We aimed to compare underwater plasma discharge type boiler (Group 1) and conventional electric boiler (Group 2) for the heating energy saving in greenhouses. Two type boilers were installed in Zamioculcas zamiifolia growing greenhouse. As a result, the temperature differences from the set temperature were 2.1℃, 2.5℃ for Group 1 and Group 2. The water temperature difference of Group 1 was about 23~47℃ lower than Group 2, and the water temperature in Group 1 rose faster to the set temperature. The heating energy supplied to greenhouse tended to be high in Group 2, and there was no significant difference in the amount of heat loss according to heating methods. In addition, growth characteristics of Zamioculcas zamiifolia were investigated according to the heating methods, and leaf length, leaf width, tree height, and NDVI (Normalized difference vegetation index) were measured. As a result, it was confirmed that there is no significant difference according to the heating methods. Thus, we considered that the underwater plasma discharge type boiler can be used to heat greenhouse. The energy consumption were 5,051 kWh, 6,073 kWh for Group 1 and Group 2, so it was found that the underwater plasma discharge type boiler had about 17% heating cost saving effect.