The job of a heat exchanger is to capture heat from burning gas and transfer it to your pool’s water—the more efficiently, the better. The combination of operating heat and pool water chemistry is very tough on exchangers, leading to corrosion and failure. That’s why we made the ETi 400 High-Efficiency Heater’s direct-fire heat exchanger from pure titanium. It provides a long life even under extreme conditions and is the most corrosion-resistant material in the industry. The ETi heater has the highest efficiency in its class and is the longest lasting heat exchanger ever built, with ASME-certified construction.