A furnace is often a background player at home, keeping you warm across the cold winter months. It regularly won't be noticed until something goes wrong. 

One root cause might be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s critical to know the evidence of a cracked heat exchanger and what to 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 of your furnace to the air that circulates through the ventilation. It typically does this with coils or tubes that heat up the air while serving as a barrier to keep gas produced in the combustion chamber, called flue gasses, from leaking out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Thanks to its important role, it shouldn't come as a surprise that a cracked heat exchanger can be hazardous. A crack in the heat exchanger can enable dangerous gasses – like carbon monoxide, which can be lethal – to flow throughout your home. 

For this reason, do NOT turn on your heating if you believe it has a cracked heat exchanger, as letting it run could make your entire household ill. Contact an HVAC professional immediately if you believe your heating has a cracked heat exchanger that needs repair. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace switches off: A crack in your heat exchanger can cause your furnace to turn off. 
  • Odd Smells: If the air escaping your furnace has an intense chemical scent, it may be a sign gasses are slipping through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a major warning sign. 
  • Carbon monoxide alarm goes off or you feel symptoms of poisoning: If a cracked heat exchanger is emitting carbon monoxide in your home, your carbon monoxide alarm should go off or family members could start experiencing signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel unusually tired, exit the home right away and then call for help. 
  • Soot: If you see black sooty accumulating on the exterior of your furnace, it’s another sign something could be seriously wrong.

What You Can Do if Your Furnace Heat Exchanger is Cracked 

If you suspect your furnace has a cracked heat exchanger, hire a professional with extensive experience in furnace installation Sandpoint right away so they can inspect your system and, if required, handle a furnace heat exchanger replacement. Costs often fluctuate depending on the situation, but estimates can roughly suggest $1,000 to $3,000. 

However, the good news is that heat exchangers are generally covered by the warranty. It's a good idea to review the warranty paperwork on your furnace, because while the warranty might not 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 through regular furnace maintenance. Furnaces offer the most benefits when they work efficiently. Contacting a certified professional to check your furnace for worn-out parts, dirty filters and other common problems can keep you from getting a big bill later on.  

It’s also beneficial to inspect your furnace filters every few months – it’s recommended some filters be swapped out 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 dragging air through a clogged filter makes your entire furnace work harder to accomplish its job. And the harder your furnace needs to run, the more wear and tear parts like the heat exchanger will sustain.