Dishwasher energy and water use would continue to decline with new efficiency standards

Posted on December 11, 2014 by
Joanna Mauer

The U.S. Department of Energy (DOE) proposed strong new efficiency standards today for dishwashers that would reduce energy and water use by 24% and 38%, respectively. The new standards would save money for consumers on their utility bills and help continue the 25-year trend of declining dishwasher energy and water use.

DOE estimates that the new standards would save 1 quadrillion Btus of energy over 30 years of sales, an amount equivalent to the annual energy use of almost six million U.S. households, and save 240 billion gallons of water, which is equivalent to almost two years of water consumption of all the residents of Los Angeles. The new standards would also net consumers up to $2 billion in savings.

The current dishwasher standards which took effect in 2013 specify a maximum energy use of 307 kilowatt-hours (kWh) per year and a maximum water use of 5 gallons per cycle. The proposed standards would lower these energy and water use thresholds to 234 kWh per year and 3.1 gallons per cycle, respectively. Compared to a dishwasher that just met the 2010 standards, a dishwasher meeting the new proposed standards would consume one-third less energy and only half as much water.

Dishwasher savings graph

There are dishwashers on the market today from multiple brands that already meet the proposed standards.

The energy and water use of dishwashers have decreased dramatically over the last 25 years, while prices have also come down. In our 2013 report, Better Appliances, we found that since 1987, the average energy use of dishwashers has decreased by about 50% while real prices decreased by 30%. And while typical dishwashers 25 years ago consumed more than 10 gallons of water per cycle, new dishwashers that just meet the current standards consume half that amount.

As the energy and water use of dishwashers have declined, manufacturers have maintained washing performance. In 2012, 92% of all dishwashers rated by Consumer Reports were rated as having “very good” or “excellent” washing performance. And in Consumer Reports’ latest ratings of dishwashers, more than 75 dishwashers are rated as “excellent” on both washing performance and energy use. In testing conducted to prepare today’s proposed rule, DOE found that products that meet the new proposed standards can maintain cleaning performance without increasing cycle time.

DOE is scheduled to publish a final rule by October 2015, and the new standards would take effect in 2019.