Dishwashers
The US Department
of Energy's Energy Star Program has measured
energy efficiency for washing machines and other major appliances, TVs,
VCRs, heating and cooling equipment, residential light fixtures, office
equipment, windows, and newly built homes. These products were tested
for energy efficiency and operational cost factors. See www.energystar.gov/products for Energy Star products, retail stores selling them, and other related
information.
Most of the energy
used by a dishwasher goes toward heating the water which accounts for
approximately 80% of the total energy used. Models that use less water
use less energy. There are also several other factors that affect the
energy use of dishwashers:
- Booster Heater:
Some dishwashers automatically boost water temperature, while others
use built-in heaters to boost water temperature. Each 10 degree reduction
in the water heater temperature setting cuts energy consumption from
water heating by 3-5%. Make sure that you check the dishwasher manufacturer's
instructions for the minimum recommended water heater temperature setting
(usually 120 degrees).
- Energy-Saving
Wash Cycles: Most dishwashers today have several different wash
cycle selections. If your dishes are only slightly soiled, you can use
a "light wash" cycle and save energy by using less water and
operating for a shorter period of time.
- Energy-Saving
"No Heat" Drying: Generally, an electric heating element
is used to dry dishes at the end of the final rinse cycle. Some new
dishwashers offer an energy-saving no-heat drying feature. If you choose
to use this feature, room air is circulated through the dishwasher by
fans, rather than using an electric heating element to dry the dishes.
Buying a New
Dishwasher
- The rating that
you will find on the EnergyGuide label is based on 322 cycles annually
on the normal setting. If you plan to buy a model that features other
settings that you might use more often, your energy use could vary substantially.
- There are two
dishwasher classifications: compact capacity and standard capacity.
Compact models will use less energy, but they will also hold fewer dishes.
If you have to use the dishwasher more frequently, you may use more
energy.
- Realize that the
manufacturers are not required to test cleaning effectiveness on the
same setting that they rate energy-efficiency. Claims about performance
may be based on a heavy-duty cycle, while the energy ratings are based
on the normal setting.
Installing A
Dishwasher
When installing a
dishwasher, try to locate it away from the refrigerator. Dishwashers produce
heat during operation which, if placed too close to a refrigerator, will
increase its energy consumption. If it is not possible to locate the dishwasher
away from the refrigerator, you may be able to add extra insulation to
the top, sides, and back when it is installed. This will both save energy
and reduce noise levels.
Using a Dishwasher
for Maximum Energy Savings
- Try to use the
energy-saving cycles whenever possible.
- If your dishwasher
has a booster heater, turn down your water heater thermostat.
- Use the no-heat
dry-air feature on your dishwasher if it is available to you. If it
is not available, you can turn the dishwasher off after the final rinse
cycle is completed and open the door to allow the dishes to air dry.
This will increase drying time, and according to some in the industry
increase spotting, but try this method sometime to see how well it works
in your machine.
- Do not pre-rinse
dishes. Dishwashers today do a great job cleaning even heavily soiled
dishes. Just scrape off food and empty liquids--the dishwasher will
do the rest. If you must rinse the dishes first, use cold water.
- Wash full loads
only. You will be surprised to learn that you may save energy by putting
dishes in the dishwasher throughout the day and turning it on only once
in the evening, rather than washing dishes by hand throughout the day.
- Load dishwasher
according to manufacturer's instructions. Completely fill the racks
to maximize energy and water use, while being careful to allow proper
water circulation for adequate cleaning.
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