In this paper, an exergy analysis is performed for a double slope solar still equipped by thermoelectric heating modules to achieve a better thermodynamic performance. Thermoelectric modules were used as a water heater to increase the temperature of water and accordingly improve the performance of the solar still. The results are obtained by performing a series of experiments during ten days and nights under the climate conditions of Semnan (35 degrees 33' N, 53 degrees 23' E), Iran. Finally, an economic analysis has been performed to determine the production cost of water per liter. The obtained results showed that the heatsink temperature and heating created by thermoelectric cause an increase in the water temperature. This prevents reduction in production when the solar intensity decreases at afternoon. Moreover, it is observed that the exergy efficiency increases during the times of experiments. The maximum exergy efficiency of the system is about 25% and occurred at 3 p.m. Life cycle analysis also showed that the cost of distilled water for the day and night are 0.1422 and 0.237 $/L/m(2), respectively.