A furnace is usually a background player at home, helping keep you warm across the cold winter months. It frequently doesn’t get noticed until something breaks down.
One root cause may be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s important to know the symptoms 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 inside your furnace to the air that flows inside the air ducts. It generally handles this via coils or tubes that warm the air while functioning as a barrier to keep byproducts formed in the combustion chamber, called flue gasses, from escaping out into your home.
Is a Cracked Heat Exchanger Dangerous?
Given its central role, it isn't surprising that a damaged heat exchanger can pose a risk. Cracks in the heat exchanger can permit dangerous gasses – such as carbon monoxide, which can be lethal – to circulate throughout your home.
For obvious reasons, don't ever use your heater if you suspect there's a crack in the heat exchanger, as this could make the whole household ill. Reach out to an HVAC professional immediately if you are worried your heater has a cracked heat exchanger that needs to be repaired.
Four Signs of a Cracked Heat Exchanger:
- Furnace switches off: Cracks in the heat exchanger may cause your furnace to shut off.
- Strange Smells: If the air leaving your furnace has an intense chemical odor, it may be evidence gas is leaking through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a major warning sign.
- Carbon monoxide alarm goes off or you notice health problems: If a cracked heat exchanger is emitting carbon monoxide into your home, your carbon monoxide alarm should go off or family members might experience signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If your alarm goes off or you feel unwell, exit the home as soon as you can and then call for help.
- Soot: If you find black sooty accumulating around the exterior of your furnace, it’s another sign something might be seriously wrong.
What to Do if a Furnace Heat Exchanger is Cracked
If you worry your furnace has a cracked heat exchanger, hire a pro well versed in furnace installation right away so they can inspect your system and, if required, perform a furnace heat exchanger replacement. Costs will vary depending on the situation, but estimates can roughly suggest $1,000 to $3,000.
Estimates aside, the good news is that heat exchangers are regularly included in the warranty. You should check the warranty paperwork on your furnace, because while the warranty may not cover the entire cost of repairs, it can significantly reduce your bill.
How to Prevent a Cracked Heat Exchanger in Your Home
One of the most convenient ways to prevent a problem in your furnace overall is with consistent furnace maintenance. Furnaces work the best when they run efficiently. Contacting a certified professional to inspect 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 ideal some filters be replaced 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 do its job. And the harder your furnace needs to run, the more strain parts like the heat exchanger will experience.
