How To Green Your Dishwasher
by Jacob Gordon, Nashville, TN on 02. 6.07
What’s the Big Deal?
Washing dishes uses water, energy, chemicals, as well as your valuable time, so an efficient approach can save a lot of each. Since dishwashing machines are the norm for the majority of people, most of our tips will be for these. Large appliances like dishwashers account for a huge chunk of your home usage, but if used properly and maintained, a dishwasher can be more environmentally friendly than hand washing. Here are ten tips and some more in-depth knowledge to keep that dishwasher running green.Guide Navigation
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1. Go for the full load
Before running the dishwasher, wait until you have a full load (same rule of thumb for the clothes washer). This will help make the most of the energy, water, and detergent the machine uses.
2. Choose your washer wisely
Choose a dishwasher that is rated for energy and water efficiency. In the US, you can start by looking for Energy Star rated appliances, which use 25% less energy than the mandated minimum. Also, know how to read the yellow EnergyGuide sticker you’ll find on all new dishwashers--as well as other appliances.
3. Join the clean plate club
Go for dishwashing liquid and powder that is natural, biodegradable, and free of petroleum and phosphates. Also look for products sold in bulk to save on packaging. Powdered detergents are lighter and so require less energy to ship. For more, see How to Green Your Cleaning. If you are running into spotting problems using phosphate-free detergents, try using a natural residue eliminator like Wave Jet.
4. Skip the pre-rinse
Most dishwashers today are powerful enough to get the all the gunk off, so a lot of pre-rinsing by hand is often just a waste of water and time. Plus, if you rinse all of the dirt off, your dog will have nothing to lick while you’re throwing those plates in.
5. Turn down the heat
Most modern dishwashers have booster heaters to heat the water that comes from your home’s water tank. Seems pretty redundant, right? Turning the water tank’s thermostat down to 120 degrees results in additional energy savings without compromising on cleanliness.
6. Air dry
Instead of letting your washer use electric heat or a fan to dry the dishes, just open the door at the end of the washing cycle and let them air dry. Leave the dishes to dry overnight and they’ll be ready for you when you wake up.
7. Picking the right size
Choose the size model that fits your needs. A compact model is more efficient than a large one unless you have to run it several times a day. For a single person, this might be just right.
8. One glass fewer
Using fewer dishes and utensils over the course of the day means doing fewer loads in the dishwasher, saving energy, water, and detergent.
9. Keep those large appliances away from each other
Putting your dishwasher next to your refrigerator will make the fridge have to work harder due to the heat coming off the washer.
10. Off-peak washing
Delay the start of your dishwasher for off-peak utility hours (some units have timers that will start the cycle at a programmed time). Some utilities even offer reduced rates for energy used during this period, and this is likely to become more and more common in the US.
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1. If you dishwasher is more than ten years old, it makes sense to chuck it (by donating it to a charity for reuse or recycling it for scrap metal, of course!) in favor of a new, efficient model. Today’s units use far less water and energy than older models, also saving you money on your utility bills.
2. Choose appliances that run on natural gas. This may not be possible in houses not piped for it, but typically natural gas appliances uses energy more efficiently than those that run on electricity.
3. A passive solar heating system can provide the hot water you need for your dishwasher, sparing the hot water heater. For more, see How to Green Your Heating.
4. Greywater captured from dishwashers can be used to water the garden and the lawn (but check your local laws for what's permissible). For more, see How to Green Your Water.
1. Replacing a 1994 dishwasher with a current model can save $25 in energy costs and 1,000 gallons of water annually. (link)
2. 80% of the energy used by dishwashers goes to heating the water. (link)
3. Using a fully-loaded dishwasher, without pre-rinsing, uses on average 35% less water than hand-washing all of those dishes. (link)
4. An Energy Star dishwasher can save up to $100 in water and electricity bills over its lifetime compared with a standard dishwasher. (link)
5. Running your dishwasher only when full could save up to 400 gallons a month. (link)
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1. The grunge match: Research conducted at the University of Bonn in Germany found that even the most frugal hand washer couldn’t compete with a modern dishwashing machine in efficiency. TreeHuger’s Christine Lepisto writes: “The Bonn study proves that the dishwasher uses only half the energy and one-sixth of the water, less soap too. Even the most sparing and careful washers could not beat the modern dishwasher.”
2. In the US, new appliances are sold with a yellow Energy Guide sticker that displays the unit’s energy consumption as well as the estimated operating cost per year. Here’s a link to how to use it.
3. "Smart” washers with dirt sensors were found by Consumer Reports to use “significantly more energy for heavily soiled loads than did nonsensor models.” This extra consumption is most often not reflected in the EnergyGuide sticker rating. Consumer Reports suggests skipping this fancy feature when shopping for a new machine.
