Single Event Upsets (SEUs) inadvertently change the logic memory and thereby the configuration of the Field Programmable Gate Arrays (FPGAs), leading to their incorrect functioning. Traditional methods to tolerate such faults include Triple Modular Redundancy (TMR). However, such method has a high overhead in terms of power and area. Moreover, the inexact methods used in ASICs to overcome this problem are not efficient when applied in FPGAs. Therefore, this paper proposes a novel technique based on heuristic to tolerate faults in SRAM-based FPGAs by using inexact modules in conjunction with TMR, thus reducing the area and power overhead of the design. Experiments run on various MCNC benchmark circuits show the accuracy of the proposed technique. They also show that the design solutions found through this technique only differ 0.52% on average from the optimal ones and savings up to 84.4% in terms of computation time can be reached on average.