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

One source could be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s critical to familiarize yourself with the signs of a cracked heat exchanger and what you can do if you are worried that is 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 inside the air ducts. It typically accomplishes this with coils or tubes that heat the air while serving as a barrier to keep gas formed 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 isn't surprising that a broken heat exchanger can pose a risk. A damaged heat exchanger can allow dangerous gasses – including carbon monoxide, which can be lethal – to be distributed through your home. 

For obvious reasons, don't ever run your heater if you think there's a crack in the heat exchanger, as this could make the entire family sick. Call an HVAC professional immediately if you are worried your heating has a cracked heat exchanger that should be repaired. 

Four Warning Signs of a Cracked Heat Exchanger: 

  • Furnace turns off: Cracks in the heat exchanger may cause your furnace to turn off. 
  • Odd Smells: If the air leaving your furnace has an intense chemical smell, it might be an indicator that gasses are leaking through cracks in your heat exchanger. These gasses, which will often smell like formaldehyde, are a common warning sign. 
  • Carbon monoxide alarm is triggered or you notice poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide inside your home, your carbon monoxide alarm may go off or household members could experience signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling sleepy. If an alarm goes off or you feel unwell, get out of the home immediately and then call for help. 
  • Soot: If you spot black sooty accumulating near the exterior of your furnace, it’s more evidence something may be seriously wrong.

What to Do if a Furnace Heat Exchanger is Cracked 

If you believe your furnace has a cracked heat exchanger, call a professional experienced in furnace installation Richmond right away so they can inspect your system and, if required, start a furnace heat exchanger replacement. Costs should differ depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000. 

Fortunately, the good news is that heat exchangers are generally protected by the warranty. It's a good idea to confirm the warranty paperwork on your furnace, since while the warranty might not cover the entire cost of repairs, it still may significantly reduce your bill.  

How to Prevent a Cracked Heat Exchanger in Your Home  

One of the best ways to avoid problems in your furnace overall is with consistent furnace maintenance. Furnaces work the best when they work efficiently. Hiring a certified professional to check your furnace for old parts, dirty filters and other potential problems can help you avoid getting a big bill later on.  

It’s also beneficial to review 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 do its job. And the harder your furnace works, the more strain pieces like the heat exchanger will sustain.