Do New-Construction Homes in California Need Solar?
Straight answer: yes. Under California’s Energy Code every new single-family home needs a solar PV system — a rule in force for permit applications since January 1, 2020 and carried into the 2025 code that applies from January 1, 2026. The required size is small: the smaller of a formula based on floor area and climate zone and what fits on the sunny roof — about 2.6 kW for a 2,000-square-foot home in the San Fernando Valley. A battery is not required, but a home without one must be wired battery-ready.
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- Required: the Energy Code prescribes a solar PV system for newly constructed buildings — under the 2019 code for permit applications from January 1, 2020, and under the 2025 code from January 1, 2026.
- Size: the smaller of a formula (floor area and dwelling units, weighted by climate zone) and the sunny roof area times 18 watts per square foot on a sloped roof — about 2.4–2.7 kW for a 2,000-square-foot home across Los Angeles’ climate zones.
- Exceptions: no PV when the sunny roof is under 80 contiguous square feet or the size comes out under 1.8 kW, and the size may be cut 25% with a qualifying battery of at least 7.5 kWh.
- Battery-ready: a new home with service over 125 amps and no battery needs backup circuits, a 225-amp main panel and space for a transfer switch.
- For buyers: the code minimum follows floor area and climate zone, not your EV, pool or household size; check who owns the system and how big it is.
Is solar required on a new home in California?
Yes, with a handful of exceptions, and it has been since 2020.
The California Energy Commission states that a solar PV system is prescriptively required for all newly constructed buildings; a building that qualifies for an exception still has to meet the solar-ready requirements so panels can be added later (CEC). For homes the rule first applied to permit applications dated on or after January 1, 2020, under the 2019 Standards (CEC), and the 2025 Energy Code carries it forward for applications on or after January 1, 2026 (CEC). Multifamily buildings have a parallel requirement in §170.2(f). Batteries are prescriptively required for new nonresidential and high-rise multifamily buildings; new single-family homes that do not install one must be battery-ready instead.
How the required size is set
A formula, a roof check, and the smaller of the two.
Section 150.1(c)14 of the 2025 Energy Code requires a system no smaller than the lesser of two numbers. The first is Equation 150.1-C: kW = conditioned floor area × A ÷ 1,000 + number of dwelling units × B, with A and B set by climate zone. The second is the solar access roof area — roof that can structurally carry panels, plus covered parking, carports and other new structures on the site, minus any area with less than 70% annual solar access — multiplied by 18 watts per square foot on a steep-sloped roof or 14 on a low-sloped one. On a steep roof, planes facing north, between 300° and 90°, do not count (2025 Energy Code).
| Climate zone | Where | A (per 1,000 sq ft) | B (per home) | Minimum PV |
|---|---|---|---|---|
| 6 | Santa Monica, Malibu, most of Long Beach and Torrance | 0.594 | 1.23 | 2.4 kW |
| 8 | South Los Angeles, Culver City, Inglewood, Compton, Downey, North Long Beach | 0.586 | 1.37 | 2.5 kW |
| 9 | Most of the San Fernando Valley, central Los Angeles, Burbank, Glendale, Pasadena, most of Santa Clarita | 0.613 | 1.36 | 2.6 kW |
| 14 | Lancaster, Palmdale | 0.741 | 1.26 | 2.7 kW |
| 16 | Sunland, Tujunga and mountain areas | 0.59 | 1.22 | 2.4 kW |
Sources: 2025 Building Energy Efficiency Standards, §150.1(c)14 and Table 150.1-C · CEC climate zones by ZIP code. The roof-area limit can make the requirement smaller; the Title 24 documents for the house show the final number.
That is a small system. In Northridge a south-facing 2.6 kW array produces about 4,400 kWh a year (NREL PVWatts), against roughly 6,000 for an average California home, which used 503 kWh a month in 2024 (average home electricity use). The formula knows only floor area, dwelling units and climate zone — not an EV, a pool or how many people live in the house — so upsizing during construction is often worth pricing; see how many solar panels you need.
