In a study that analyzed 22,000 home sales. The Lawrence Berkely Lab found that homeowners are consistently willing to pay more for homes with solar PV systems. So, solar panels do increase your home value.
The study took place in 8 states from 1999-2013, with 4,000 of the 22,000 homes having PV systems. This is the most comprehensive study thus far, and they found the premium homeowners were willing to pay was around $15k more for a house with a PV system.
There is a very small difference between the PV premiums for new and existing homes. There is however, a sharp depreciation rate as a system ages.
Lastly, there is the existence of what the study calls “a green cache”, meaning home buyers pay incrementally more as a system size increases. So according to this thorough study, solar really does add significant value to your home, in addition to saving you money on your energy payments.