Mirror, mirror on the wall; who is the greenest vendor of them all? Toshiba has had five of its notebooks rated gold by EPEAT, the environmental agencies top green rating. And claims that this is more gold-rated notebooks than any other supplier can boast.

Apple can only claim 5 silver-rated laptops to its name.

EPEAT is a US PC environmental rating organization. The US government has mandated that federal PC purchases must be of EPEAT-rated PCs, encompassing desktops, notebooks and monitors. The agency has a searchable database of products rated gold, silver or bronze in terms of their environmental friendliness.

A gold rating means a product passed 23 mandatory criteria in eight categories, as well as 75 percent or more of the 28 optional EPEAT criteria.

Mark Simons, Toshiba Digital Products Division VP and GM, said: "The EPEAT Gold status is a milestone Toshiba is truly proud of, and we are looking forward to continually making strides to protect the world we live in for future generations."

Is Toshiba the greenest notebook supplier of all?

Delving into EPEAT's database reveals different ways of answering the greenest notebook supplier question.

- Acer has no EPEAT-rated product at all
- Apple has 5 silver-rated notebooks
- Dell has 2 gold notebooks and 12 silver notebooks
- Fujitsu Systems Corporation America has 16 notebooks rated silver
- HP has 23 silver-rated notebooks
- Gateway has 28 bronze-rated notebooks
- Lenovo has 48 notebooks rated silver and one bronze, the highest number of any supplier
- Toshiba has 5 gold notebooks, 15 silver-ranked notebooks and 4 bronze ones; that's 24 in total.

On the face of it Acer is the least green notebook supplier and Lenovo could be seen as the greenest as it has the largest numbers of EPEAT-rated notebooks.

But what is a product? Clearly a Toshiba Tecra is a different product from a Toshiba Portege but is a Portege with twice the RAM of another Portege a different product from it?

It is in terms of a sales stock keeping unit (SKU) in that it has a separate product ID and price and reference in Toshiba's catalogue of products. But it isn't really a separate product in a manufacturing sense, merely one product in two guises.

Since manufacturers certify catalogue product items - SKUs - against the EPEAT tests then we should take the numbers with a pinch of salt. There is no industry standard definition of an SKU. Lenovo SKUs differ from Toshiba's which differ from Apple's.

Also the EPEAT figures don't show the proportion of a manufacturer's products that are EPEAT rated and those that are not.

Why is Acer an absentee from EPEAT ratings? This year it issued a 74-page Corporate Environmental Report J T WAng, Acer's chairman and CEO, writes in it: "we fully understand the importance of reducing the emission of greenhouse gases and preventing the deterioration of global warming problem. So, with the management and requirements of global suppliers, we develop IT products with high energy-saving performance to minimize the emission of greenhouse gases during the life cycle of products."

Yet EPEAT isn't mentioned in the report.

Acer states on its website that it advises customers to choose e-waste recyclers registered with EPEAT Also it will adhere to controls on hazardous substances from many environmental authorities, including EPEAT.

With Acer saying it is taking so many environmental initiatives it is odd that an EPEAT rating isn't one of them. It doesn't mean that Acer is any less of a green notebook supplier than Apple, HP, Toshiba and the others mentioned above, merely that Acer does not have any EPEAT-rated products. That may well change. (We were unable to get in touch with Acer for this story.)