With its growing economy and population, the need of energy for facilities in Indonesia increases, particularly in a hospital. Energy needs for the air conditioning system in the hospital is very large, so that the effort to use energy efficiently becomes very important. The purpose of this study is to investigate the influence of heat pipe heat exchanger (HPHE) applied to the ducting of air conditioning system to effectiveness and energy recovery. This study will also focus on economic analysis to determine the feasibility of HPHE applied in the air conditioning system. The HPHE used in this research is varied in 1, 2, and 3 modules which consists of 12 heat pipes each module are arranged in staggered configuration. Air inlet temperature in the evaporator section is varied of 28, 30, 35, and 40 ° C, and air inlet velocity varied of 1.5, 2.0, 2.5 m/s. Material, production, and installation cost of HPHE in 1, 2, and 3 modules are calculated and compared with electricity energy saving to know how long of time to recover the investment of HPHE. The results show that the maximum effectiveness of 40.25 % obtained at 3 modules of HPHE, with air inlet temperature of 40°C, and the inlet air velocity of 1.5 m/s. It is also found that a maximum heat recovery of 400.54 Watts and annual cost saving of IDR 1.410.205 per year is found when the inlet temperature of 40°C, air velocity of 2.5 m/s, and with three modules installed into the ducting of the air conditioning system. With energy saving of IDR 723,190 per year on air inlet temperature 40 °C and air velocity 2.5 m/s, HPHE with 1 module has a shorter payback period than HPHE with 2 and 3-modules.