What is Title 24?
Title 24 of the California Code of Regulations is the statewide building standards code governing how buildings are designed, constructed, and upgraded. It applies to nearly all new construction, major renovations, and many system replacements across California.
The code establishes minimum standards for structural safety, fire protection, energy efficiency, water conservation, and environmental performance. It also plays a central role in California’s climate strategy by reducing building energy consumption and supporting electrification, renewable energy, and grid resilience.
As buildings increasingly integrate technologies such as solar photovoltaic systems and battery energy storage systems (BESS), Title 24 continues to evolve to address how these systems are designed, modeled, and integrated into building performance.
Overview of Title 24 and Its Role in California Building Regulations
Title 24 is part of the California Code of Regulations and establishes statewide building standards for safety, efficiency, and sustainability. First adopted in 1978, Title 24 made California one of the earliest U.S. states to mandate energy efficiency through law.
Over time, the code has expanded to address a broad range of priorities, including structural integrity, fire safety, mechanical systems, and water efficiency. Today, Title 24 is organized into multiple parts, each covering a specific area of building design, performance, or safety.
Key areas include:
- Structural and seismic safety
- Electrical and mechanical systems
- Plumbing and water use
- Energy efficiency
- Green building practices
By requiring compliance at every phase of construction, Title 24 helps standardize sustainable and safe building practices statewide.
Key Parts of Title 24
Title 24 is divided into 12 active parts, each addressing a specific area of building design, safety, performance, or sustainability. Together, they form one of the most comprehensive building standards frameworks in the United States.
| Sections of Title 24 | Description |
|---|---|
| Part 1: Administrative Code | Outlines the administrative procedures for adopting and enforcing building standards. It includes definitions, agency responsibilities, and processes for submitting amendments or alternative materials and methods. |
| Parts 2 and 2.5: Building and Residential Codes | Set the structural and safety standards for most building types. Part 2 (CBC) applies to all structures and includes seismic, fire, and accessibility requirements. Part 2.5 applies to low-rise residential buildings and is based on the IRC. |
| Part 3: Electrical Code | Governs electrical system design and installation to ensure safety, reliability, and energy compliance. Includes provisions for PV systems, battery storage, and EV infrastructure. |
| Part 4: Mechanical Code | Details standards for HVAC, ventilation, and exhaust systems. Supports thermal comfort and indoor air quality. |
| Part 5: Plumbing Code | Addresses plumbing systems and water conservation, including piping, fixture performance, graywater systems, and drought-specific measures. |
| Part 6: Energy Code | Focuses on energy efficiency in construction and alterations. Includes requirements for insulation, lighting, HVAC, and renewable energy integration. |
| Part 7: California Wildland-Urban Interface Code | Establishes construction standards for buildings in wildfire-prone areas. Includes requirements for ignition-resistant materials, ember-resistant vents, and other measures that reduce wildfire ignition risk. |
| Part 8: Historical Building Code | Provides alternative compliance for historic building reuse, balancing preservation with safety and accessibility. |
| Part 9: Fire Code | Covers fire prevention and emergency planning. Addresses alarms, sprinklers, hazardous materials, and wildfire zone safety. |
| Part 10: Existing Building Code | Applies to repair, alteration, and change of occupancy. Enables safe upgrades without full reconstruction. |
| Part 11: CALGreen (Green Building Standards Code) | Sets mandatory and voluntary green standards including materials, landscaping, waste reduction, and air quality. |
| Part 12: Referenced Standards Code | Compiles technical standards and testing protocols used in other parts of Title 24 for consistency and alignment with national codes. |
Title 24 Part 6: Energy Code Deep Dive
Among all sections, Part 6, the Energy Code, is the most frequently referenced and has the greatest impact on building energy use and operating costs.
Most solar photovoltaic and battery storage provisions originate in Part 6 (Energy Code) and Part 11 (CALGreen). These sections establish requirements for renewable readiness, electrification, and high-performance building systems.
