The thermodynamic (energy and exergy) analysis of a condensate heating system, its segments, and components from a marine steam propulsion plant with steam reheating is performed in this paper. It is found that energy analysis of any condensate heating system should be avoided because it is highly influenced by the measuring equipment accuracy and precision. All the compo-nents from the observed marine condensate heating system have energy destructions lower than 3 kW, while the energy efficiencies of this system are higher than 99％. The exergy efficiency of closed condensate heaters continuously increases from the lowest to the highest steam pressures (from 70.10％to 92.29％). The ambient temperature variation between 5 ℃ and 45 ℃ notably influences the exergy efficiency change of both low pressure heaters and the low pressure segment equal to 31.61％, 12.37％, and 18.35％, respectively.