Space heating and cooling appliances consume a significant amount of energy in buildings. In recent decades, ground source heat pump (GSHP) systems have become popular for space heating applications in many countries. However, countries like India need both space heating and cooling and hence its performance needs to be evaluated in both heating and cooling functions for economical operation. The experimental results obtained for both modes of operation are discussed in detail in this paper. Details of the experimental setup used, measurements, performance of ground heat exchanger (GHX) used and calculation of COP, effectiveness and extraction/injection are explained. Using the experimental data the coefficient of performance (COP) of heat pump and GSHP are obtained. The average COP of the GSHP system obtained during space cooling was found to be 21% less than the value obtained for heating mode operation and also heat extraction by the GHX fluid is observed to be high at the starting of the operation. In heat injection mode, as the operational time increases, the surrounding soil temperature also increased thus creating more resistance for heat flow. The average effectiveness of GHX was found to be 0.29 and 0.33 in heating and cooling mode operations respectively. (C) 2016 Elsevier B.V. All rights reserved.