How can you tell if a computer or monitor is “green”? Well, it depends on what you’re looking for.

If it’s energy efficiency, seek out an Energy Star rating. Computers bearing an Energy Star logo today should adhere to the new and more stringent Energy Star 5.0 specification that went into effect July 1.

Want it made from greener materials that are free of toxins? Look for RoHS (Reduction of Hazardous Substances) compliancy that eliminates lead soldering and drastically reduces other toxins such as brominated flame retardants. GreenGuard certification shows that a product emits a low amount of unhealthy airborne particles.

Want a combination of criteria? Check out the EPEAT ratings, which evaluate computers by up to 51 different criteria, including energy efficiency and reduction of toxins.

And if you want to get really picky, see Greenpeace ratings for some computers.

Here are five computers — actually one notebook, two desktops, one all-in-one, and a computer monitor — that are pretty darned green.

Click here to view 5 Great Green Computers.

Related: How to Find Energy Star Computers

Steven Castle - Contributing Writer

Steven Castle is Electronic House's managing editor. he has been writing about consumer electronics, homes and energy efficiency topics for two decades. He is also the co-founder of GreenTech Advocates.