Compliance Pathways
Part 6 allows for three main approaches:
- Mandatory Measures: Baseline requirements that apply to all projects.
- Prescriptive Approach: Follows a checklist of approved efficiency features.
- Performance Approach: Uses energy modeling software to demonstrate that the proposed design performs as well as or better than a baseline standard.
To verify compliance with Part 6, project teams must use approved software tools such as CBECC-Res for residential buildings and CBECC-Com for commercial projects. These tools evaluate how the envelope, lighting, HVAC, and renewable systems interact to meet or exceed baseline energy performance.
As California advances its goals for grid decarbonization and resilience, Part 6 continues to evolve. Battery storage, solar readiness, and all-electric system integration are essential for code-compliant, future-ready buildings.
Key Requirements
Projects subject to Part 6 must meet performance standards across several core building systems:
- Envelope insulation and air sealing: Buildings must include adequate insulation in walls, roofs, and floors along with properly sealed openings to prevent air leakage. These measures reduce heating and cooling loads and support efficient HVAC operation.
- High-efficiency lighting and controls: New construction must use high-efficacy lighting such as LEDs along with automated controls including occupancy sensors, scheduling, and daylight-responsive dimming.
- HVAC and ventilation performance: Heating, cooling, and ventilation systems must meet strict efficiency criteria, including proper equipment sizing, high-efficiency ratings, duct sealing, and adequate ventilation for indoor air quality.
- Solar photovoltaic readiness: Most new low-rise residential buildings, and many commercial and multifamily structures, must install rooftop solar PV or be designed to support future installation through reserved roof space, conduit pathways, and panel capacity.
- Battery storage system readiness: Many projects now allocate physical space, conduit routing, and electrical capacity for future battery energy storage systems. In some cases, particularly in nonresidential or high-density residential applications, BESS installation may be required or used under performance-based compliance paths. Battery systems store excess solar energy, reduce peak demand, provide backup power, and enable demand response.
To address fire safety and thermal management challenges associated with lithium-ion storage, advanced BESS technologies such as EticaAG’s immersion-cooled systems provide enhanced safety and reliability in building-integrated energy storage deployments.
Compliance and Enforcement
Compliance with Title 24 is managed at the local level, typically by city or county building departments.
Responsibilities Include:
- Certified code officials are responsible for conducting plan checks to ensure that building designs comply with Title 24 requirements.
- Local authorities perform site inspections during and after construction to verify proper implementation of code-compliant systems.
- Project teams must submit all required documentation, including Certificates of Compliance such as CF-1R and NRCC forms.
- Installation Verification forms, including CF-2R and NRCI documents, must be completed and submitted to confirm proper equipment installation.
- HERS (Home Energy Rating System) field verifications are often required to assess and validate energy performance in residential buildings.
Failure to comply can result in penalties, stop-work orders, and delays in project approval or occupancy. Early integration of compliance planning into project timelines is essential for success.
Battery Storage, Fire Safety, and the Role of Immersion Cooling
As California buildings move toward energy independence and electrification, battery energy storage systems are becoming integral to Title 24 compliance, especially under Part 6. These systems support on-site renewable energy generation, enable demand-side load management, and provide backup power during outages.
Why Battery Storage Matters Under Title 24
BESS technologies enhance building performance by enabling:
- Time-of-use load shifting and peak shaving
- Resilience during power disruptions
- Better alignment with distributed solar generation
- Reduced reliance on the grid during high-demand periods
- Participation in utility demand response programs, allowing buildings to discharge stored energy during grid stress events and support statewide reliability initiatives
These capabilities contribute directly to California’s energy efficiency and grid reliability targets.
Thermal Management and Safety Considerations
As energy storage adoption grows, so do concerns about thermal runaway and fire safety, particularly in large or densely populated installations. Conventional cooling systems may not provide sufficient protection in the event of a fault or elevated heat conditions.
