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Dishwashing

This is a consumer page on dishwashing. For more resources related to dishwashing, visit the dishwashing topic page.

About 60% of the energy used by a dishwasher goes towards heating the water, so models that use less water also use less energy. Thanks to national efficiency standards, new models use a fraction of the water and energy of older models. New standards limit water use to 6.5 gallons per cycle; the best models use as little as 1.5 gallons per cycle. Even as dishwashers have become more miserly in their water use, they have made great strides in cleaning performance.

Part 1: Buying a New Dishwasher
Part 2: Energy Saving Tips

 

Buying a New Dishwasher

 

To find the most efficient products, download a list of qualifying products from the ENERGY STAR Web site (link to excel file in the upper-right). Sort by "Size" and "Energy Factor" to see which meet our recommendations (below). You may need to also check product literature or with your utility for further specifications. For a quick search by manufacturer, here's a direct link to the list in html. To identify the most efficient products, their prices, and where to buy locally, see the Top Ten USA listings.

When buying a new dishwasher, consider the following:

1. Low Energy Use 
ACEEE recommends that you consider dishwashers have an estimated energy use of less than 295 kWh/year. This is about 40% better than the federal standard. You can find which products meet this requirement on the showroom floor by looking on the yellow EnergyGuide label on each product.

2. Low Water Use
To find the most water-efficient models, you must look beyond ENERGY STAR and EnergyGuide. Some ENERGY STAR models use half as much water as others, saving hundreds of gallons of water each year. Check the manufacturer’s literature or contact your local water utility. In some states, electric and water utilities offer rebates for the purchase of models that are exceptionally efficient.

3. Wash Cycle Options
Most dishwashers have several different wash cycle selections. The more options you have, the better you can tailor the energy and water use needed for a particular load. Look at the manufacturer’s literature for total water use with different cycles.

Some dishwashers on the market today use “soil sensor” technology to automatically adjust water use depending on how dirty the dishes are in each load. There are highly-efficient dishwashers with and without this feature.

4. Energy-Saving “No-Heat” Dry
An electric heating element is generally used to dry dishes at the end of the final rinse cycle, consuming about 7% of dishwasher energy use. Most new dishwashers offer an energy-saving no-heat drying feature. At the end of the rinse cycle, if the feature is selected, room air is circulated through the dishwasher by fans, rather than using an electric heating element to bake the dishes dry.

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Energy Saving Tips

 

Whether you are buying a new dishwasher or using an existing one, you may be able to save a considerable amount of energy by changing the way you operate it.

  • Avoid Hand-Washing
    Studies are showing more and more that, when used to maximize energy-saving features, modern dishwashers can outperform all but the most frugal hand washers.
  • Scrape, Don’t Rinse
    Studies show that most people pre-rinse dishes before loading them into the dishwasher, even though dishwashers purchased within the last 10 years do a superb job of cleaning even heavily soiled dishes. If you find you must rinse dishes first, get in the habit of using cold water.
  • Follow Manufacturer Instructions
    Completely fill the racks to optimize water and energy use, but allow proper water circulation for adequate cleaning.
  • Wash Only Full Loads
    The dishwasher uses the same amount of water whether it’s half-full or completely full, so nothing will save more energy than waiting to run your dishwasher. If you find that it takes a day or two to get a full load, use the rinse and hold feature common on newer models. This will prevent build up of dried-on food while saving time and water compared to pre-rinsing each item. The rinse feature typically uses only 1 to 2 gallons of water.
  • Use Energy-Saving Cycle Options
    Pay attention to the cycle options on your dishwasher and select the cycle that requires the least amount of energy for the job. Use the no-heat air-dry feature on your dishwasher if it has one.
  • Turn Down the Water Heater Temperature
    Since the early 1990s, most dishwashers in the U.S. have been sold with built-in heaters to boost water temperature to 140–145°F, the temperature recommended by manufacturers for optimum dishwashing performance. The advantage to the booster heater is that you can turn down your water heater thermostat to 120°F (typically half-way between the “medium” and “low” settings).

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Page last updated December 2012