The short answer
- Older studies found owned solar adds value: about $4 per watt in a Berkeley Lab study of sales through 2013, and about 4% in a 2019 Zillow analysis.
- Those figures are dated: they predate net billing, today's lower prices and the end of the federal credit. No study yet covers homes sold with net-billing systems.
- Leased systems generally don't add value the same way; the buyer has to take over the lease.
- Under net billing, the 9-year export-rate lock doesn't transfer to a buyer. NEM 2.0's 20-year term does.
What the studies found
- Berkeley Lab ("Selling Into the Sun"): 22,822 home sales in eight states, 2002–2013; buyers paid premiums of about $4 per watt, about $15,000 for an average 3.6 kW system (LBNL).
- Zillow (2019): homes whose listings mentioned solar sold for 4.1% more on average (3.6% in Los Angeles), from listings sold Mar 2018–Feb 2019. Company research, not peer-reviewed (Zillow).
Why today may differ
- System prices fell, so the replacement cost a buyer avoids is lower.
- A net-billing system's 9-year export lock belongs to the seller (CPUC); the buyer starts at current export values. A NEM 2.0 system keeps its legacy term after a sale.
- Batteries add backup power, which some buyers value in fire and outage areas.
If you're selling
- Gather the paperwork: the interconnection approval, warranties, production history and any lease or loan documents.
- If it's leased, start the transfer early; the lease company must approve the buyer.
- If a loan put a UCC fixture filing on title, ask the lender how it's released at closing.
New homes
New California homes must have solar under the building code; the 2025 Energy Code (from Jan 1, 2026) also requires battery-ready wiring when electrical service is over 125 A (CEC).
Checked against official sources on Oct 1, 2026. Sources are linked in the text. Not legal, tax or financial advice.