Using an automatic dishwasher is more energy- and water-efficient than washing by hand. And it's even more efficient if you run the dishwasher during non-peak hours, which are usually during late-night hours. But instead of waking up in the middle of the night to turn on the dishwasher, check to see if yours has a "delay" feature. This allows you to fill the dishwasher during the day and automatically start whenever you want, preferably during non-peak hours.