Homeowners in California who invest in photovoltaic systems are netting up to 6.4 percent more in resale value for their homes than for similar homes sold without solar systems, according to a new study by Lawrence Berkeley National Laboratory, in Berkeley.

“We find compelling evidence that solar photovoltaic systems in California have boosted home sales prices,” said Ben Hoen, the lead researcher on the study and a principal research associate at Berkeley Lab. "The irony is that we found that premiums were smaller for new home sales than for existing home sales, and the big question was why," he said. "In discussion with homebuilders, we surmised that PV is being used not to boost sales price but differentiate from other homes. The developers have a lot of money wrapped up in new homes, so if a relatively low-cost PV system will help it sell, they install it," he explained.

Based on analysis of 72,000 homes sold in the state, the study reported, "The (premium sale price) effects range, on average, from approximately $3.9 to $6.4 per installed DC watt of PV, with most coalescing near $5.5 per watt, which corresponds to a home sales price premium of approximately $17,000 for a relatively new 3,100-watt PV system (the average size of PV systems in the study)."

This premium sales price was slightly higher than the installation cost, the study determined: "These average sales price premiums appear to be comparable to the investment that homeowners have made to install PV systems in California, which from 2001 through 2009 averaged approximately $5 per DC watt… homeowners with PV also benefit from electricity cost savings after PV system installation and prior to home sale."

Approximately 2,100 megawatts of grid-connected solar PV have been installed in the United States.  California has been and continues to be the country’s largest market for PV, with nearly 1,000 MW of installed capacity.  California is also approaching 100,000 individual PV systems installed, more than 90 percent of which are residential. Only 2,000 of the sold homes analyzed in the study had PV installed, with the study period ranging from 2000 to mid-2009.