A washing machine that cleans clothes by pounding them with plastic chips could save billions of gallons of water a year, its inventors claim. The Xeros uses less than 2 per cent of the water – and energy – of a conventional model and leaves clothes almost dry, doing away with the need for a dryer. The machine uses thousands of reusable plastic chips to remove and absorb dirt. Tests have shown the machine can shift virtually all types of everyday stains, according to a team at Leeds University.

Professor Stephen Burkinshaw, who invented the machine – which uses one cup of water each cycle – said: “The performance of the Xeros process in cleaning clothes has been quite astonishing.

“We’ve shown that it can remove all sorts of everyday stains including coffee and lipstick while using a tiny fraction of the water used by conventional machines.”

About 20kg of the chips are added, along with a cup of water and detergent. The chips can be used up to 100 times, the equivalent of six months’ washing.

Xeros Ltd, the company developing and marketing the machine, believes it could be on the UK market as early as 2009 and expects it to be used in the washing and dry-cleaning industries.

At MetaEfficient, I evaluate appliances based on a number of factors, namely: energy efficiency, effectiveness, reliability, and price. This holds true for washing machines, because all of these factors need to be considered and weighed against each other (I’d also like to include lifecycle analysis, but  there’s no information available for washers). For raw efficiency data, one can turn to the Energy Star ratings, to work out which machines use the least amount of energy and water overall. Based on the Energy Star data, the most efficient washing machines for 2008 are made by LG Electronics and Kenmore.

Three LG washers received the best Energy Star ratings, and four Kenmore washers followed very close behind the LG machines. These ratings are based on the Modified Energy Factor (MEF) which is a way to compare the relative efficiency of different units of clothes washers (higher is better). The second factor is the Water Factor which is the number of gallons per cycle per cubic foot that a washing machine uses (lower is better). Here is a listing of the highest rated washing machines according the February 2008 update:

1. LG Electronics TROMM SteamWasher WM248#H, 2.65 (MEF), 3.6 (Water Factor)
2. LG Electronics Stainless Steel SteamWasher WM0001H: 2.65 (MEF), 3.4 (Water Factor)
3. LG Electronics TROMM SteamWasher WM268#H: 2.65 (MEF), 3.3 (Water Factor)
4. Kenmore Washer Model 4757*70+: 2.6 (MEF), 3.7 (Water Factor)
5. Kenmore Washer Model 4756*70+: 2.6 (MEF), 3.7 (Water Factor)

(Model numbers often contain wildcard characters, such as *, #, and X, that are placeholders for non-energy attributes, such as color. )

In this analysis, I’m excluding Energy Star washers with a load capacity of less than 3 cubic feet, these compact machines get high energy ratings but are inefficient in their water use.

You’ll notice that all of these machines are front-loading washers, the ConsumerSearch product review guide says:

Experts generally agree that front-loading washing machines (also called horizontal-axis washing machines) are better than top-loaders. Front-loaders use a dryer-like action to tumble clothes in and out of water and detergent, while conventional top-loaders circulate clothes with some type of agitator. Because gravity is used to tumble the laundry, front-loaders are gentler on clothes and cause less tangling than top loading machines. In addition, their fast spin speeds remove more water from clothing, thereby reducing drying time and resulting in further energy savings. Because of the design, you can’t soak clothes and you have to use special low-sudsing “HE” or high-efficiency detergents.

Let’s look at the most efficient washers in more detail, followed by an efficient washer we think is the best value for your money:

LG TROMM SteamWasher

This is an innovative washer: it uses stream to wash your clothes, and this process makes it the most efficient washer available. The steam cleaning is gentle on your clothes, and tend to remove wrinkles. The washer uses only 145 kWh of energy per year, and 4,690 gallons of water per year on average. This is significantly better than conventional washers. The SteamWasher is also the largest capacity front-loading machine with 3.63 cubic feet of space. It can spin your clothes at 1200 rpm, which means you’ll save on drying energy and time. The problem with this washing machine is that it’s expensive. It has a recommend price of $1600, and most retail stores sell it for around $1400 currently. A better option might be to get a lower cost but still very efficient LG machine (see our review of one below).

In terms of reliability, ConsumerSearch says: “The LG TROMM SteamWasher hasn’t been on the market long enough to establish a reliability track record, but the J.D. Power’s major appliance study showed that LG washing machines in general have the highest customer satisfaction rating of all brands.”

The LG TROMM SteamWasher is available from Sears.

Kenmore High-Efficiency Washers

The Kenmore “High-Efficiency” washers live up to their name, and have a reasonably good track record in regards to reliability. The Kenmore machines use 69% less water and 60% less energy per load compared to conventional top load washers. They also spin at 1000 rpm, which means less energy will be spent drying your clothes.

The Kenmore front-loading washing machines are priced at $600-$900, and only available from Sears.

