Using solar energy for heating of buildings or Supplying hot water when needed by storing solar energy under ground was investigated experimentally. For this aim, a heating system was built to store solar energy in cylindrical water tank placed under ground via solar collector. In the present study it is obtained that energy saving was seen remarkably in Edirne in Turkey (41 degrees 39 ' 54 '' N) by storing solar energy to use it at other time considering that it would balance difference between consuming and generating energies. During the experimental study, temperature of heat storage unit and surrounding under ground were Measured. In the season of heat storage, efficiency of heat storage unit of cylindrical tank was obtained as 86-96% and it was determined that 89-100%, of total heat was obtained from the sun.