Title 24

Quick Facts

Title 24 Structure

Part 6, Energy Code

• Building envelope, HVAC, lighting, water heating, plug loads.
• Solar PV mandate (since 2020).
• Battery storage mandate (since 2023 for non-res / high-rise res).

Part 11, CALGreen

• Sustainable construction (water, materials, indoor air).
• Separate from Part 6 but often referenced together.

Solar PV Mandate Details

Coverage

• Single-family homes (new).
• Multifamily up to 3 stories.
• New ADUs > 700 sf in some jurisdictions.

Exemptions

• Severely shaded sites (TSRF < 70%).
• Roof area insufficient (< 80 sf usable).
• Substantially oriented (N-facing roof only).
• Site solar resource < 70% of climate-zone reference.

Sizing

TDV calculation in CBECC. Typical results: 2-4 kW per dwelling. Larger for high-conditioning climates (Coastal: smaller; Inland Empire / Central Valley: larger).

Battery Storage Mandate (2023)

Coverage

• New non-residential (offices, retail).
• New high-rise residential (>3 stories).

Sizing

Tied to building Tier of demand. Typical: 10-25 kWh per 5,000 sf of building.

Compliance Paths

Prescriptive

Meet specific requirements per climate zone for envelope, HVAC, solar size. Easier for designers, less flexibility.

Performance

Demonstrate building total source energy ≤ a reference building’s source energy. More design flexibility.

Mixed-fuel reference vs. all-electric

2022 code favors all-electric construction; mixed-fuel buildings face stricter performance targets.

Solar-Ready & Battery-Ready

For homes not installing full solar (exempted), Title 24 requires “solar-ready”:

• Reserved roof area ≥ 250 sf with appropriate solar window.
• Conduit pathway from roof to electrical room.
• Service capacity for future expansion.

Battery-ready (2022 code):

• Dedicated 200 A subpanel or service compartment for future battery.
• Pre-wired EVSE outlet in garage.

Permitting Implications

• Title 24 Form CF-1R submitted as part of the solar permit design package alongside the permit application.
• Solar system size must match the CF-1R calculation.
• The reviewing AHJ checks both CF-1R and the actual SLD for consistency.
• Re-roof of existing homes may require solar evaluation in some jurisdictions.

Common Mistakes

1. Designing solar without aligning with Title 24 TDV calculation.
2. Skipping solar-ready provisions when claiming exemption.
3. Outdated CBECC software version (incompatible with code edition).
4. Missing battery-ready provisions in 2023+ non-residential projects.
5. Ignoring CALGreen separate requirements.

Best Practices

• Use latest CBECC version matching the AHJ’s adopted code edition.
• Coordinate solar design with the architect’s energy report.
• Document exemptions thoroughly when claiming.
• Pair Title 24 sizing with NEM 3.0 export economics and the federal ITC for max customer value.

Standards & Certifications

• California Code of Regulations, Title 24, Part 6.
• CBECC (California Building Energy Code Compliance) software.
• CALGreen (Title 24, Part 11).
• ASHRAE 90.1 (referenced for some provisions).

Related Reading

For a broader view of how Title 24 fits into California’s permitting process, our California AHJ Solar Permit Guide covers how the CF-1R energy report interacts with NEC 2020/CEC adoption and the requirements of the state’s busiest AHJs.

Once the Title 24 sizing and energy report are finalized, the next step is assembling the actual submission, see how to submit a solar permit package to an AHJ for the checklist of documents reviewers expect.

And for anyone weighing whether to pair a Title 24 battery-ready compartment with an actual battery install now rather than later, this comparison of lithium vs. lead-acid solar batteries is a useful primer on the chemistry trade-offs before committing to a system size.

Key Takeaways

• California Title 24 Part 6 mandates solar PV on new low-rise residential since 2020 and battery storage on new non-residential / high-rise residential since 2023.
• Solar sizing via TDV (Time-Dependent Valuation) calculation in CBECC.
• Exemptions exist for severely shaded, oriented, or roof-constrained sites.
• “Solar-ready” and “battery-ready” provisions apply to exempted properties.
• Compliance verified via Form CF-1R submitted with the building permit.

Disclosure: Heaven Green Energy is a Heaven Designs group company.