The most efficient dishwasher on the market right now is the Asko D3121XL. Dishwashers that are manufactured today are all "energy efficient." Some have water saving features, others have dry cycle options that save electricity, and still others have even more features. The more features, the most costly the unit, of course. If you're in the market for a new dishwasher, the best thing to do is to visit a store that carries several brands and has knowledgeable sale people who can show you the plus features on each one and help you understand the long-term cost savings.