A furnace is usually a background player in your home, keeping you warm across the cold winter months. It frequently doesn’t get noticed until something breaks down. 

One cause might be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s worthwhile to learn the evidence of a cracked heat exchanger and what to do if you are worried that may be the problem.  

What Is a Heat Exchanger in a Furnace? 

A heat exchanger transfers heat from the combustion chamber inside your furnace to the air that moves throughout the air ducts. It usually handles this through coils or tubes that warm the air while functioning as a barrier to keep byproducts created in the combustion chamber, called flue gasses, from leaking out into your home.  

Is a Cracked Heat Exchanger Dangerous? 

Because of its important role, it’s no surprise that a damaged heat exchanger can pose a risk. Cracks in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to flow through your home. 

For obvious reasons, don't ever turn on your furnace if you believe you're dealing with a cracked heat exchanger, as letting it run could make the whole household ill. Reach out to an HVAC professional immediately if you believe your heating has a cracked heat exchanger that should be repaired. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace switches off: A crack in your heat exchanger could cause your furnace to switch off. 
  • Unusual Smells: If the air coming out of your furnace has an intense chemical scent, it might be evidence gasses are leaking through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a significant warning sign. 
  • Carbon monoxide alarm is triggered or you feel symptoms of poisoning: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm should go off or family members might start experiencing signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If an alarm goes off or you feel sick, get out of the home as soon as you can and then call for help. 
  • Soot: If you spot black sooty collecting on the exterior of your furnace, it’s more evidence something may be seriously wrong.

What You Should Do if the Furnace Heat Exchanger is Cracked 

If you suspect your furnace has a cracked heat exchanger, contact a professional well versed in furnace installation Manassas as soon as possible so they can inspect your system and, if necessary, handle a furnace heat exchanger replacement. Costs often differ 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. You should confirm the warranty paperwork on your furnace, as while the warranty might not cover the entire cost of repairs, it could significantly reduce your bill.  

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the best ways to prevent a problem in your furnace overall is through consistent furnace maintenance. Furnaces work the best when they run efficiently. Hiring a trained professional to examine your furnace for worn-out parts, clogged filters and other common problems can keep you from getting a big bill later on.  

It’s also a good idea to review 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 drawing air through a clogged filter makes the entire furnace work longer to complete its job. And the harder your furnace needs to run, the more deterioration parts like the heat exchanger will experience.