Abstract: The temperature and heat-flow fieldsin a typical water-heating room (5 m × 4 m × 3 m) were mathematically modeled, theoretically analyzed, numerically simulated in finite element method with software Fluent and experimentally evaluated to improve the heat dissipation efficiency.The impact of the heatsink fin configurationand inlet-water temperature on the time evolution of the indoor temperature gradient distribution was investigated.The simulated results show that the inlet-water temperature and fin-blade number strongly affect the temperature gradient distribution.Tobe specific, a higher inlet-water temperature heats up the room to a higher temperature profile with a larger gradient; and more fin-blades heat up the room faster to a steady temperature distribution because of larger heat radiation area.When it comes to fuel saving and comfortable living temperature (22~24℃), we suggest that the inlet water temperature and fin-blade number be 70℃ and 20, respectively.