A furnace is usually a background player in your home, keeping you warm across the cold winter months. It often isn't noticed until something breaks down. 

One root cause could be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s worthwhile to know the evidence of a cracked heat exchanger and what you can do if you suspect that is the problem.  

What Is a Heat Exchanger in a Furnace? 

A heat exchanger helps move heat from the combustion chamber of your furnace to the air that moves inside the ventilation. It typically does this through coils or tubes that heat the air while serving as a barrier to keep byproducts produced 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 isn't surprising that a broken heat exchanger can pose a risk. A damaged heat exchanger can allow dangerous gasses – such as carbon monoxide, which can be lethal – to be distributed across your home. 

For this reason, never turn on your heater if you believe there's a crack in the heat exchanger, as doing so could make the whole family ill. Call an HVAC professional as soon as possible if you believe your heating has a cracked heat exchanger that should be repaired. 

Four Signs of a Cracked Heat Exchanger: 

  • Furnace shuts off: A crack in your heat exchanger can cause your furnace to shut off. 
  • Odd Smells: If the air leaving your furnace has a powerful chemical odor, it might be evidence gasses are seeping through cracks in your heat exchanger. These byproducts, which will often smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm goes off or you recognize symptoms of poisoning: If a cracked heat exchanger is releasing carbon monoxide in your home, your carbon monoxide alarm could go off or household members might experience signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If the alarm goes off or you feel sick, get out of the home right away and then call for help. 
  • Soot: If you spot black sooty accumulating near the exterior of your furnace, it’s an indication something may be seriously wrong.

What to Do if Your Furnace Heat Exchanger is Cracked 

If you suspect your furnace has a cracked heat exchanger, call a pro experienced in furnace installation Cache Valley as soon as possible so they can examine your system and, if required, perform a furnace heat exchanger replacement. Costs should differ depending on the situation, but estimates often hover around $1,000 to $3,000. 

Estimates aside, the good news is that heat exchangers are generally covered by the warranty. It's a good idea to check the warranty paperwork on your furnace, since while the warranty might not cover the entire cost of repairs, it could 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 through consistent furnace maintenance. Furnaces work the best when they run efficiently. Contacting a trained professional to inspect your furnace for broken-down parts, dirty filters and other potential problems can keep you from getting a big bill later on.  

It’s also helpful to inspect your furnace filters every few months – it’s ideal some filters be replaced 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 longer to do its job. And the harder your furnace needs to run, the more strain pieces like the heat exchanger will endure.