The answer to 'how much to replace heat exchanger' is that the cost can vary significantly depending on several factors. In general, replacing a heat exchanger in an HVAC system typically ranges from $1,000 to $3,000, but the exact price can be higher or lower based on your specific situation.
The main factors that influence the cost include the size and type of your HVAC system, the accessibility of the heat exchanger, the labor rates in your local area, and whether any additional repairs or replacements are needed. It's important to get quotes from multiple HVAC contractors in your area to get the best price.