Abstract: A solar water heating system comprises a solar collector having coils consisting of several stages, some of the coils having transparent covers having different heat insulation effects increasing with the temperature in the coil stages. Water is introduced to the collector either from a cold water source or from the hot water storage tank. The hot water discharge from the collector is divided into two branches, one branch leading to a mixing valve and one to a storage tank. Discharge from the storage tank leads either to the hot water line to the consumer or to an excess water utilization means, such as a spray to wash the collector, to an irrigation system, a roof cooling system or the like. The present invention improves the efficiency of the system and increases the accumulative capacity of the tank. Existing tank heaters may be used to reduce cost.