The answer to 'how often to replace heat exchanger' is that the heat exchanger in a furnace or boiler should typically be replaced every 10-15 years, or whenever it shows signs of significant wear or damage. The heat exchanger is a critical component that transfers heat from the combustion process to the air or water circulating through the HVAC system. Over time, the metal can become cracked or corroded, reducing efficiency and potentially leaking dangerous combustion gases.
It's important to have a professional HVAC technician inspect the heat exchanger annually during a routine maintenance visit. They can identify any issues and recommend whether replacement is necessary. Replacing the heat exchanger proactively before it fails can help extend the life of the HVAC system and ensure safe, efficient operation.