- No PV is required if the solar access roof area is under 80 contiguous square feet.
- No PV is required if the calculated minimum size is under 1.8 kW DC.
- Roof designs where the building official finds the PV system cannot meet the snow-load requirements.
- For buildings approved by the local planning department before January 1, 2020, shading and roof areas set by the conditions of that approval are taken into account when the sunny roof area is measured.
- The formula size may be reduced by 25% when a battery meeting Joint Appendix JA12, with at least 7.5 kWh of cycling capacity, is installed with it.
Panels somewhere else, credits on your bill
The code lets a builder meet some or all of the solar requirement through a community shared solar or battery program instead of panels on each roof — but only a program approved by the Energy Commission. It has to deliver the same or better energy performance, give the home bill savings larger than its cost, and keep the home enrolled for at least 20 years, whoever owns it; a later owner can leave only by installing solar on the house (2025 Energy Code, §10-115). If a new home has no panels, ask the builder whether it uses such a program and get the terms in writing.
Battery-ready wiring
Required for new homes that skip the battery.
Under §150.0(s), a new home with one or two dwelling units and electric service over 125 amps must provide either battery-ready interconnection equipment with at least 60 amps of backed-up capacity, or a dedicated raceway of at least one inch from the main service to a subpanel for backed-up circuits. At least four circuits — the refrigerator, a light near the main exit and a bedroom receptacle among them — must be grouped where a battery can supply them; the main panel needs at least a 225-amp busbar; and space must be reserved for a transfer switch within 3 feet of it. A home that installs a battery is exempt (2025 Energy Code). What a battery adds on top is in do I need a battery.
Owned, leased or PPA? Check this first
A builder can meet the requirement in different ways, and they are not worth the same to you.
If the panels are owned — bought by the builder and included in your price and mortgage — you own the system and its output. If they are leased or on a power-purchase agreement, a third party owns them and you pay a monthly fee or a price per kWh, often with an annual escalator, and the agreement has to be transferred or bought out when you sell. In LADWP territory a PPA does not qualify for net metering, because LADWP prohibits the sale of energy by anyone other than LADWP; a lease can qualify (LADWP net metering). There is no federal credit to claim on a home bought in 2026: expenditures after December 31, 2025 do not qualify for the Residential Clean Energy Credit (IRS; what ended).
What the panels are worth depends on the utility
The same new roof earns different money in SCE and LADWP territory.
A new home in SCE territory goes on the Net Billing Tariff: solar used in the house saves the retail price, but a midday export earns a 2026 system about 6¢ in summer and 3¢ in winter (plus a 1.6¢ bonus), while power from 4 to 9 p.m. on TOU-D-PRIME costs 61¢ on summer weekdays (SCE). That is why the battery-ready wiring matters there. In LADWP territory exports net against purchases kWh for kWh at the retail price over each billing period, so a solar-only system keeps most of its value (LADWP); see NEM 3.0 explained.
Built in, but still needs permission to operate
On a new home the solar system is part of the Title 24 energy compliance documents for the house, which record the PV size used to show compliance, and the builder’s team permits and installs it with the rest of the work. Before it runs connected to the grid, the utility still has to grant permission to operate. Adding panels later is an ordinary solar project; in the City of Los Angeles see solar permits and LADBS.
What a new-home buyer should check
Ownership
Owned and in the price, or leased? Ask for the contract, any escalator and the transfer terms.
Size against your use
The code minimum for a 2,000-square-foot Valley home is about 2.6 kW. If you will add an EV or a pool, ask about upsizing before the roof is finished.
Equipment and warranties
Get the panel and inverter models and the written warranties; see solar warranties explained.
Battery or battery-ready
Is a battery included, or only the wiring for one? On SCE it changes the system’s value.
Interconnection
Confirm permission to operate is granted and which tariff the system is on.
