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California's 2025 Energy Code Solar and Battery Rules for New Commercial Buildings, Explained

October 21, 2026 · Burge Energy · 8 min read

The 2025 Energy Code solar and battery storage requirements apply to new nonresidential buildings whose permit applications are filed on or after January 1, 2026. California first added prescriptive PV and battery rules for specific nonresidential building types in the 2022 code, which applied to permits filed on or after January 1, 2023. The 2025 cycle adds building types, raises several PV capacity factors and rewrites the battery sizing equations. For Orange County developers, architects and owners, these rules set a minimum system size that must be designed and documented at permit.

Key takeaways

  • New buildings are covered when at least 80 percent of total floor area falls into building types listed in Table 140.10-A.
  • The 2025 code adds events and exhibits, religious worship, and sports and recreation to the covered list (CEC Blueprint, Fall 2025).
  • Required PV is the smaller of a floor area calculation and a roof area cap of 18 W per sq ft (steep-sloped) or 14 W per sq ft (low-sloped) of solar access roof area (CEC).
  • Any building that must install PV must also install a battery unless a BESS exception applies.
  • PV and BESS rules do not apply to additions or alterations, but a first-time tenant improvement is treated as new construction (CEC).
  • Anaheim lists Climate Zone 8 and Laguna Niguel lists Climate Zone 6, and capacity factors change by zone.

Which buildings must include PV and battery storage

Section 140.10 of Title 24, Part 6 is titled Prescriptive Requirements for Photovoltaic and Battery Energy Storage Systems. It applies to newly constructed nonresidential buildings where at least 80 percent of total floor area, conditioned or not, serves building types listed in Table 140.10-A. Mixed-occupancy buildings are included, with PV sized for each building type and then summed (CEC Energy Code Support Center).

Table 140.10-A lists office, financial institution, unleased tenant space, medical office and clinic, retail, grocery, restaurant, hotel/motel, library, school and warehouse, plus the three new types below.

What changed from the 2022 code, per the CEC's What's New summary and the Fall 2025 Blueprint:

  • Three building types added: events and exhibits, religious worship, and sports and recreation.
  • Higher PV capacity factors for libraries in Climate Zones 2 to 16, and for hotel/motel, medical office and clinic, restaurant, retail and grocery in all zones.
  • Revised BESS Equations 140.10-B, -C and -D, and new BESS capacity factors for every building type.
  • An updated tenant space exception (Exception 5).

Multifamily PV and BESS rules sit in Section 170.2 with their own tables (CEC Blueprint, Summer 2025), so confirm early which section governs a mixed-use project.

How the 2025 Energy Code solar and battery storage requirements are sized

PV. Equation 140.10-A multiplies conditioned floor area by the Table 140.10-A capacity factor (W per sq ft) and divides by 1,000 to get kWdc. A second calculation multiplies solar access roof area (SARA) by 14 W per sq ft for low-sloped roofs or 18 W per sq ft for steep-sloped roofs. The required PV is the smaller result (2025 Compliance Manual, Ch. 9). SARA excludes roof area with less than 70 percent annual solar access (CEC), and it can include covered parking, carports and other new structures on the site (Blueprint, Fall 2025).

BESS. Equation 140.10-B sets minimum usable energy: floor area times the Table 140.10-B factor (Wh per sq ft), divided by 1,000 times the square root of the battery's round-trip efficiency. When the SARA cap controls PV size, Equation 140.10-C scales the battery down by the ratio of SARA-based PV to floor-area PV. Equation 140.10-D sets minimum power at usable kWh divided by 4 (2025 Compliance Manual, Ch. 9). Sizing uses rated usable capacity, not nameplate (CEC).

Example (not a design). Using the equations above and the Climate Zone 8 office factors in the table below, a 40,000 sq ft office needs 40,000 x 3.13 / 1,000 = 125.2 kWdc of PV if the roof cap is larger. With a 90 percent round-trip efficiency battery, usable energy is about 221.8 kWh and power about 55.4 kW.

Capacity factors for common Orange County climate zones

Building type PV factor CZ 6 (W/sq ft) PV factor CZ 8 (W/sq ft) BESS factor CZ 6 (Wh/sq ft) BESS factor CZ 8 (Wh/sq ft)
Office, financial institution, medical office/clinic 3.13 3.13 5.26 5.26
Retail, grocery 3.27 3.83 1.80 1.92
Restaurant 8.73 10.18 4.02 4.49
Hotel/motel 1.87 2.22 0.89 1.01
School 1.63 1.63 3.05 3.05
Warehouse 0.44 0.44 0.41 0.41
Events and exhibits 4.05 4.83 2.13 2.30
Religious worship 4.29 5.89 2.75 3.37
Sports and recreation 1.84 2.63 1.20 1.57

Values are from Energy Code Ace's 2025 Tables 140.10-A and 140.10-B. The CEC announced errata to the Table 140.10-B battery factors effective January 1, 2026. The Building Standards Commission's Information Bulletin 26-01 says those fixes cover retail, grocery and warehouse in Climate Zones 1 and 3, not Zones 6 or 8. Confirm against the current code text.

Exceptions that reduce or remove the requirement

PV exceptions in Section 140.10(a) (CEC):

  1. Total SARA is less than 3 percent of conditioned floor area.
  2. The required PV is under 4 kWdc.
  3. SARA has fewer than 80 contiguous sq ft.
  4. The enforcement agency finds the PV cannot meet ASCE 7-16 Chapter 7 snow loads.
  5. In multitenant buildings, tenant spaces of 2,000 sq ft or less with their own HVAC system and utility meter are excluded from the PV calculation, unless a qualifying community solar or virtual bill credit program applies.

