Will a cracked heat exchanger symptoms?
Your furnace might stop working if you’re lucky, but most often, it will keep running even with a crack, allowing carbon monoxide to seep into your house. The only signs that you have a damaged heat exchanger is either no heat during the winter, reoccurring flu-like symptoms, or a beeping carbon monoxide detector.
How long will a cracked heat exchanger last?
Rust tends to eat away any metal and could cause a crack on the heat exchanger. If you’ve poorly maintained your system, rust can build on the components and develop cracks. The average lifespan of a furnace’s heat exchanger is 15 years.
What to do if you have a cracked heat exchanger?

If you have a crack in your heat exchanger, you only have two good options: replace the heat exchanger or replace the furnace. There’s no safe way to truly repair a heat exchanger.
How do you fix a crack in a heat exchanger?
The best way to repair a cracked heat exchanger is to remove it and put in a new one. This doesn’t require replacing other parts of the furnace. However, it’s an expensive repair. Often a repair that’s too expensive compared to having a new furnace put in.
Can you repair a cracked heat exchanger?
Unfortunately, heat exchangers cannot be repaired. When a heat exchanger cracks or rusts through it must be replaced. Because the heat exchanger is at the center of the furnace, nearly the whole furnace must be disassembled. Even if the parts are covered under warranty, the labor and freight will start around $500.

How common is a cracked heat exchanger?
We give free second opinions on cracked heat exchangers. In a typical season, our NATE certified furnace technicians confirm less than 10% of these as real cracks. The other half turn out to be unethical tactics to sell new furnaces.
What causes cracks in heat exchanger?
Heat exchangers are made of metal that expands and contracts every time your furnace turns on and off. Over time, this stress creates cracks in your heat exchanger. If you keep your furnace well maintained throughout its lifetime, you can significantly prolong the amount of time it takes for those cracks to develop.