A furnace is often a background player at home, ensuring you're warm across the cold winter months. It often doesn’t get noticed until a malfunction appears.
One cause may be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s worthwhile to learn the evidence of a cracked heat exchanger and what to 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 circulates through the ventilation. It typically does this through coils or tubes that heat up the air while acting as a barrier to keep the gasses 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 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 throughout your home.
For that reason, never turn on your furnace if you suspect you're dealing with a cracked heat exchanger, as letting it run could make the entire household sick. Contact an HVAC professional as soon as possible if you believe your furnace has a cracked heat exchanger that needs to be repaired.
Four Symptoms of a Cracked Heat Exchanger:
- Furnace turns off: Cracks in the heat exchanger can cause your furnace to shut off.
- Odd Smells: If the air escaping your furnace has a strong chemical smell, it might be evidence gas is seeping through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a common warning sign.
- Carbon monoxide alarm goes off or you recognize health problems: If a cracked heat exchanger is releasing carbon monoxide into your home, your carbon monoxide alarm should go off or household members might struggle with signs of carbon monoxide poisoning. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If the alarm goes off or you feel unwell, get out of the home immediately and then call for help.
- Soot: If you notice black sooty buildup around the exterior of your furnace, it’s an indication something may be seriously wrong.
What You Should Do if Your Furnace Heat Exchanger is Cracked
If you suspect your furnace has a cracked heat exchanger, hire a professional well versed in furnace installation right away so they can take a look at your system and, if necessary, perform a furnace heat exchanger replacement. Costs will fluctuate depending on the situation, but estimates often hover around $1,000 to $3,000.
Fortunately, the good news is that heat exchangers are regularly covered by the warranty. You’ll want to review the warranty paperwork on your furnace, since while the warranty won't always cover the entire cost of repairs, it can significantly reduce your bill.
How to Avoid a Cracked Heat Exchanger in Your Home
One of the most convenient ways to minimize the risk of problems in your furnace overall is via consistent furnace maintenance. Furnaces work the best when they run efficiently. Calling a trained professional to inspect your furnace for old parts, clogged filters and other potential problems can help you avoid getting a big bill later on.
It’s also helpful to review your furnace filters every few months – it’s encouraged some filters be changed 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 harder to accomplish its job. And the harder your furnace has to work, the more deterioration components like the heat exchanger will endure.