If you want to save electricity and water, you have to use maximize the use of your washer. Wash in full loads, lessen laundry usage, use cold water or set the water level to just under what you have been using previously.

http://www.washingmachineadvisor.com

Here’s the actual study: http://www.landtechnik.uni-bonn.de/ifl_research/ht_34/Report_Dishwasher_RRT2009_1.pdf

And a follow up on the differences produced by individuals: http://www.treehugger.com/files/2009/01/built-in-dishwasher-vs-hand-washing-which-greener.php

It probably doesn’t take into account that you use indeed more dishes if you have a dishwasher and more clothes if you have a washing machine

I am suprised to hear that dishwashers use less energy than hand washing. I wash all my dishes by hand (mainly because I am too cheap to buy a dishwasher and there is no place in my kitchen to put one). I figure that I use about 5 gallons of water per day to do this, all of which is heated in my hot water tank. However, I think the actual number of hot gallons I use would be closer to 3, since the uncut water coming from my tank is too hot for my hands. In essence, this boils down (no pun intended) to whether heating 3 gallons of water (and storing it) consumes more energy than a dishwasher uses in a typical run, assuming that one runs the dishwasher every day. I’m a bit skeptical, but willing to be convinced. Do you have a reference I could look up?