With a range of options for Energy Star-rated appliances, recycled content, and low-VOC finishes, the kitchen is one of the easiest places to go green. And you can bet it's the most noticeable. One place to start is with one of the most visible energy hogs in the room: Cycle by cycle, the dishwasher motors away to heat, spray, and drain the water necessary to remove those baked-on, caked-on, stuck-on foods.

To its credit, the average dishwasher is much more water friendly than traditional hand washing. Using any Energy Star-qualified dishwasher instead of hand washing saves 5,000 gallons of water, $40 in utility costs, and 230 hours of labor annually. Still, manufacturers report that even the greenest dishwashers on the market must continue to find a balance of energy efficiency, water conservation, sound emission, and basic performance.

"That is exactly the difficult trade-off that we have to strike on all of our projects," says Paolo Falcioni, international technical affairs manager for Indesit, an Italian company launching its line of Hotpoint Ariston dishwashers in the U.S. this year. "It is easy to use less water and less energy, but without having clean dishes at the end; the task at hand is to clean dishes, and that needs to be done perfectly. That's why someone is ready to buy a dishwasher to begin with."

Pure Energy

In Europe, Falcioni and his peers rely on the EN50242 standard, which measures washing and drying efficiencies but also sets base standards for energy and water conservation and noise emissions reduction. The stateside equivalent is Energy Star; qualifying dishwashers consume 40% less than the federal standard. Although the Energy Star program does not include a metric for water consumption, qualified dishwashers typically use one-third less water than nonqualified models.

A metric called the Energy Factor--the reciprocal of the sum of a machine's electrical energy per cycle plus the water heater energy consumption per cycle expressed in cycles per kWh--determines energy consumption. As of Jan. 1, 2007, the federal minimum Energy Factor for dishwashers is 0.46, thus a machine must achieve an Energy Factor of 0.65 to qualify for the Energy Star label.

Ever since Energy Star began certifying dishwashers in October 1996, manufacturers have been quick to adjust performance metrics to meet program standards. The amount of hot water a dishwasher uses largely establishes its energy efficiency. Older dishwashers sprayed large amounts of hot water on dishes in a short period of time, while contemporary models use finer, more targeted streams.

Currently, 695 dishwasher models across 52 brands qualify for the Energy Star label. In fact, dishwasher manufacturers are getting so efficient that the government is raising the thresholds for both the minimum federal standard and the Energy Star program. As part of that process, a metric for water consumption likely will factor into qualification requirements for the first time.