A water heater tank has several components formed of a one-piece seamless construction. The water heater tank includes a cylindrical wall with inner and outer surfaces. A helical condenser channel may be formed in the outer surface of the cylindrical wall. The water heater includes a cold water inlet. A cold water channel may be formed in the inner surface of the cylindrical wall in fluid communication with the cold water inlet and the interior volume of the tank.

A modular water heater tank design is provided that enhances the longevity and efficiency of domestic hot water heaters. Interchangeable upper and lower pans allow the water tank to be inverted after several years of continuous use. By repositioning the pans, the thermal stress and temperature gradients experienced by the tank are significantly reduced, thereby extending its operational life. Additionally, the salt precipitation within the tank is removed from new lower pan, ensuring improved heat absorption and preventing premature corrosion.