A furnace is almost always a background player in your home, ensuring you're warm during the cold winter months. It regularly doesn’t get noticed until a malfunction appears.
One cause might be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s worthwhile to learn the signs of a cracked heat exchanger and what to do if you suspect that might be the problem.
What Is a Heat Exchanger in a Furnace?
A heat exchanger transfers heat from the combustion chamber of your furnace to the air that moves throughout the ventilation. It generally accomplishes this via coils or tubes that heat up the air while functioning as a barrier to keep gas formed in the combustion chamber, called flue gasses, from getting 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 pose a risk. A crack in the heat exchanger can enable dangerous gasses – including carbon monoxide, which can be lethal – to circulate through your home.
For this reason, never use your heating if you suspect you're dealing with a cracked heat exchanger, as doing so could make your entire family ill. Contact an HVAC professional immediately if you believe your heating has a cracked heat exchanger that needs repair.
Four Warning Signs of a Cracked Heat Exchanger:
- Furnace switches off: Cracks in the heat exchanger could cause your furnace to switch off.
- Odd Smells: If the air coming out of your furnace has a strong chemical scent, it might be evidence gas is leaking through cracks in your heat exchanger. These gasses, which will often smell like formaldehyde, are a significant warning sign.
- Carbon monoxide alarm initiates or you notice poisoning symptoms: If a cracked heat exchanger is relieving carbon monoxide inside your home, your carbon monoxide alarm should go off or household members may struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If your alarm goes off or you feel unusually tired, leave the home as soon as you can and then call for help.
- Soot: If you find black sooty accumulating on the exterior of your furnace, it’s an indication something could be seriously wrong.
What You Can Do if Your Furnace Heat Exchanger is Cracked
If you believe your furnace has a cracked heat exchanger, contact a pro with extensive experience in furnace installation as soon as possible so they can inspect your system and, if required, start 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 generally covered by the warranty. You’ll want to review the warranty paperwork on your furnace, since while the warranty may not cover the entire cost of repairs, it still may significantly reduce your bill.
How to Prevent a Cracked Heat Exchanger in Your Home
One of the easiest ways to prevent a problem in your furnace overall is with routine furnace maintenance. Furnaces offer the most benefits when they operate efficiently. Calling a certified professional to check your furnace for broken-down parts, clogs in the air filters and other common problems can help you avoid getting a big bill later on.
It’s also beneficial to inspect your furnace filters every few months – it’s encouraged some filters be swapped out 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 pulling air through a clogged filter makes the entire furnace work longer to complete its job. And the harder your furnace works, the more wear and tear components like the heat exchanger will experience.