The answer to 'heat exchanger repair cost' is that the cost can vary widely depending on several factors. In general, heat exchanger repair costs can range from a few hundred dollars for minor repairs up to several thousand dollars for more extensive work. The exact cost will depend on the type of HVAC system, the extent of the damage, the complexity of the repair, and your location.
Factors that can influence the cost include the age and condition of the heat exchanger, whether it needs to be cleaned or replaced, and the labor rates in your area. Additionally, the cost of any necessary parts or materials will be a factor. It's important to get multiple quotes from local HVAC professionals to get an accurate estimate for your specific situation.