BESS exceptions in Section 140.10(b) (CEC): no battery if installed PV is under 15 percent of the Equation 140.10-A capacity, or if required usable energy is under 10 kWh. Single-tenant buildings under 5,000 sq ft need no battery, and multitenant buildings size storage only from tenant spaces over 5,000 sq ft. The PV requirement still applies when a battery exception is used.

Climate Zone 1. Schools, offices, financial institutions, unleased tenant spaces, and medical office buildings and clinics in Climate Zone 1 do not require a battery (Blueprint, Fall 2025). The errata notice adds warehouses in that zone (Blueprint, Summer 2025). None of these exemptions apply in Climate Zones 6 or 8, where Table 140.10-B sets a battery factor for every building type.

Additions, alterations and tenant improvements

PV and BESS requirements do not apply to additions or alterations. Unconditioned buildings are also excluded, except unoccupied first-time tenant improvement spaces. A first-time tenant improvement counts as new construction, while a tenant improvement in a previously occupied space is an alteration (CEC).

Solar-ready rules under Section 110.10 are separate. They cover new nonresidential buildings of three habitable stories or fewer (other than Group I-2 and I-2.1) and hotel/motel buildings of ten or fewer, when PV is not otherwise required. They reach additions only when total roof area grows by more than 2,000 sq ft (CEC).

Compliance forms, signatures and utility interconnection

The prescriptive path uses the NRCC-SAB-E Certificate of Compliance for solar and battery. Solar-ready projects use NRCC-SRA-E (2025 Compliance Manual, Ch. 9). Each NRCC is signed by a documentation author and a responsible person who must be eligible under Division 3 of the Business and Professions Code, then submitted with the permit application (Compliance Manual, Ch. 2).

During construction, the installer completes the NRCI-SAB-E Certificate of Installation, comparing as-built PV and battery data to the permitted design; a shortfall requires a revised Certificate of Compliance. The installing contractor signs the NRCI (Compliance Manual, Ch. 2). Batteries must meet Joint Appendix JA12 and be CEC-certified; prescriptive systems need round-trip efficiency above 80 percent (CEC).

Under the performance path, a battery larger than the prescriptive requirement can offset a smaller PV system (CEC).

The Energy Code sets minimum size, not utility approval. The CEC notes the load-serving entity may impose its own interconnection requirements, and that on multibuilding sites the enforcement agency approves where PV is located and how it is allocated (Blueprint, Fall 2025).

What this means for your project

  • Confirm the climate zone by address. The CEC's climate zone tool maps physical location. A ZIP code can contain more than one zone, and local jurisdictions may assign one zone per ZIP.
  • Run the 80 percent test at schematic design. Occupancy mix decides whether Section 140.10 applies.
  • Measure SARA early. Rooftop equipment and shading can make the roof cap control.
  • Plan tenant layouts with the exceptions in mind. The 2,000 sq ft PV and 5,000 sq ft battery thresholds turn on tenant size, metering and HVAC.
  • Ask the utility about interconnection early, before equipment is locked in.
  • Assign signers for the NRCC (responsible person) and the NRCI (installer).

Code requirements depend on project specifics and local amendments. Confirm with your architect, engineer and the local building department before relying on anything here.

Frequently asked questions

Do new commercial buildings in California have to have solar panels?

Most do. A newly constructed nonresidential building must install PV when at least 80 percent of its floor area serves building types in Table 140.10-A, such as office, retail, school or warehouse, unless an exception applies. Exceptions include a required system under 4 kWdc or solar access roof area under 3 percent of floor area (CEC).

Is battery storage required for commercial buildings under Title 24?

Yes, when PV is required, a battery is also required unless an exception applies. Exceptions cover installed PV under 15 percent of the floor-area PV size, required storage under 10 kWh, and single-tenant buildings under 5,000 sq ft. The battery must meet Joint Appendix JA12 and be CEC-certified (CEC).

Does the solar requirement apply to tenant improvements or additions?

Not to additions or alterations. A tenant improvement in a previously occupied space is treated as an alteration and is exempt. A first-time tenant improvement in a never-occupied space is treated as new construction, so the 2025 PV and battery rules apply when its permit application is filed on or after January 1, 2026 (CEC).

What Title 24 climate zone is Orange County in?

It depends on the parcel. Anaheim lists Climate Zone 8 and Laguna Niguel lists Climate Zone 6 in their design criteria. Because a ZIP code can span more than one zone, the CEC offers an address-based climate zone tool. Capacity factors for PV and storage change with the zone.

When does the 2025 California Energy Code take effect?

Buildings whose permit applications are filed on or after January 1, 2026 must comply with the 2025 Energy Code (CEC). Applications filed before that date follow the 2022 code. Applications filed on or after January 1, 2026 must also use approved 2025 compliance software and forms (Blueprint). The CEC's August 17, 2026 list shows CBECC 2025.2.0 and 2025.2.1 approved for nonresidential projects (CEC).

How Burge can help

Burge Energy designs and builds commercial solar and battery storage alongside the structure, for new buildings and existing sites across Orange County and Southern California. Because Burge Energy is part of a general contractor building since 1977, roof structure, solar access, battery placement and electrical design are coordinated by one team from the first budget. Request an Energy Assessment, or see commercial solar and battery storage.

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