A dishwasher with a good range of programs, including economy options, will allow you match the dishwasher's performance to your needs and help you save energy and water. Most of the energy used by a dishwasher is for water heating. The Energy Guide label estimates how much power is needed per year to run the appliance and to heat the water based on the yearly cost of gas and electric water heating. When it is time to buy a new unit, look for the ENERGY STAR label.
Appliances account for about 20% of your household's energy consumption, with refrigerators and clothes dryers at the top of the consumption list. Check the manual that came with your dishwasher for the manufacturer's recommendations on water temperature; many have internal heating elements that allow you to set the water heater to a lower temperature.