Abstract: The present invention describes enhancement of non-solar water heating systems (such as systems that operate on gas, diesel fuel, or electricity energy) to work with solar heating panel as well. The retrofitable system addresses the need to provide a simple to install, cheap, and clean add-on solar panel and parts to existing non-solar based heating systems. The hot water extracted from the system has homogeneous temperature, and when water is not taken from the system the hot water are being collected in the existing boiler.