ADU on the lot?
Accessory dwelling units follow their own rules; see solar for ADUs in Los Angeles.
Where to go next
Cali Energy is a licensed Los Angeles solar, battery and electrical contractor (CSLB #1032379). Send us the Title 24 documents and the solar contract for a second opinion on an included system, or to price upsizing it. Call +1-323-844-7777 or get a new-build solar review.
Frequently asked
Are solar panels required on new homes in California?
Yes, for nearly all of them. The Energy Code prescribes a solar PV system for newly constructed buildings: under the 2019 code for permit applications from January 1, 2020, and under the 2025 code from January 1, 2026. The exceptions cover very small or shaded roofs, very small calculated systems, snow loads and some older planning approvals.
How big does the solar system on a new house have to be?
The smaller of two numbers: conditioned floor area × A ÷ 1,000 + dwelling units × B, with A and B by climate zone, or the sunny roof area times 18 watts per square foot on a sloped roof (14 on a low-sloped one). For a 2,000-square-foot home that is about 2.6 kW in climate zone 9, which covers most of the San Fernando Valley, and 2.4–2.7 kW elsewhere around Los Angeles.
Do new homes in California need a battery?
Not a single-family home. With electric service over 125 amps it must be battery-ready instead — backup circuits grouped for a future battery, a 225-amp main panel and space for a transfer switch — unless a battery is installed. A qualifying battery of at least 7.5 kWh lets the required PV size be cut by 25%.
Is the solar on a new-construction home owned or leased?
It depends on the builder. An owned system is in your price and mortgage; a lease or PPA belongs to a third party and you pay for it monthly, often with an escalator. In LADWP territory a lease can qualify for net metering but a PPA cannot. Ask for the contract before closing.
Can I get the 30% federal tax credit on a new-build solar system?
No. Expenditures after December 31, 2025 do not qualify for the Residential Clean Energy Credit, so a system bought with a home in 2026 earns no federal credit. This is general information, not tax advice.
Is the code-required system enough for my household?
It may cover only part of your use. A 2.6 kW system in Northridge produces about 4,400 kWh a year, while an average California home used about 6,000 in 2024, and an EV adds more. Upsizing while the house is being built is usually simpler than adding panels later.
Related reading
Sources & methodology
Figures on this page come from the primary sources below and, where noted, from Cali Energy calculations using the stated assumptions. Rates, incentives, and program terms change; each was verified October 5, 2026.
- California Energy Commission — 2025 Building Energy Efficiency Standards (CEC-400-2025-010-F): §150.0(s), §150.1(c)14, Table 150.1-C, §170.2(f)
- CEC — 2025 Building Energy Efficiency Standards (applies to permit applications from January 1, 2026)
- CEC — 2019 Building Energy Efficiency Standards (permit applications from January 1, 2020)
- CEC — Energy Code Support Center: solar PV, solar-ready, BESS and BESS-ready
- CEC — Building climate zones by ZIP code
- NREL PVWatts — production, Northridge, 20° south roof
- SCE — Solar Billing Plan (average Energy Export Credit values for 2026 systems)
- LADWP — Service Rider NEM, Net Energy Metering
- IRS — Residential Clean Energy Credit
Buying or building a new California home?
Send us the solar contract and Title 24 documents and we’ll review the included system — size, ownership, equipment and warranties — or price an upgrade. Estimates, not guarantees.
Get a free estimatePrepared by Cali Energy, October 5, 2026. This article is for general educational purposes only and is not legal, tax, financial, engineering, or utility advice. Rates, incentives, codes, permit requirements, equipment specifications, prices, and program terms may change; figures and timelines are estimates, not guarantees. Confirm current requirements with the applicable utility, AHJ, program administrator, manufacturer, or a licensed professional. See our Content Disclaimer. Cali Energy · 19201 Parthenia St, Unit E, Northridge, CA 91324 · CSLB #1032379 (B, C-10, C-39)