A furnace is often a background player at home, ensuring you're warm in the cold winter months. It often won't be noticed until something breaks down.
One source could 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 flows through the system. It typically does this using coils or tubes that heat up the air while acting 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?
Thanks to its important role, it shouldn't come as a surprise that a damaged heat exchanger can be hazardous. Cracks in the heat exchanger can enable dangerous gasses – like carbon monoxide, which can be lethal – to flow across your home.
For this reason, never turn on your furnace if you think you're dealing with a cracked heat exchanger, as letting it run could make the whole household ill. Contact an HVAC professional right away if you think your heater has a cracked heat exchanger that should be repaired.
Four Warning Signs of a Cracked Heat Exchanger:
- Furnace shuts off: Cracks in the heat exchanger could cause your furnace to switch off.
- Strange Smells: If the air leaving your furnace has a strong chemical scent, it might be an indicator that gasses are seeping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a common warning sign.
- Carbon monoxide alarm goes off or you recognize health problems: 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. Side effects include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If an alarm goes off or you feel unwell, leave the home as soon as you can and then call for help.
- Soot: If you see black sooty collecting on the exterior of your furnace, it’s an indication something might be seriously wrong.
What You Should Do if a Furnace Heat Exchanger is Cracked
If you suspect your furnace has a cracked heat exchanger, contact a professional well versed in furnace installation right away so they can examine your system and, if required, perform a furnace heat exchanger replacement. Costs should fluctuate depending on the situation, but estimates often hover around $1,000 to $3,000.
However, the good news is that heat exchangers are often covered by the warranty. It's a good idea to review the warranty paperwork on your furnace, because while the warranty won't always cover the entire cost of repairs, it still may significantly shrink your bill.
How to Prevent a Cracked Heat Exchanger in Your Home
One of the best ways to prevent a problem in your furnace overall is through consistent furnace maintenance. Furnaces offer the most benefits when they work efficiently. Hiring a skilled professional to examine your furnace for broken-down parts, dirty filters and other likely 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 recommended 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 drawing air through a clogged filter makes the entire furnace work more vigorously to accomplish its job. And the harder your furnace has to work, the more strain components like the heat exchanger will endure.