Abstract: A heat exchanger assembly includes at least first and second coils adapted to contain a fluid therein and at least two support members securing the coils. Each of the first and second coils are individually formed of at least one tube including an inlet at an uppermost extent thereof and an outlet at a lowermost extent thereof and include a vertical column containing a plurality of horizontal rows and a plurality of bends at opposite ends of the horizontal rows and fluidically interconnecting the horizontal rows thereof in series to define a serpentine configuration. The first and second coils are adjacent each other and nested so that the horizontal rows of the first coil are parallel to the horizontal rows of the second coil and at least some of the horizontal rows of the first coil are disposed between adjacent pairs of the horizontal rows of the second coil.