A furnace is often a background player for your home, ensuring you're warm across the cold winter months. It often doesn’t get noticed until something goes wrong.
One root cause might be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s worthwhile to know the signs of a cracked heat exchanger and what you should do if you suspect that might be the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger helps transition heat from the combustion chamber inside your furnace to the air that moves through the system. It generally does this with coils or tubes that heat up the air while serving as a barrier to keep the gasses created in the combustion chamber, called flue gasses, from getting out into your home.
Is a Cracked Heat Exchanger Dangerous?
Because of its important role, it isn't surprising that a broken heat exchanger can be hazardous. A crack in the heat exchanger can allow dangerous gasses – like carbon monoxide, which can be lethal – to circulate across your home.
For that reason, never use your heater if you suspect there's a crack in the heat exchanger, as this could make the entire family ill. Call an HVAC professional right away if you think your furnace has a cracked heat exchanger that needs to be repaired.
Four Warning Signs of a Cracked Heat Exchanger:
- Furnace shuts off: A cracked heat exchanger could cause your furnace to shut off.
- Odd Smells: If the air leaving your furnace has a strong chemical scent, it may be an indicator that gas is slipping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a significant warning sign.
- Carbon monoxide alarm is triggered or you notice poisoning symptoms: If a cracked heat exchanger is emitting carbon monoxide in your home, your carbon monoxide alarm could go off or household members could experience signs of carbon monoxide poisoning. Symptoms 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 see black sooty accumulating around the exterior of your furnace, it’s an indication something may be seriously wrong.
What to Do if the Furnace Heat Exchanger is Cracked
If you believe your furnace has a cracked heat exchanger, contact a pro with extensive experience in furnace installation right away so they can take a look at your system and, if required, perform a furnace heat exchanger replacement. Costs will vary depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000.
Fortunately, the good news is that heat exchangers are generally protected by the warranty. You’ll want to review the warranty paperwork on your furnace, since while the warranty might not cover the entire cost of repairs, it could significantly shrink your bill.
How to Avoid a Cracked Heat Exchanger in Your Home
One of the easiest ways to avoid problems in your furnace overall is via routine furnace maintenance. Furnaces offer the most benefits when they work efficiently. Calling a certified professional to inspect your furnace for broken-down parts, dirty filters and other potential problems can help you avoid getting a big bill later on.
It’s also beneficial to review your furnace filters every few months – it’s ideal 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 dragging air through a clogged filter makes your entire furnace work more vigorously to accomplish its job. And the harder your furnace works, the more strain components like the heat exchanger will experience.