The high utilization and exploitation of fossil fuel have adverse environmental impacts and efforts to overcome these problems are called for. One of the options is to replace fossil fuel with palm oil which has many similar characteristics with diesel fuel. However, palm oil has a higher viscosity level than diesel oil which may cause imperfect atomization in the nozzle. As a result, a heater is needed to alter the viscosity of the palm oil to be comparable to diesel oil. This research aims to analyze the influence of NaCl concentration in the water heater to the performance of the palm oil heater system. The study was conducted experiments on existing water heater on the Palm Oil Fuel Heater System. NaCl is added to the water heater with a concentration of 2%, 4%, 6%, 8%, and 10%, and be compared with a pure water heater as a reference. From the experiment, known that an increase in NaCl concentration will cause an increase in the boiling point of the water heater, a reduction in heating time, an increase in the output temperature of palm oil. By adding 10% NaCl to the water heater, the heating time will be reduced by 13,6%. However, the addition of this concentration will also cause less optimal heat propagation by conduction from the water heater to palm oil.