The disclosure provides systems methods and apparatus for purifying water. A purification device includes a heating vessel adapted to receive impure water and output water or water vapor. The device further includes at least one heating element arranged outside and in thermal contact with the heating vessel, configured to provide heat to the impure water. The device also includes at least one heat exchanger to exchange heat between the impure water and the water vapor to raise the temperature of the impure water. In some example implementations, the at least one heating element can include a Peltier cell.