The Wonderwash operates by stowing your dirty clothes in the barrel, with hot or warm water and a small amount of detergent and fixing the lid in place. A pressure screw in then tightened on the lid. It is this pressure which the key to the performance of the unit. The notion is that the hot water in the completely sealed and pressurised barrel heats up the air trapped inside. This pressure forces the water and the detergent through the fabrics and separates the dirt and grime rapidly. Rotating the barrel with the handle further agitates the mixture of water, detergent, fabric and dirt. About 2 minutes rotation is supposedly all that is required. The pressure screw is released and the dirty water emptied. The Wonderwash can also be used for rinsing laundry. But it is not a mini tumble drier.
When I was lecturing in eco-design, the Wonderwash made a great case study for innovative thinking. Taking the notion of pressure cooking in the kitchen and applying it to the laundry. It can use 45,000 less litres of water per year, compared to a standard top load washing machine, a saving of nearly 80%. There is also a corresponding saving of roughly 65% in energy and 45% in detergent use.
The down sides are that it uses hot water (tsk tsk) and in the past there have been some issues with the longevity of the plastic structure. Maybe these have been resolved since my days of using one as my sole washer. Laundry Alternative offer them for $43 USD and Lehmans have a made in the USA model, called Wonder Clean for about $45 USD. Plus they have the much more robust James Hand Washer for the tidy sum of $450 USD, but this is more than it sounds like you need
May your wash day blues be a thing of the past, Justin.