Cracked Heat Exchanger: What It Means and What You Should Do Next

September 20, 2022

A furnace is often a background player for your home, helping keep you warm across the cold winter months. It frequently isn't noticed until something goes wrong.

One cause may be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s critical to learn the signs 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 in your furnace to the air that circulates inside the system. It generally does this using 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’s no surprise that a cracked heat exchanger can be very dangerous. A crack in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to flow across your home.

For that reason, do NOT use your heater if you believe it has a cracked heat exchanger, as doing so could make your entire family ill. Call an HVAC professional as soon as possible if you are worried your heater has a cracked heat exchanger that needs to be repaired.

Four Warning Signs of a Cracked Heat Exchanger:

  • Furnace turns off: A cracked heat exchanger can cause your furnace to switch off.
  • Odd Smells: If the air escaping your furnace has a powerful chemical smell, it may be a sign gasses are leaking through cracks in your heat exchanger. These gasses, which may smell like formaldehyde, are a major warning sign.
  • Carbon monoxide alarm is triggered or you recognize health problems: If a cracked heat exchanger is emitting carbon monoxide inside your home, your carbon monoxide alarm may go off or household members might struggle with signs of carbon monoxide poisoning. Symptoms 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 find black sooty buildup on the exterior of your furnace, it’s an indication something could be seriously wrong.

What to Do if the Furnace Heat Exchanger is Cracked

If you suspect your furnace has a cracked heat exchanger, hire a professional with extensive experience in furnace installation Stuart as soon as possible so they can examine your system and, if necessary, perform a furnace heat exchanger replacement. Costs will 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 often covered by the warranty. You should confirm the warranty paperwork on your furnace, because while the warranty might not cover the entire cost of repairs, it could significantly lower your bill.

How to Avoid a Cracked Heat Exchanger in Your Home

One of the easiest ways to minimize the risk of problems in your furnace overall is via regular furnace maintenance. Furnaces provide the best possible return on investment when they run efficiently. Contacting a skilled professional to inspect your furnace for worn-out parts, clogged filters and other potential 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 changed every 90 days or sooner if they are dirty or grimy. While the filters aren't a part of the heat exchanger itself, the strain of pulling air through a clogged filter makes the entire furnace work longer to do its job. And the harder your furnace needs to run, the more strain components like the heat exchanger will experience.