To reduce the energy consumption in air-conditioning systems without changing the required temperature level in the air-conditioned space, Heat Pipe Heat Exchanger (HPHE) has been experimentally used and tested. The heat pipe has been filled with working fluid by about 50% of the volume of the evaporator which represents the filling ratio. In this research, three mass concentration of nanoparticle from copper oxide (CuO), 1wt%, 3wt% and 5wt% have been used and studied. Additionally, its effect on the HPHE effectiveness and the heat recovery ratio at different inlet air temperatures, 30, 35, 40, 45, 50, and 55 °C, have been determined in the evaporator. The study revealed that the temperature change of the evaporator and condenser has been increased with increasing the mass concentration of CuO and inlet air temperature which passing through HPHE. Furthermore, the results have been illustrated that the increasing of the inlet air temperature and CuO mass concentration leads to an increase in the effectiveness of the heat pipe. The highest level of effectiveness and maximum heat recovery value, at inlet air temperature 55 °C with inlet air velocity 1m/s have been found equal to 0.59346 and 883.284 Watt, respectively.