder your furnace needs to run, the more wear and tear pieces like the heat exchanger will endure.