Computer manufacturer Fujitsu-Siemens has announced a new labelling system to show buyers which of its products are the most environmentally friendly.

The 'Green IT' label will be used to rate products including the company's Amilo and Lifebook desktop and laptop computers.

Some computers will not qualify for the green label, but those that do will be marked with a Green IT badge showing either one, two or three stars. The rating takes into account the energy consumed during the entire life of each product, from its manufacture to eventual recycling.

For example, a three star-rated product must use halogen-free material, have manuals printed on chlorine-free paper, and it must be possible for one person to disassemble the computer for recycling using commonly available tools. All plastic parts weighing over 25g must be labelled for recycling.

A three-star product must also be energy-efficient during use. Three-star PCs must operate at 80 per cent power efficiency and notebooks at 85 per cent, whether they are running at 20, 50 or 80 per cent of their possible speed.

The company claims that in some respects its scheme is one of the strictest environmental ratings schemes in existence. For example, the Nordic Swan qualification makes an exception for hazardous materials used on printed circuit boards, while Fujitsu's scheme does not.

Fujitsu-Siemens says it chose to create its own rating system after finding that none of the currently available schemes was suitable, with some setting impossibly high targets and others using certifications that are so limited as to be worthless.

“It is possible to develop a three-star system today, but it is not trivial to have one star on every system,” said Fujitsu-Siemens vice president Dr Berndt Kosch. “If you look at some other systems, some are so trivial that every product is labelled.”

Of the 30 systems already tested, only six have been awarded the top three -star rating. “If products don't carry the label, this is also an indication,” said Dr Kosch.

The company says it will publish the specification for the labels, and is inviting other companies to use the scheme, but Dr Kosch told Computeractive that he did not expect the company's competitors to join. He also acknowledged the dangers of an individual approach.

“The bad thing would be if everybody comes up with their own label,” he said. “I hope they are compatible.”

In a statement, Fujitsu-Siemens' chief technology officer, Joseph Reger, said that the company “would not hesitate in adopting a suitable industry-standard labelling system, should one be introduced in the future”.

Greenpeace said the scheme could be helpful "In as much as it helps a potential Fujitsu-Siemens customer to differentiate between the different levels of 'green goodness' of their products", but said the company should go further.

"I don't think Fujitsu-Siemens creating more labels is especially helpful", said a spokesperson. "Why doesn't it make all its products 3-star - then it wouldn't need to rate the more regressive models?"