California’s Title 24 Solar Requirements Explained: A Guide for Multifamily Real Estate Developers

What is Title 24, Part 6?

California’s Title 24 Building Standards Code establishes the rules governing how buildings are designed and constructed across the state. Part 6 (also known as the California Energy Code) covers the energy-efficiency requirements for new and existing residential, multifamily, and commercial buildings. 

The current edition, the 2025 Energy Code, took effect January 1, 2026, and continues California’s push for building decarbonization through deeper electrification, encouraging more efficient heat pump technology, electric-ready infrastructure, stronger ventilation standards, and expanded requirements for solar and battery storage. The California Energy Commission (CEC) projects that the 2025 Energy Code will save $4.8B in energy costs and reduce GHG by about 4 million metric tons over its lifetime.

Does My Project Need to Comply with Title 24?

Title 24 applies to newly constructed buildings, additions, alterations, and accessory dwelling units (ADUs). The solar and storage mandates discussed in this guide, however, apply specifically to new construction. Projects that submitted complete permit applications after January 1, 2026 follow the 2025 code. 

Multifamily projects are governed by Section 170, and the rules are split out by building height:

Some projects qualify for limited exemptions, particularly where roof constraints or utility program limitations exist (e.g. if a multi-tenant project lacks access to virtual net metering (VNEM) or a community solar option). But, even when a building does qualify for exemptions, it still must meet “solar-ready” requirements that reserve space and pathways for future solar installation.

How Much Solar Is Required?

Under the CEC’s 2025 Energy Code, the required solar size depends on the building type and compliance path. For multifamily projects, the perspective PV size is determined by comparing the Conditioned Floor Area (CFA) and Solar Access Roof Area (SARA) method. 

The CFA Method is based on multiplying the building’s conditioned floor area by the capacity factor for its building type and climate zone (Table 140.10A). On the other hand, the SARA Method sizes the PV based on the usable roof area capable of supporting solar, including carports and all other newly constructed structures and multiplies it by 18 W/ft2 for steep-slooped roofs and 14 W/ft2 for low-slope roofs. (Section 170.2 (f)-(g)) You may use whichever compliant method produces the smaller system. 

Alternatively, the performance method uses CEC-approved software to model the building against the Energy Code baseline.

What About Battery Storage? Is it Required? 

For most new nonresidential buildings and high-rise multifamily developments, a battery energy storage system (BESS) is required alongside solar. Low-rise multifamily projects, on the other hand, are treated differently. While battery storage is not mandatory, you can choose to install a qualifying battery (see Joint Appendix 12) and reduce the required solar system size by 25%. 

The storage mandate improves grid flexibility. With solar generation often highest during the middle of the day and electricity demand peaking in the evening, batteries allow buildings to capture surplus solar energy and discharge it when it is most expensive.

What Are the Compliance and Documentation Requirements? 

Developers should be prepared to show: compliance pathway (either the prescriptive path or a performance path) and building type. These compliance documents are to be submitted to the local building department (the Authority Having Jurisdiction).  

• Pathway. There are two compliance pathways: a prescriptive path, which requires each component to meet set minimum requirements, and a performance path, which uses approved software to demonstrate that the whole building meets the Energy Code baseline. 

• Forms By Building Type. The code-specific forms vary depending on the type of building, with low-rise projects generally using CF forms and high-rise multifamily / commercial projects using NRCC forms. 

The certificates, regardless of path, must match the permitted plans, and a project cannot reach the permit final until they’re complete and consistent with what was actually built. 

What Does Title 24 Mean for Multifamily and Commercial Developers?

For multifamily and commercial property developers, Title 24 makes solar and battery storage a standard part of new construction. Rather than treating these as optional amenities, developers must now incorporate it into project design, budgeting, and permitting from the earliest stages. 

While these requirements increase upfront project costs, a solar-plus-storage system can also become an income-producing asset. Through programs like California’s Virtual Net Energy Metering (VNEM), property owners can allocate a portion of the solar value to tenants, while retaining a share of that value. 

However, once the project is live, someone has to allocate solar production, bill tenants, collect payments, and handle ongoing support.

How Fram Can Help

Fram helps bridge that gap between compliance and operations. Our platform provides the financial and operational infrastructure needed to manage solar and storage assets post-installation, automating value allocation, tenant billing, payment collection, and customer support end-to-end. 

Whether you’re planning a new multifamily development, commercial project, or solar installation, Fram can help you maximize the value of your investment while simplifying the operations.