In recent years solar energy has been strongly promoted as a viable energy source. One of the simplest and most direct applications of this energy is the conversion of solar radiation into heat. Solar energy is recognized as one of the most promising alternative energy options. On sunny days, solar energy systems generally collect more energy than necessary for direct use. Therefore, the design and development of solar energy storage systems, is of vital importance and nowadays one of the greatest efforts in solar research. These systems, being part of a complete solar installation, provide an optimum tuning between heat demand and heat supply. Hence way that the domestic sector can lessen its impact on the environment is by the installation of solar flat plate collectors for heating water.