A furnace is often a background player for your home, ensuring you're warm across the cold winter months. It regularly doesn’t get noticed until a malfunction appears.
One root cause could be that your furnace has a cracked heat exchanger. It’s a potentially dangerous issue, so it’s important 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 helps transition heat from the combustion chamber in your furnace to the air that circulates inside the air ducts. It usually handles this using coils or tubes that heat the air while functioning 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 central role, it’s no surprise that a cracked heat exchanger can pose a risk. Cracks in the heat exchanger can permit dangerous gasses – such as carbon monoxide, which can be lethal – to flow through your home.
For this reason, never turn on your heater if you suspect there's a crack in the heat exchanger, as letting it run could make the entire household sick. Call 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 shuts off: A cracked heat exchanger can cause your furnace to turn off.
- Unusual Smells: If the air escaping your furnace has an intense chemical smell, it could be an indicator that gas is seeping through cracks in your heat exchanger. These byproducts, which may smell like formaldehyde, are a major warning sign.
- Carbon monoxide alarm goes off or you recognize symptoms of poisoning: If a cracked heat exchanger is releasing carbon monoxide into your home, your carbon monoxide alarm may go off or household members may struggle with signs of carbon monoxide poisoning. Complications include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If an alarm goes off or you feel sick, get out of the home as soon as you can and then call for help.
- Soot: If you notice black sooty collecting near the exterior of your furnace, it’s more evidence something may be seriously wrong.
What You Should Do if the Furnace Heat Exchanger is Cracked
If you worry your furnace has a cracked heat exchanger, hire a pro experienced in furnace installation right away so they can inspect your system and, if necessary, handle a furnace heat exchanger replacement. Costs will differ depending on the situation, but estimates can roughly suggest $1,000 to $3,000.
However, the good news is that heat exchangers are generally included in the warranty. It's a good idea to confirm the warranty paperwork on your furnace, since while the warranty won't always 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 most convenient ways to minimize the risk of problems in your furnace overall is via consistent furnace maintenance. Furnaces work the best when they work efficiently. Contacting a skilled professional to check your furnace for old parts, clogs in the air filters and other likely problems can keep you from getting a big bill later on.
It’s also a good idea to review your furnace filters every few months – it’s ideal some filters be swapped out 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 the entire furnace work longer to complete its job. And the harder your furnace works, the more deterioration pieces like the heat exchanger will sustain.