Nov. 5, 2007 Dell has released its first consumer PC to meet the U.S. EPA's Energy Star 4.0 energy efficiency standards.

The new Inspiron 531 operates on an 80%-efficient power supply and comes preconfigured to switch to a low-power sleep state after 15 minutes of inactivity. To save paper, the machine is equipped with an electronic owners manual. (Ringing up at just $369, the Inspiron 531 is also considered very affordable.)

Dell is offering Inspiron buyers the opportunity to offset the emissions from powering their PC through the company's "Plant a Tree for Me" program. Donations go to the Conservation Fund and Carbonfund.org, nonprofit organizations that plant trees in sustainably managed reforestation projects.

In June, Dell announced a long-term goal to become the "greenest technology company on the planet," saying it aimed to make its products carbon neutral.

But the company is still trailing rival Hewlett-Packard in the energy efficiency race; HP unveiled its Energy-Star compliant PC in March of this year, three months ahead of schedule.