An apparatus and method for the distillation of ocean and brackish water that includes insulation for preventing heat from escaping to the atmosphere is disclosed. The insulation comprises a second wall surrounding the basic assemblies of a desalination system in which the space between the second wall and basic assemblies is under low partial vacuum and is partially or totally filled with an insulation material for structural support. The system allows for flash evaporation of heated input water and condensing the resultant vapors into pure distilled water. The heat of condensation as well as heat from the salt byproduct may be recaptured and used to preheat the input contaminated water.