4. Consumer Reports estimates that 80% of a dishwasher’s energy consumption is in the heating of water, both within the machine and in the home’s water heater. The other 20% is consumed by the motor and drying heater or fan. Of the models CS tested, washers used 31.5 to 12 gallons of water per load. They estimate that the annual cost of operation could range from “$25 to $67 with a gas water heater or $30 to $86 with an electric water heater.” (Consumer Reports)
5. Putting non-reusable containers like water bottles in the dishwasher, especially under heat, may cause them to break down and leach harmful chemicals. Be sure to put only dishwasher-safe items in the machine, especially if you plan to eat or drink from them. Also, you may want to seek out a dishwasher with a non-plastic interior for the same reason.
6. While phosphates are no longer permitted in laundry detergents in the US, they are still allowed in automatic dishwashing soaps (some states differ on the legally acceptable levels). Phosphates are additives that fight the effects of the minerals found in tap water—the minerals that cause hard water and the related spotting on dishes. Phosphates, however, also come from the same family of chemicals commonly used by farmers to fertilize crops. When phosphates wind up in waterways like rivers and coastal areas, they can “fertilize” algae populations, leading to large algal blooms which in turn can choke out plant and animal life in aquatic ecosystems. This is called eutrification, and along with agricultural runoff, can contribute to aquatic dead zones.
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The secret to getting clean dishes while saving water and energy is a synthesis of good practices and good design.
This TreeHugger offers the tip of washing your dishes on the light cycle, no matter the size of the load. Comments by readers offer enlightening input on other ways to lighten the load as well as why some habits are hard to break.
Although we have our doubts about plastic-wrapped food, the Surreal Gourmet offers recipes for how to cook using your dishwasher.
Hitachi has announced the development of a compact dishwasher that uses nano- sized (one billionth of a meter) water droplets to clean dishes.
Have a question about kitchen appliances? TreeHugger helps out with a post on kitchen gear.
Part of General Electric’s Ecomagination initiative, the SmartDispense dishwasher is not only water and energy efficient, it holds 45 ounces of liquid detergent and releases “just the right amount” per load.
In 2004, the winner of the Electrolux Design Laboratory competition was a dishwasher that utilizes cloased-loop, super-critical carbon dioxide to clean dishes, using no water or detergent.
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The federal Energy Star program provides a list of energy and water efficient dishwashers and a some tips for how to maximize savings.
The American Council for an Energy-Efficient Economy compiled a list of the most energy-efficient dishwashers for 2005. Many of these are even better than the Energy Star requirements, and some of these have an annual energy cost of only $17.
Flex Your Power, a California energy-efficiency campaign, offers several tips on how to green your dishwasher.
An article by the US Federal Trade Commission and the US Department of Energy on how to lower your electric bill and purchase efficient appliances.
US Environmental Protection Agency Water Sense program (like the Energy Star program, but for water-consuming products) provides water conservation tips and products under review.
MetaEfficient reviews the book, Solar Water Heating.
A great article from Grist examines the issue of phosphates in dishwashing detergent, why they are trouble, and what can be done about it.
An article from the Michigan Environmental Council compares phosphate levels in various brands of conventional dishwashing detergent.
The Organization for the Assabet River illustrates some of the ill effects of phosphate pollution and lists conventional as well as phosphate-free detergents.
(a rooftop solar water heating system from Omega 2000)
We have not personally tested all these, so let us know about your experiences. The following links are places where you can get green dishwashers, dishwashing products, and related resources. We are not endorsing any particular products, these are just companies that are pushing the edge of sustainability.
GE’s Ecomagination Dishwasher page
Solar hot water heating systems are available from Gaiam, as well as many others
using "gray" water from the dishwasher and/or the washing machine IS ILLEGAL in many jurisdictions and can result in homeowner liability.
at least in the case of washing machines, the reason is that feces from clothing can sometimes be washed out in a large enough quantity ( i.e. baby clothing, elder care clothing, etc.) to result in feces contaminated ground around the home. and feces, aside from being smelly, carries viruses and bacteria.... especially if the donor was sick with infectious illness. the result: potential human & pet infections from playing on the ground, gardening, or pets walking through the contaminated area & back into the home.
A phosphate-free dishwashing powder can be made from the following ingredients:
1 cup borax
1 cup baking soda
1/4 cup table salt
1/4 cup citric acid
a few drops of an essential oil - I like tea tree oil
Mix in an airtight container (I re-use an empty peanut butter jar). Use 2 tablespoons per load.
Rose, could you substitute washing soda for baking soda to get a cleaner clean? Do you find you need any kind of rinse aid with this recipe? Thanks, David
You need to add vinegar to the last rinse, or you will end up with residue on the dishes.