LG Supercapacity Front Load Washers

LG Electronics makes less expensive washing machines that are also highly efficient. For example, the front-loading LG WM0642HW (estimated retail $850) gets good reviews. It’s more affordable because it has fewer bells and whistles, and because it has a small door and window. The LG WM0642HW has a 3.83-cubic-foot capacity, automatic temperature control, an automatic detergent dispenser and a stainless-steel tub. A similar model, the LG WM2016C (estimated retail $780), costs a bit less, but is slightly smaller, with a smaller window.

The LG WM2016C gets a Modified Energy Factor (MEF) rating of 2.25, which is quite good — this machine will only consume 152 kWh / year, and 4323 gallons of water per year on average. That’s only 7 kWh more energy per year than the SteamWasher, and 367 more gallons of water, for half the price. Because of this, the LG WM2016C is the MetaEfficient recommendation for an efficient washing machine.

These LG washers are available from Amazon and Sears.

This washer from LG Electronics uses steam to clean your clothes. Steam washers are common in the industrial world, but this is the first one available for the home. LG says the washer “remove creases from your garments, eliminating the need for ironing” and steam-cleaning “reduces shrinkage and extends the life of your threads”. They also claim it uses 35% less water and 21% less energy than a conventional model. One drawback is that the entire cycle takes two and a half hours.

We don’t have the specs on the washer, so we can’t compare it to some of the very efficient washers we’ve featured previously.

Available in the U.S. from Absolute Home for $1600.

The Staber Washer is good washer if you are interested in saving electricity, water and detergent. It is the only top loading, horizontal-axis clothes washer made in the U.S. It operates in a similar way to an efficient front load washer, but you get top loading convenience. Compared to conventional vertical-axis agitator washers, the Staber uses 66% less water, 50% less electricity, and 75% less detergent. It uses only 12-16 gallons of water per load and 265 kWh of electrical power per year. See this comparison of electrical costs over 3 years.

Here are some reviews and comments on the Staber Washer from Samurai Appliance Repair Man.

This washer is best suited for solar power systems. It requires only 5-6 amps during washing, surges to 11 amps when motor starts. Can run on a 1500W inverter.

Here are some more specs:

Power Consumption: 110-150 Watts per load (265 kWh/year) 1.48 MEF
Water Consumption: 15 gallon per average load
Capacity: 2 cu. ft tub, 18 lb. load
Dimensions: 27″ W x 26″D x 42″ H
Warranty: 25 years on outer tub module, 5 years on bearings & suspension, 1 year on all else.

It costs about $1200.

Product Home Page: Staber.Com

Available from: Alternative Energy Store

A waterless washing machine that removes stains from garments in a few minutes has been developed at the National University of Singapore, the facility said on Wednesday. The appliance uses negative ions, compressed air and deodorants to clean clothes. Industrial design students Wendy Chua, 21, and Gabriel Tan, 23, said they were inspired by the technology in air purifiers, which uses negative ions to clump dirt and bacteria, making it easier for the particles to be sucked out. The ions are a natural cleaning agent. More info here.

This washer is no longer recommended, due to the lack of service and support.

This washer from Fisher and Paykel is very efficient in terms of water use and electricity consumed, costing only about $21 annually in power, and using only 26 gallons per laundry load. The CEE (Consortium ForEnergy Efficiency) rates this washer as the most efficient of its kind.

It has three spin speeds including a 1000 RPM spin to reduce drying time. It retails for about $600. There are a number of first-hand reports about this washer in this discussion at GardenWeb. Here are some specs:

Power Consumption: 298 kWh / year
Annual Energy Cost: $20.86
Water Consumption: 26 gallon per average load, 8.8 (CEE Water Factor)
Dimensions: 36.5″ H, 26″ W, 26″ D
Weight:180 lbs
Capacity: 3 cu. ft tub
Warranty: Full 2 years parts and labor warranty.

Product Home Page: Fisher and Paykel

This washer, created by Jan Čapek and Kryštof Nosál, was designed to look attractive anywhere in your home. It’s called the Washman, and it finished second in the Elektrolux Designer Competition. The washer is targeted at younger users who don’t have space, or only need to do small loads of laundry. It features low water usage, and a high speed spin cycle to reduce the energy needed in the drying cycle. It also has an integrated removable clothes basket with separate areas for socks, shirts, and pants. Still in prototype stage though.

More info: Prague Tribune, story via Treehugger

If the published specifications for this Nexxt washer are correct, it
is a contender for the most efficient AC powered washer available. Bosch
also claims it is the quietest on the market, running at 60 decibels.
This would allow you to install it near your bedroom, due to the low
noise it generates.

Power Consumption: 186kWh/year
Average Water Consumption: 13.2 gallons
Spin: 1200rpm
Drum Capacity: 18 lbs.

Home Page: Bosch
Purchase from: US
Appliance ($1099) or ABT Electronics ($1099)