The U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley, California, U.S.) has released a report which finds that solar photovoltaic (PV) systems significantly contribute to the selling prices of homes in the U.S. state of California.

"An Analysis of the Effects of Residential Photovoltaic Energy Systems on Home Sales in California" finds that homes that include PV systems have sold at an additional USD 3.9 to USD 6.4 per watt of the system, compared to an average investment of USD 5 per watt over the 2001-2009 period.

“This is a sizable effect,” says Berkeley Lab Staff Scientist Ryan Wiser, a co-author of the study. “This research might influence the decisions of homeowners considering installing a PV system and of home buyers considering buying a home with PV already installed."

Premium less noticeable in new homes

The study also notes that the increase is less noticeable in new homes, which averaged a premium of USD 2.3 - 2.6 per watt, as opposed to existing homes, which averaged between USD 6.4 and USD 7.7

Study based on 72,000 California home sales

Berkeley Lab's study uses a data set of approximately 72,000 California homes, 2,000 of which had PV systems installed at the time of sale. Researchers state that they controlled for a large number of factors that might influence decisions, such as housing market fluctuations, neighborhood effects, home ages and sizes, and land parcel characteristics.

Berkeley Lab states that its findings are in line with those from another study in 2010 by Dastrop et al. focused on homes in the San Diego area which uses similar methods.

The authors also recommend exercising caution when applying the results of this study to other locations or market conditions.

The study has been praised by industry organizations including the Solar Energy Industries Association (SEIA, Washington D.C., U.S.) and the Vote Solar Initiative (San Francisco, California, U.S.).