It is an indirect solar water heater made up of a plane collector of 1.7m2 and a storage tank of 150 liter with a coat exchanger (dual envelope). The operating principle of this type of solar water heater is illustrated by the diagram on figure 1. This product was developed within the framework of a national project of launching of the industry of solar water heater . For this purpose, the equipment is designed for a reproduction in a mass production line. The product was carried out in partnership with several Algerian industrialists to guarantee a high integration rate .