A furnace is usually a background player for your home, ensuring you're warm during the cold winter months. It frequently doesn’t get noticed until something goes wrong.
One cause could be that your furnace has a cracked heat exchanger. It can potentially be hazardous, so it’s worthwhile to learn the symptoms of a cracked heat exchanger and what to do if you believe that may 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 through the system. It typically handles this using coils or tubes that heat up the air while acting as a barrier to keep gas created in the combustion chamber, called flue gasses, from leaking out into your home.
Is a Cracked Heat Exchanger Dangerous?
Because of its important role, it’s no surprise that a damaged heat exchanger can be hazardous. Cracks in the heat exchanger can allow dangerous gasses – like carbon monoxide, which can be lethal – to circulate through your home.
For this reason, don't ever turn on your furnace if you believe it has a cracked heat exchanger, as doing so could make the entire household ill. Call an HVAC professional immediately if you are worried your heating has a cracked heat exchanger that needs repair.
Four Signs of a Cracked Heat Exchanger:
- Furnace shuts off: Cracks in the heat exchanger can cause your furnace to turn off.
- Odd Smells: If the air coming out of your furnace has a powerful chemical scent, it could be an indicator that gas is seeping through cracks in your heat exchanger. These byproducts, which can smell like formaldehyde, are a common warning sign.
- Carbon monoxide alarm is triggered or you recognize symptoms of poisoning: If a cracked heat exchanger is relieving carbon monoxide inside your home, your carbon monoxide alarm should go off or household members may start experiencing signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling drowsy. If the alarm goes off or you feel unusually tired, exit the home immediately and then call for help.
- Soot: If you see black sooty collecting on the exterior of your furnace, it’s an indication something could be seriously wrong.
What You Can Do if a Furnace Heat Exchanger is Cracked
If you suspect your furnace has a cracked heat exchanger, call a professional with extensive experience in furnace installation as soon as possible so they can inspect your system and, if needed, perform a furnace heat exchanger replacement. Costs often fluctuate depending on the situation, but estimates can roughly suggest $1,000 to $3,000.
However, the good news is that heat exchangers are often included in the warranty. You should check the warranty paperwork on your furnace, since while the warranty won't always cover the entire cost of repairs, it could significantly lower your bill.
How to Avoid a Cracked Heat Exchanger in Your Home
One of the best ways to minimize the risk of problems in your furnace overall is via regular furnace maintenance. Furnaces work the best when they work efficiently. Calling a trained professional to check your furnace for old parts, clogged filters and other common problems can keep you from getting a big bill later on.
It’s also a good idea 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 aren't a part of the heat exchanger itself, the strain of drawing air through a clogged filter makes the entire furnace work harder to complete its job. And the harder your furnace needs to run, the more wear and tear pieces like the heat exchanger will sustain.