Abstract: A solar heat exchanger comprising a frame having an inner surface area defined by upstanding walls, ends and bottom wherein an insulation layer of relatively uniform thickness is spread throughout the inner surface. A plurality of channels are spaced throughout the frame. The channels may be arranged in a serpentine or manifold design and may comprise an outer curved wall and an inner curved wall wherein water flows through the inner and outer curved wall and spaced between the inner and outer curved wall in a restricted manner. Additionally, the frame may include a top insulation layer comprising generally parallel panels spanning the frame and creating a greenhouse effect upon the channels. Inlet and outlet means are provided within the frame to allow cooler water to enter the exchanger and warmer water to exit.