A furnace is often a background player in your home, ensuring you're warm across the cold winter months. It often won't be noticed until something breaks down.
One cause may be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s important to know the signs of a cracked heat exchanger and what to do if you suspect 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 flows inside the ventilation. It generally handles this through coils or tubes that heat up the air while acting as a barrier to keep byproducts formed in the combustion chamber, called flue gasses, from getting out into your home.
Is a Cracked Heat Exchanger Dangerous?
Given its important role, it’s no surprise that a cracked heat exchanger can be very dangerous. A damaged heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to circulate through your home.
For obvious reasons, don't ever run your heater if you suspect there's a crack in the heat exchanger, as letting it run could make the whole family ill. Reach out to an HVAC professional as soon as possible if you think your heating has a cracked heat exchanger that needs repair.
Four Signs of a Cracked Heat Exchanger:
- Furnace switches off: A crack in your heat exchanger may cause your furnace to turn off.
- Strange Smells: If the air escaping your furnace has a strong chemical scent, it may be a sign gasses are seeping through cracks in your heat exchanger. These byproducts, which will often smell like formaldehyde, are a significant warning sign.
- Carbon monoxide alarm is triggered or you recognize health problems: If a cracked heat exchanger is relieving carbon monoxide inside your home, your carbon monoxide alarm could go off or family members may 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 unusually tired, leave the home immediately and then call for help.
- Soot: If you notice black sooty buildup near the exterior of your furnace, it’s an indication something might be seriously wrong.
What You Can Do if Your Furnace Heat Exchanger is Cracked
If you suspect your furnace has a cracked heat exchanger, call a professional with extensive experience in furnace installation as soon as possible so they can take a look at your system and, if necessary, perform a furnace heat exchanger replacement. Costs will differ depending on the situation, but estimates can roughly suggest $1,000 to $3,000.
Fortunately, 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 may 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 most convenient ways to avoid problems in your furnace overall is via routine furnace maintenance. Furnaces provide the best possible return on investment when they work efficiently. Contacting a certified professional to check your furnace for worn-out parts, clogged filters and other potential problems can help you avoid getting a big bill later on.
It’s also helpful to take a look at your furnace filters every few months – it’s encouraged some filters be replaced every 90 days or sooner if they are dirty or grimy. While the filters aren't connected to the heat exchanger itself, the strain of drawing air through a clogged filter makes the entire furnace work harder to complete its job. And the harder your furnace needs to run, the more strain pieces like the heat exchanger will experience.