The Bonn study proves that the dishwasher uses only half the energy and one-sixth of the water, less soap too. Even the most sparing and careful washers could not beat the modern dishwasher. The study also rated the cleanliness achieved, again in favor of the washing machine (sorry grandma). There have been studies before, but this is one of the few that stands (wo)man against machine and it sets itself apart by including a thorough analysis of the effect of half-loads and the whole demand range from your cake plate to the grimiest pots. Surf to research under household technology at U. Bonn's site for more. :: U. Bonn Household Technology