The vacuum tubes trap incident sun rays, and convert it to heat inside the inner tube. Water, now being heated its temperature rises, density changes, and hot water sections rise through the tube to the top of the tank, while cold water from the bottom of tank replaces it in the tube, to start the cycle again. This natural cycling of water driven by temperature difference keeps water hot when stored in an insulated tank.

The Solar Water heater tank is a non-pressurized tank, and has an opening to the ambient atmosphere. Solar water heater tank should always be filled with water to avoid damage caused by dry high temperature working conditions. The stainless steel our use belong to food grade, and SUS 304 & SUS 316 have better corrosion resistance.