Solar & Renewables Under the 2026 California Building Code

Starting January 1, 2026, the 2025 California Energy Code (Title 24, Part 6), the energy portion of the broader California Building Standards Code, will take effect. These new rules further raise the bar on how buildings integrate solar PV, battery storage, and electric-ready infrastructure.

For solar designers, renewable energy developers, architects, and contractors, this is not a marginal update, it’s a shift in what normal Title 24 compliance looks like.

Below is a breakdown of what’s changing, what stays, and how to get ready.

Overview: California Building Code, Title 24 & CALGreen

The California Building Standards Code (Title 24) is the umbrella that contains the California Energy Code, CALGreen (Title 24, Part 11), and the building code itself.

The California Green Building Code (CALGreen) governs water efficiency, site development, indoor air quality, and other sustainability measures. While CALGreen intersects with energy requirements, most solar, solar-ready, battery-ready, and electric-ready mandates live in Title 24, Part 6 (Energy Code). When people reference the “California building code 2025,” they usually mean the 2025 updates to Title 24 energy standards, which take effect January 2026.

The energy code updates every three years, this cycle replaces the 2022 code.

Thus, when we talk about changes, we’re largely referring to the 2025 California Energy Code (Title 24 Part 6) and its impacts on solar design, storage readiness, electrification, and building planning.

Major Changes in 2025 (Effective 2026) Affecting Solar & Renewables in California Building Code

Here’s what changes compared to the 2022 cycle, focusing on solar PV, battery energy storage systems (BESS), solar-ready, battery-ready, and electric-ready requirements.

Single-Family & Detached Dwellings

• New homes must install solar PV or meet solar-ready requirements.

• Homes without immediate batteries must include battery-ready infrastructure (conduit, wiring, reserved space).

• A 200-amp main service panel is required, with labeled breaker space reserved “For Future Solar Electric.”

• Solar roof zones must meet area, shading, and azimuth rules; conduit routes must be reserved.

• The previous HERS-based metric is shifting toward an ECC (Energy Compliance) framework.

Multifamily & High-Rise Multifamily

• Distinguishes between dwelling units and common areas.

• Solar-ready and battery-ready requirements increase for shared infrastructure.

• Many buildings that previously only needed solar-ready features will now require more robust PV/BESS installations.

Nonresidential / Commercial / Assembly / Institutional

This is where the largest increases in Title 24 solar and battery requirements occur.

• Mandatory PV + BESS for most new nonresidential buildings.

• BESS energy and power capacity tied to PV size via Title 24 equations (140.10-B, 140.10-C).

• PV sizing keeps the CFA method and SARA (Solar Access Roof Area) method.

• New exceptions align with CALGreen requirements.

• More building types now fall under solar+BESS mandates (assembly, worship, labs, etc.).

• Updated calculation assumptions for both solar and storage capacity.

Electrification & All-Electric Baselines

The 2025 California Energy Code strongly encourages all-electric buildings.

• Heat pumps become baseline for mechanical systems.

• Ventilation and commissioning requirements tighten.

• Mandatory electric-ready infrastructure expands (conduit, wiring, panel space).

• Fossil fuel systems become less favorable under the new baseline.

Other Intersections & Local Reach Codes

• EV-charging readiness remains strong in multifamily and nonresidential.

• Some jurisdictions may adopt more stringent local reach codes.

• More documentation is required: energy models, BESS sizing, compliance forms, etc.

Why These Changes Are Being Made in the California Building Code

Decarbonization & Climate Goals

Supports California’s emissions targets using the Title 24 Energy Code as a driver.

Grid Resilience & Load Flexibility

Battery storage improves stability and demand shifting.

Technology Maturation

PV and BESS costs have dropped, increasing feasibility.

Policy Alignment

Ensures cohesion with statewide energy and incentive programs.

Electrification Push

Encourages transition away from natural gas.

How Solar / Renewable Stakeholders Are Affected because of the California Building Code

Design & Engineering Complexity

• Earlier and more holistic energy modeling.

• Structural design must accommodate PV loads.

• Electrical layouts must plan for solar-ready and battery-ready wiring.

• PV sizing pathways (CFA vs SARA) require strategic evaluation.

• Higher documentation burdens for Title 24 compliance.

Cost, Budget & Contracting

• Increased upfront solar/BESS costs.

• Need to include PV/BESS in early project scope.

• More supply chain coordination.

Risk & Permitting

• High risk of noncompliance if solar/BESS readiness is missed.

• Plan review requires proof of battery calculations and compliance forms.

Competitive Opportunities

• Firms mastering the new California Energy Code (Title 24) have a strong market advantage.

Supply Chain & Workforce

• Increased demand for skilled solar/BESS installers and engineers.

• Stronger commissioning and QA requirements.

How to Prepare: Checklist for Solar / Renewable Stakeholders

Monitor the final adopted 2025 Energy Code + local reach codes

• Ensures you track last-minute revisions and jurisdictional differences.

Update internal design standards

• Add solar roof zones, BESS space, conduit routes, electrical assumptions, panel space.

Begin early energy modeling using 2025 baselines

• Clarifies tradeoffs and compliance pathways.

Train your team on new PV/BESS/electric-ready requirements

• Avoids design errors and misalignment.

Audit vendor and supply chain capacity

• BESS, PV modules, conduit, and inverters may experience longer lead times.

Engage early with local plan check offices

• Identify how they interpret the new Title 24 solar and battery rules.

Run internal mock compliance checks

• Stress-tests your workflows.

Budget for additional solar/BESS/structural/electrical costs

• Reduces change order risk.

Strengthen coordination between architecture, structural, electrical, and solar teams

• Prevents costly clashes.

Prepare documentation templates (energy models, battery sizing worksheets, exceptions)

• Streamlines submittals.

Monitor reach codes beyond the statewide Title 24 baseline

• Some may require even more solar/storage capacity.

Develop strong QA/commissioning protocols

• Ensures PV + BESS systems pass inspection.

Conclusion on California Building Code

The 2026 California Building Code (2025 Energy Code) ushers in a future where buildings are solar-ready, battery-ready, electric-ready, and geared toward all-electric design from day one.

For renewable energy professionals, now is the time to:

• Update internal processes

• Strengthen coordination

• Educate teams

• Align supply chains

• Treat solar + storage as baseline Title 24 requirements

Solar Panels on Ocean View Home