We’ve got ample evidence that green homes command more cash in the state of Oregon, as per data from the Earth Advantage Institute last year revealing that homes with a recognized third-party certification brought in as much as 30 percent more than their non-certified counterparts in 201o and 2011. Now the numbers are in for California.

According to a recent study conducted by economists at the University of California, Berkeley and University of California, Los Angeles, California homes certified green by a recognized third-party sell for an average of 9 percent more than comparable, non-labeled homes. Certifications covered in this study include Energy Star, LEED for Homes and GreenPoint Rated. (Apparently, not enough homes have been certified under the National Association of Home Builders green standard to be included.)

image via Carver + Schicketanz

These numbers may sound lower as compared to the Earth Advantage study of Oregon, but it’s worth noting that, on average, the Golden State actually boasts higher stats. That’s because the green homes commanding an average of 30 percent more in Oregon are concentrated in the Portland metro area; green homes in Oregon on average pulled in about 8 percent more than conventionally built homes, a whole percentage point behind California.

According to the California study, the average conventionally built home in California sells for around $400,000, while a home bearing one of the three green certification listed above goes for around $434,000. Like the Oregon study, however, this one shows that the green premium associated with certification varies greatly from region to region — and in this case, that homes in the hottest regions command the greatest premiums. This seems to fly in the face of the uber-green reputation of the cool, foggy Bay Area (and Northern California in general), but the authors speculate that this may be due to the increased costs of keeping a home cool.

Which is to say, when the cost of electricity is as high as it is in California, energy efficiency becomes an extremely attractive feature in a home.

The full text of the study is available online [PDF].