Dishwashers and Energy Efficiency

Did You Know? ENERGY STAR qualified models are, on average, 10% more energy efficient than non-qualified models.

ENERGY STAR qualified dishwashers use advanced technology to get your dishes clean while using less water and energy.

  • Trim your utility bills – Do you have a dishwasher made before 1994? If so, you’re paying an extra $40 a year on your utility bills compared to owning a new ENERGY STAR qualified model. Replace one of these old dishwashers with ENERGY STAR and save enough money to pay for dishwasher detergent all year.
  • Save loads of water – A dishwasher built before 1994 wastes more than 10 gallons of water per cycle compared to owning a new ENERGY STAR qualified model. Replace one of these old dishwashers with ENERGY STAR and save enough water each week to wash 3 loads of laundry in an ENERGY STAR qualified clothes washer.
  • Save the environment – Nearly 70 percent of U.S. electricity is generated by burning coal and natural gas, which releases greenhouse gasses and other air pollutants into the atmosphere, contributing to climate change and air quality problems. ENERGY STAR qualified dishwashers use less energy than conventional models, which helps reduce air pollution and combat global climate change. By reducing water consumption, ENERGY STAR qualified dishwashers also help protect our lakes, streams, and oceans.

Federal agencies are required by the Energy Policy Act of 2005 (P.L. 109-58) and Federal Acquisition Regulations (FAR) Subpart 23.2 to specify and buy ENERGY STAR®-qualified products or, in categories with no ENERGY STAR label, FEMP-designated products which are among the highest 25 percent of equivalent products for energy efficiency.

Performance Requirements for Federal Purchases
Dishwasher Type Energy Factora Annual Energy Useb
Standard 0.65 or greater 339 kWh or less
Compact 0.88 or greater 252 kWh or less

a Energy Factor is the inverse of the power consumption (in kWh) for one full wash cycle.
b Based on annual standby energy use plus the active energy use from 215 wash cycles, where one cycle is one normal operation with a fully loaded machine.

Buying Energy-Efficient Residential Dishwashers

When buying residential dishwashers directly from commercial sources, select products that are ENERGY STAR-qualified  and also do not exceed the annual energy use shown in the Performance Requirements table. Most manufacturers display the ENERGY STAR label on complying models. For dishwashers that do not display the ENERGY STAR, check the annual energy use listed on the yellow EnergyGuide label for products that meet this Specification.

Performance requirements apply to all forms of procurements, including: guide and project specifications; construction, renovation, repair, maintenance and energy service contracts, lease agreements and solicitations for offers. Energy performance requirements should be included in all evaluations of solicitation responses.

The federal supply sources for residential dishwashers are the General Services Administration (GSA) and Defense Logistics Agency (DLA). GSA sells dishwashers through its Multiple Awards Schedules program and on-line shopping network, GSA Advantage! DLA offers them through the Defense Supply Center Philadelphia and online through DoD EMall. Note that not all dishwashers sold by GSA and DLA are ENERGY STAR-qualified and some products that do qualify may not be indicated as such. When buying dishwashers through these sources, check the models you are considering against the list of qualified products on the ENERGY STAR web site to assure that they meet this Specification.

Agencies can claim an exception to these requirements through a written finding that no ENERGY STAR-qualified or FEMP-designated product is available to meet the functional requirements, or that no such product is life-cycle cost-effective for the specific application.

Low Standby Power

Federal agencies are required to purchase products that use one watt of power or less while in standby mode. Features such as soft touch controls and digital displays use power even when the dishwashers are not working. For some products, FEMP sets a separate standby level. However, since the measurement of annual energy use includes both standby and wash-cycle energy, FEMP requires that in addition to being ENERGY STAR-qualified dishwashers have a maximum annual energy use of 380 kWh for standard models and 288 kWh for compact models.

User Tips

Dishwashers require the hottest water of all household uses, typically 135 to 140°F. However, these products are usually equipped with booster heaters to raise incoming water temperature by 15 to 20°F. Setting the water heater between 120 and 125°F and turning the dishwasher’s booster on will provide sufficiently hot water while saving energy and also reducing the chances for scalding.

Cost-Effectiveness Example
Performance Base Modela Required Best Available
Energy Factor (EF) 0.46 0.65 1.11
Annual Energy Use 493 kWh 339 kWh 194 kWh
With Electric Water Heating
Annual Energy Cost $30 $20 $12
Lifetime Energy Costc $280 $190 $110
Lifetime Energy Cost Savings $90 $170
With Gas Water Heating
Annual Energy Cost $20 $14 $8
Lifetime Energy Costc $190 $120 $65
Lifetime Energy Cost Savings $70 $125

a The efficiency (EF) of the Base Model is the minimum allowed by US DOE appliance standards.
b More efficient products may have been introduced to the market since this specification was published. Information on the Best Available model was obtained from the ENERGY STAR dishwasher products list.
c Lifetime Energy Cost is the sum of the discounted value of annual energy costs based on average usage and an assumed dishwasher life of 13 years. Future energy price trends and a discount rate of 3.0% are based on federal guidelines (effective from April 2006 to March 2007).

Cost-Effectiveness Assumptions

In the example above, the Base Model is a standard dishwasher with an EF of 0.46 and a standby power of 3 watts. The Required model has an EF of 0.65 and standby power of 1 watt while the Best Available has an EF of 1.11 and uses no standby power. Annual energy use in this example is based on the standard DOE test procedure. The assumed prices for electricity and natural gas are 6¢ per kWh and 60¢ per therm, the average at federal facilities in the US.

Using the Cost-Effectiveness Table

With electric water heating, the Required model is cost-effective if its purchase price is not more than $90 above that of the Base Model. The Best Available dishwasher is cost-effective if its price is no more than $170 above the Base Model.

If using gas water heating, the Required model is cost-effective if its purchase price is no more than $70 above the price of the Base Model. The Best Available dishwasher is cost-effective if its purchase price is no more than $125 above the price of the Base Model.

What if my Utility Prices are Different?

ENERGY STAR has an EXCEL-based cost calculator for dishwashers on its Web site, click on Savings Calculator – Dishwashers. Select the water heater type and input the rates for electricity, natural gas and water at your facility. The output section will automatically display results that more accurately reflect your utility costs.

www1.eere.energy.gov

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