PCs typically cost some £20 a year in energy costs, and the cost to the environment is – arguably – even higher.

This is where the Green PC 478 tries to remedy things.

It’s designed to be energy efficient without sacrificing things, performance-wise.

It has a low power Intel Core 2 Duo T5500 processor, which runs at 1.66GHz, and which Intel originally designed for cheaper notebook computers. There’s also 1GB of memory and a 100GB hard disk.

The hard disk is smaller than what comes with most desktop PCs, but that’s because it’s a quieter and less power-hungry notebook version.

The Green PC's book-like physique makes it small for a desktop PC, and the black and grey styling is a little dull. Only the blue-lit power button spices things up a little. The front of the PC houses a DVD writer and a multi-format card reader, which will makes it handy for digital camera users. The PC is whisper quiet thanks to its minimal use of fans, making it viable as a bedroom PC.

It might also be used as a media centre PC for the living room, since there’s an HDMI port on the back to connect it to a high-definition TV set. Outputs for Dolby-certified surround sound mean it’s good home theatre material.

Windows Vista Home Premium comes installed, with its Media Center software making it easy to watch films, photos or listen to music. It lacks a TV tuner and remote control, although these are option extras. Kaspersky Anti-virus and the Nero 7 media suite make up a software bundle that's a little limited.

There isn’t a DVI output for monitors, but the computer does come with a HDMI-to-DVI cable, which works just as well, and there is an older-style VGA socket. There are six USB ports in total, two on the front and four on the rear, and a Firewire port for connecting a digital camcorder.

In our lab tests the system performed acceptably for office tasks and video playback, although it’s not as fast as similarly priced competitors, scoring more like a notebook. The onboard graphics processor (as distinct from an add-on graphics card) couldn’t cope with any of our gaming tests and there isn’t a PCI Express slot, so upgrading to a proper graphics card is out of the question.

The Green PC 478 consumes around half the power used by a typical desktop, coming out at the power usage of a standard notebook, meaning a saving of a few pounds a year in power.

There are alternative quiet PCs from Evesham and Tranquil that consume even less power, but they don't have the performance of this one.

Unlike Evesham and Tranquil, Very PC doesn't plant trees to offset the carbon dioxide produced by powering the computer, branding the tree-planting approach used by its competitors as a 'gimmick'.

According to UN research, the carbon dioxide produced when a PC is manufactured vastly outweighs the carbon dioxide produced in powering a PC over its lifetime. So, on an environmental basis, buying this PC will only make matters worse. That said, compared with similar computers this is a greener option.

Ultimately, though, if it wasn’t for the generous three year return-to-base warranty Very PC provides, the Green PC 478 would only represent average value for money. A notebook with the same processor and hard disk and similar energy consumption can be bought for the same price.