This is where immersion technology offers an advanced and reliable solution.
The Role of Immersion Cooling Technology
Immersion cooling technology involves fully submerging battery cells in a non-conductive, non-toxic fluid that transfers heat directly away from the cells. This approach provides:
- Uniform thermal regulation across the battery pack
- Isolation of battery cells from oxygen to prevent ignition and flame propagation
- Improved safety margins for fire-prone environments
- Enhanced system performance and longevity
For commercial and critical infrastructure projects, EticaAG’s immersion-cooled BESS systems offer both compliance support and safety assurance. They enable builders to meet energy code requirements while reducing the risk of thermal events, especially in locations where rapid suppression access is limited.
As Title 24 evolves, systems that combine energy efficiency and fire-safe battery storage will become increasingly important.
Benefits and Challenges of Title 24
Title 24 is often viewed as a regulatory hurdle, but it also delivers significant economic, environmental, and operational benefits.
Benefits
- Reduced Operating Costs: Efficient systems and controls lower energy bills. When paired with solar and BESS, buildings can store excess energy, reduce peak demand charges, and improve load balancing.
- Improved Indoor Air Quality: Ventilation standards in mechanical and green building codes enhance occupant health and comfort, particularly in homes, schools, and commercial buildings.
- Environmental Impact: Buildings account for a large share of greenhouse gas emissions. Title 24 supports California’s climate targets by reducing energy consumption and lowering emissions through improved building performance.
- Property Value and Marketability: Energy-efficient and sustainable buildings are increasingly attractive to tenants, buyers, and investors. Compliance with Title 24 can improve long-term asset value and market competitiveness.
Challenges
- Cost and Complexity: High-performance systems, insulation, and controls can increase upfront costs, particularly for retrofit projects. Compliance may also require specialized modeling software and technical expertise.
- Retrofit Feasibility: Older buildings may face structural or spatial limitations that make full compliance difficult without significant upgrades.
Despite these challenges, state and utility incentives, including rebates and tax credits, can help offset costs and support broader adoption.
Key Changes in the 2025 Title 24 Update
The 2025 update to Title 24, adopted in July 2025 and effective January 1, 2026, advances the state’s goals for energy efficiency, electrification, and climate resilience. The updated standards strengthen building performance, expand electric-ready infrastructure, and introduce new wildfire-resilience requirements.
Key updates affecting residential and commercial building design include:
- Energy Efficiency: Lower U-factor requirements for windows and framed walls in single-family homes reduce heat loss and improve insulation. The update also introduces a new prescriptive pathway for cathedral ceilings to improve energy performance in complex roof assemblies.
- Heat Pump Systems: Mandatory ventilation requirements now apply to heat pump water heaters in all building types. The update also establishes new performance criteria for heat pump space heating systems to ensure proper sizing and improved thermostat control.
- Electrification and Grid Integration: Commercial kitchens must be electric-ready to support the transition away from gas appliances. Updated standards also expand solar PV and battery storage requirements for high-rise multifamily and selected nonresidential buildings.
- Indoor Air Quality: Ventilation requirements for multifamily dwellings are strengthened to improve occupant health and comfort.
These updates are expected to save $4.8 billion in energy costs and eliminate 4 million metric tons of greenhouse gas emissions, equivalent to the annual energy use of more than 500,000 homes.
Conclusion
Title 24 represents California’s commitment to resilient infrastructure, sustainable development, and energy independence. The standards are updated every three years to reflect advances in building technology, safety requirements, and energy policy.
For builders, designers, and energy professionals, understanding Title 24 is both a requirement and a competitive advantage. It shapes better projects, supports climate goals, and opens the door to high-performance technologies like battery storage and immersion cooling.
By aligning design and construction practices with the requirements and opportunities outlined in Title 24, stakeholders can deliver buildings that are not only compliant but also efficient, resilient, and future-ready.
