Do New-Construction Homes in California Need Solar?

California’s Building Energy Efficiency Standards (Title 24, Part 6, often just called the Energy Code) first required solar PV on new low-rise homes starting with the 2019 code, which applied to building permits pulled from January 1, 2020. The 2022 code pushed further into battery-ready and electrification-ready wiring, and the 2025 code — effective for permit applications on or after January 1, 2026 — carries the solar requirement forward and expands storage provisions.

Under the currently adopted code, a solar PV system is prescriptively required for newly constructed single-family homes and most low-rise multifamily buildings. Battery storage itself is generally not mandatory for a single-family home, but new homes typically must be battery-ready (the panel and conduit prepped for a future battery). Battery storage is required for some other building types — such as new nonresidential and high-rise multifamily buildings. Because thresholds and applicability change with each code cycle and your project type, treat this as general information: the exact requirement follows the currently adopted Energy Code and is confirmed by the Title 24 analyst on your compliance documents (the CF1R), not as a fixed universal rule.

Unlike a retrofit — where you size solar to shave down an existing electric bill — a new-construction system is sized by code formula. The Energy Code takes the smaller of two numbers: (1) what fits on the usable roof area (a fixed watts-per-square-foot figure), and (2) a calculation driven by your climate zone, the home’s conditioned floor area, and how many dwelling units it has. A bigger, mixed-fuel home in a hot climate zone generally calls for a larger array than a compact home in a mild zone.

Because the size is set to roughly offset the modeled electrical use of the home — not necessarily your real habits — the included system may or may not cover an all-electric lifestyle, an EV, or heavy AC. If you expect high usage, it’s worth asking whether the array can be upsized at build time, which is almost always cheaper than adding panels later. For a usage-based sanity check, see how many solar panels a California home needs.

A builder can satisfy the solar requirement in different ways, and the ownership structure changes what you actually get. If the panels are owned — bought outright by the builder and rolled into your purchase price (and mortgage) — you own the system and its production. If they’re on a lease or power-purchase agreement (PPA), a third party owns the hardware and you pay them for the power or a fixed monthly fee, often with an annual escalator. A leased system can also add a step when you sell, because the agreement usually has to be transferred or bought out.

One more 2026 wrinkle: the 30% federal Residential Clean Energy Credit ended for owner-bought systems on December 31, 2025 (IRS). For a new home where the panels are bought and bundled into your price, there’s no homeowner credit to claim in 2026. With a lease/PPA, the third-party owner may qualify for a separate business credit, but you don’t claim it directly — more in the 30% credit ended, explained. None of this is tax advice; confirm with a professional.

The tariff you land on shapes how much the panels are worth. In the investor-owned utilities — SCE, PG&E and SDG&E — new solar goes on the Net Billing Tariff (NEM 3.0), which prices imports and exports separately: you pay retail for power you pull in, and earn a time-varying export credit that is usually far below retail (an illustrative 5–8¢/kWh at common midday hours, with a few late-summer evening hours worth much more). That math is why a battery — or at least battery-ready wiring — carries more weight on a new build than it used to; see NEM 3.0 explained. In LADWP territory (a municipal utility), solar is credited under its own municipal solar rate schedules rather than the CPUC tariff — confirm the current schedule for the address.

If you’re buying or building a new California home, expect solar to be part of the package — that’s the Energy Code doing its job. The value you get, though, depends on the details: whether you own the system, how it’s sized against your real usage, the equipment and warranties, and whether storage is included or just wired for. Ask for the Title 24 documents and the solar contract early, and treat any savings, size, or timeline figures as estimates, not guarantees — they depend on the specific home, utility and tariff. If you want a second opinion on an included system or a quote to expand it, the Cali Energy team can review it with you.