With the increasing demand of energy saving and emission reduction, low temperature economizer (LPE) is more and more utilized in the heat recovery plant of the coal-fired power plant and because of the obvious advantages in material properties the use of fluorine plastics low temperature economizer has gradually become extensive. In this paper the equivalent heat drop method is utilized to calculate the improvement on net work output as well as the decrease on standard coal consumption rate of the coal-fired power plant system which adds the fluorine plastic economizer. The calculation results indicate that the improvement and decrease are different when the low temperature economizer locates different position of the system and under the same situation, the more stage extraction should be utilized as far as possible to achieve better energy saving effect. In addition the economic and environmental advantages of fluorine plastic economizer are compared with those of the metal economizer. On the economic benefit, the fluorine plastic economizer is significantly greater than the metal economizer and at the same time the carbon emission reductions of fluorine plastic economizer are significantly greater than those of metal economizer. (C) 2017 Elsevier Ltd. All rights reserved.