Do You Need Solar in California?

Solar PV Requirements in California: What You Need to Know

California leads the nation in clean energy standards—and nothing embodies that more than its Title 24 Building Energy Efficiency Standards. These rules ensure that all newly constructed buildings contribute to the state’s bold renewable energy goals. Here's what you need to know about the PV (photovoltaic) requirements under Title 24.

1. A Solar Mandate That Started a Revolution

Since January 1, 2020, California has required that most new residential buildings—including single-family homes and low-rise multifamily dwellings (up to three stories)—implement solar PV systems as part of the building design.

This isn't just a guideline—it’s enforceable code. Failing to include a compliant solar system can delay building permits and obstruct obtaining a Certificate of Occupancy.

2. How Much Solar is Required?

Title 24 sets a minimum PV system size using one of two approaches:

• SARA method: Calculates the system size that the building’s solar-compatible roof area (Solar Access Roof Area) can support.

• Equation-based method: Uses a formula considering conditioned floor area, dwelling unit count, and climate zone.

  
  

For example, Equation 150.1-C for single-family homes (and Equation 170.2-C for low-rise multifamily) lays out exactly how to determine the required kWdc capacity.

3. Exceptions: When Solar Isn't Mandatory

Title 24 acknowledges that not every building is ideal for solar. There are formal exceptions—situations where you can legally omit solar PV:

• When the calculated minimum PV size is under 1.8 kWdc.

• Insufficient or shaded roof area—e.g., SARA < 80 contiguous ft², or steep-slope roofs with northern orientations.

• Snow load concerns—if solar panels cannot meet ASCE 7-16 standards due to roof design.

• Pre-2020 approved projects—some older planning approvals come with conditions that allow exemption.

• Battery storage—installing a qualified battery system (7.5 kWh or greater) can reduce the PV requirement by up to 25%.

4. Broader Scope: Commercial & High-Rise Projects

Starting in 2023, Title 24 expanded solar mandates to non-residential and high-rise residential buildings, requiring not only PV installations but in many cases also battery energy storage systems (BESS).

5. Why California Pushes Solar

California’s aggressive renewable energy goals—such as reaching 60% renewable electricity by 2030 and 100% by 2045—are central motivations behind Title 24's mandates. By incorporating solar into building construction, the state continues to lead in reducing carbon emissions and encouraging local clean energy adoption.

Summary Table

Project Type	Solar PV Required?	Notes
New residential (≤3 stories)	Yes, unless exempt	Must meet one of the exception conditions
New multifamily (≤3 stories)	Yes, same exceptions apply	Uses Eq. 170.2-C; similar PV exemptions as single-family
Commercial / High-rise ≥3 stories	Yes, PV + BESS often required	Battery storage may be mandatory per 2023 updates

Final Thoughts

California’s Title 24 is shaping the future of building design by embedding solar energy into code compliance. Whether you're a developer, architect, or homeowner, understanding how PV requirements and exceptions work is essential to smooth permitting and sustainable project outcomes.