⎯cruise ship is a ship used for recreational and entertainment purposes. As a means of vacation and entertainment, the design of this transportation requires more attention. The design of the ship itself must be able to make it comfortable for the passengers. One of them, to increase comfort for cruise ship passengers is by adding heating water to the domestic system. Will need a large amount of electrical energy if using an electric heater. While in the engine room there is exhaust heat that can be utilized. The purpose of this research is to plan the utilization of waste heat contained in the exhaust gas and cooling water system (high temperature) as a water heater on the domestic system. The method used is the analysis of calculations. From the results of the calculation analysis, it was found that the hot water requirements of this ship were 3409 liters/day and needed a heat 167.12 kJ/s to increase the water temperature from 25 o C to 66 o C. From the calculation results, the 50% load engine has a heat 469 kJ/s, 75% load engine has a heat 645 kJ/s, 80% load engine has a heat 729 kJ/s, 100% load engine has a heat 781 kJ/s, while in cooling water system (high temperature) has a heat 252 kJ/s. Tank insulation using glass wool with a thickness of 610 mm. While the insulation on the pipe uses glass wool with thickness 50 mm. By replacing the electric water heater by utilizing heat waste can minimize the cost up to Rp.245,211.833/day or Rp.7,356,355.008/month.