The evaporation is then trapped and cooled. Distilled water is basically condensation. Because the water is boiled and then cooled, the water seems to taste somewhat flat. Keep in mind that distillers require maintenance, much like a coffee maker or humidifier. The minerals build up on the heating element and need to be de-scaled.
Distillers work with electricity and do build up heat.
Reverse Osmosis is a method of filtration by which the water is first mechanically filtered and then the water is pressed through a semi-osmotic membrane. Then the water is passed through a carbon block filter. The reverse osmosis process is slow and therefore requires a holding reservoir of some type. The reverse osmosis process produces waste water. There are 2 important things that effect the performance and lifetime of the unit.