Cracked Heat Exchanger: What That Means and What to Do Next

September 20, 2022

A furnace is almost always a background player at home, ensuring you're warm during the cold winter months. It frequently won't be noticed until a malfunction appears.

One cause could be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s critical to familiarize yourself with the evidence of a cracked heat exchanger and what you should 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 throughout the ventilation. It typically handles this with coils or tubes that heat up the air while acting as a barrier to keep the gasses formed in the combustion chamber, called flue gasses, from leaking out into your home.

Is a Cracked Heat Exchanger Dangerous?

Because of its central role, it shouldn't come as a surprise that a damaged heat exchanger can pose a risk. Cracks in the heat exchanger can allow dangerous gasses – including carbon monoxide, which can be lethal – to circulate through your home.

For this reason, do NOT run your furnace if you suspect you're dealing with a cracked heat exchanger, as letting it run could make the whole household sick. Call an HVAC professional as soon as possible if you think your furnace has a cracked heat exchanger that should be repaired.

Four Symptoms 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 coming out of your furnace has a strong chemical scent, it might be a sign gasses are leaking through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a common warning sign.
  • Carbon monoxide alarm initiates or you recognize poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide in your home, your carbon monoxide alarm may go off or family members could struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel unusually tired, exit the home as soon as you can and then call for help.
  • Soot: If you spot black sooty accumulating near the exterior of your furnace, it’s another sign something might be seriously wrong.

What You Should Do if a Furnace Heat Exchanger is Cracked

If you worry your furnace has a cracked heat exchanger, contact a professional with extensive experience in furnace installation Lawrence as soon as possible so they can examine your system and, if needed, handle a furnace heat exchanger replacement. Costs will 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 protected by the warranty. It's a good idea to review the warranty paperwork on your furnace, because while the warranty may not cover the entire cost of repairs, it could significantly lower 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 with routine furnace maintenance. Furnaces offer the most benefits when they run efficiently. Hiring a trained professional to check your furnace for broken-down parts, clogs in the air filters and other likely 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 recommended 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 the entire furnace work longer to complete its job. And the harder your furnace works, the more wear and tear components like the heat exchanger will sustain.