The research aims to develop a compact prototype with low visual impact that is able to take advantage of solar energy to heat water collected from rain. The methodology used involves a study of the art of these systems, which was complemented by a research of related patents. The mathematical concepts governing heat transfer for these types of systems were analyzed and then simulated in Autodesk CFD. We also rely on the TRNSYS simulation software to estimate the temperature values that can reach Zinc roofs under tropical climatic conditions such as Panama. The system was built and tested, obtaining results such as reaching temperatures in the water very close to the surface temperatures of zinc. The decrease in the amount of heat entering the residence was also visualized.Keywords: heat exchanger, Solar Energy, Water Heater, Rainwater harvesting, Zinc Roof