It’s not a message that environmentalists want to hear, but new research shows that most people would be far greener to use a dishwasher instead of washing up by hand.

Some people who wash their dishes by hand are sending the environment down the drain says a Nature News Service report. Hand dish-washers can consume more than ten times the water and twice the energy of a dishwasher.

Home-economics technologist Rainer Stamminger of the University of Bonn, Germany says, "People need to start thinking about their washing-up habits. If we can change their behaviour, we can do something for the environment."

Volunteers from seven European countries were asked to wash 140 pots, plates, glasses and items of cutlery - the typical daily load of a family of four - splattered with seven common foods, including oats, spinach and egg, and left to dry for two hours. Rainer Stamminger videotaped the exercise and monitored water, energy and soap consumption.

The results were surprising:

• There was a large spread in water usage from 15 litres to 345 litres. The standard consumption for a European dishwasher is only 12-20 litres of water.
• Hand-washers consume about 2.4 kWh of energy - twice as much as dishwashers. And less than 15% got their dishes as squeaky-clean as the machine.
• Lots of soap and water do not guarantee a clean dish. Stamminger recommends using two water baths: a hot and soapy wash, and a cold rinse to conserve energy.

The Danes tend to use less water than the French do. But Stamminger warns against seeing this a regional variance. Washing up is more of an individual practice than something that characterises a particular region. "People do what they learned growing up," he comments.