The answer to 'how much to replace heat exchanger' is that the cost to replace a heat exchanger can vary significantly depending on factors like the size and type of HVAC system, the complexity of the repair, and your local labor rates. In general, you can expect to pay anywhere from $1,000 to $3,000 or more to replace a heat exchanger. The higher end of that range is more common for larger, more complex systems.
The heat exchanger is a critical component of your furnace, so it's important to have it replaced by a qualified HVAC technician. They can properly diagnose the issue, source the right replacement part, and ensure the new heat exchanger is installed safely and up to code. Getting multiple local quotes is essential to finding a fair price in your area.