The present invention installed as to prevent relates to a hot water system using the solar energy, only to prevent freezing of the pipe and the heat storage tank of the hot water system, but with the addition heat exchange efficiency falls to enable prevent ingress of corrosion and foreign material of the pipe which is an object to which to reduce costs sikilsu, this object is for each other terminal in communication with a house which is provided with the respective one end is connected to the inlet side and the discharge side of the collector yeolyong inlet pipe and outlet pipe, the home yeolyong inlet pipe and outlet pipe possibly connected as well as a storage tank provided has been receiving incoming pipe and discharge pipe is connected to the hot water the water inflow and outflow, and circulating pumps provided to be installed during the home yeolyong inlet pipe to transmit water stored in the storage tank toward the collector a controller to measure home yeolyong emission observation that is connected to the outlet of the collector and comparing the temperature of the home yeolyong inlet pipe connected to the outlet of the thermal storage tank having a chaon controller is provided for controlling the circulating pump, the home yeolyong incoming When the pipe is installed during charge and discharge of the water freezing temperature, is achieved by including a frost protection means is made in that a drain is provided in order to open and close the filling. Solar, collector, storage tank, freeze, freeze protection valves, hot water system