A furnace is almost always a background player in your home, keeping you warm across the cold winter months. It frequently won't be noticed until a malfunction appears. 

One root cause may be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s critical to learn the signs of a cracked heat exchanger and what to do if you suspect that might be the problem.  

What Is a Heat Exchanger in a Furnace? 

A heat exchanger helps transition heat from the combustion chamber inside your furnace to the air that circulates inside the ventilation. It usually accomplishes this through coils or tubes that warm the air while serving as a barrier to keep the gasses produced in the combustion chamber, called flue gasses, from escaping out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Given its central role, it’s no surprise that a cracked heat exchanger can pose a risk. Cracks in the heat exchanger can permit dangerous gasses – like carbon monoxide, which can be lethal – to be distributed throughout your home. 

For obvious reasons, do NOT turn on your heater if you suspect there's a crack in the heat exchanger, as letting it run could make the entire household ill. Contact an HVAC professional right away if you think your heating has a cracked heat exchanger that needs repair. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace turns off: Cracks in the heat exchanger could cause your furnace to switch off. 
  • Unusual Smells: If the air coming out of your furnace has an intense chemical smell, it could be a sign gas is leaking through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm is triggered or you notice poisoning symptoms: If a cracked heat exchanger is relieving carbon monoxide inside your home, your carbon monoxide alarm could go off or household members may start experiencing signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If an alarm goes off or you feel unusually tired, get out of the home immediately and then call for help. 
  • Soot: If you notice black sooty collecting near the exterior of your furnace, it’s an indication something may be seriously wrong.

What You Should Do if a Furnace Heat Exchanger is Cracked 

If you believe your furnace has a cracked heat exchanger, contact a pro with extensive experience in furnace installation Auburn right away so they can inspect your system and, if needed, handle a furnace heat exchanger replacement. Costs should differ depending on the situation, but estimates often hover around $1,000 to $3,000. 

However, the good news is that heat exchangers are regularly covered by the warranty. You should review the warranty paperwork on your furnace, since while the warranty won't always cover the entire cost of repairs, it can significantly reduce your bill.  

How to Avoid a Cracked Heat Exchanger in Your Home  

One of the easiest ways to avoid problems in your furnace overall is with regular furnace maintenance. Furnaces work the best when they operate efficiently. Contacting a certified professional to inspect your furnace for worn-out parts, dirty filters and other common problems can help you avoid getting a big bill later on.  

It’s also a good idea to take a look at your furnace filters every few months – it’s encouraged some filters be replaced every 90 days or sooner if they are dirty or grimy. While the filters aren't a part of the heat exchanger itself, the strain of drawing air through a clogged filter makes the entire furnace work longer to do its job. And the harder your furnace has to work, the more wear and tear parts like the heat exchanger will sustain.