A furnace is often a background player at home, helping keep you warm during the cold winter months. It regularly won't be noticed until a malfunction appears.
One cause might be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s critical to familiarize yourself with the symptoms of a cracked heat exchanger and what you can do if you believe that might be the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger helps transition heat from the combustion chamber in your furnace to the air that moves inside the air ducts. It typically handles this through coils or tubes that heat the air while serving as a barrier to keep byproducts created in the combustion chamber, called flue gasses, from escaping out into your home.
Is a Cracked Heat Exchanger Dangerous?
Because of its important role, it’s no surprise that a broken heat exchanger can be hazardous. Cracks in the heat exchanger can allow dangerous gasses – such as carbon monoxide, which can be lethal – to be distributed through your home.
For that reason, do NOT run your heater if you believe you're dealing with a cracked heat exchanger, as this could make the whole family ill. Reach out to an HVAC professional as soon as possible if you are worried your furnace has a cracked heat exchanger that should be repaired.
Four Symptoms of a Cracked Heat Exchanger:
- Furnace switches off: A cracked heat exchanger may cause your furnace to turn off.
- Odd Smells: If the air coming out of your furnace has a strong chemical smell, it may be an indicator that gasses are seeping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a significant warning sign.
- Carbon monoxide alarm goes off or you notice poisoning symptoms: If a cracked heat exchanger is releasing carbon monoxide into your home, your carbon monoxide alarm should go off or family members might experience signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If the alarm goes off or you feel unusually tired, leave the home as soon as you can and then call for help.
- Soot: If you notice black sooty collecting around 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 believe your furnace has a cracked heat exchanger, call a pro well versed in furnace installation as soon as possible so they can examine your system and, if needed, handle a furnace heat exchanger replacement. Costs often fluctuate 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 protected by the warranty. You’ll want to check the warranty paperwork on your furnace, as while the warranty might not cover the entire cost of repairs, it can significantly shrink your bill.
How to Avoid a Cracked Heat Exchanger in Your Home
One of the most convenient ways to prevent a problem in your furnace overall is with routine furnace maintenance. Furnaces offer the most benefits when they work efficiently. Contacting a trained professional to check your furnace for broken-down parts, clogs in the air 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 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 pulling air through a clogged filter makes the entire furnace work harder to accomplish its job. And the harder your furnace has to work, the more strain pieces like the heat exchanger will experience.