ADU Solar Requirements in California: Title 24 Compliance

California’s housing shortage has fueled a surge in Accessory Dwelling Units (ADUs), giving homeowners a smart way to add rental income, create multigenerational living spaces, or boost property value. But with new construction also comes new regulations. Under California’s Title 24 energy code, many ADUs built in 2025 and beyond must include solar panel systems to meet the state’s clean energy and efficiency standards.

For homeowners in Southern California, understanding these solar requirements is essential before starting your ADU project. This guide breaks down when solar panels are required, possible exemptions, how much solar you’ll need, and how US Power can help ensure your ADU is fully compliant—without unnecessary costs.

What Is Title 24 and Why Does It Matter?

Title 24 is California’s Building Energy Efficiency Standards, updated every three years to push the state closer to its renewable energy and carbon reduction goals. The 2022 update (in effect for 2023–2025 projects) requires many new residential builds, including certain ADUs, to integrate solar energy systems.

For homeowners, that means if you’re planning to build an ADU in 2025, your project may need solar panels to meet code before it can be approved and connected to the grid.

Do All ADUs Require Solar in 2025?

Not every ADU must install solar panels—but many do. Here’s the breakdown:

• Attached ADUs (part of a new single-family home) → Solar is required as part of the whole home’s Title 24 compliance.
• Detached ADUs built from the ground up → Likely require solar, depending on square footage, electrical load, and climate zone.
• Converted ADUs (garage, basement, or existing structure) → Typically exempt from solar since the primary home already accounts for energy compliance.

Local permitting offices may also apply unique rules, so it’s best to confirm requirements before construction begins.

How Much Solar Do You Need for an ADU?

The exact system size depends on factors like:

• The ADU’s square footage and expected energy demand.
• Appliance choices (electric vs. gas).
• Roof orientation and shading.
• Whether the ADU shares energy systems with the primary home.

In many cases, a smaller solar array—sometimes just a few panels—is enough to meet Title 24 for an ADU.

Benefits of Adding Solar to Your ADU

Even beyond compliance, adding solar to your ADU offers long-term advantages:

• Lower Energy Bills – Offset utility costs for tenants or family members.
• Higher Property Value – Homes with solar and ADUs command higher resale prices.
• Rental Market Appeal – Energy-efficient ADUs are more attractive to renters.
• Future-Proofing – Stay ahead of California’s stricter energy mandates.

Why Work with US Power for ADU Solar?

Building an ADU in Southern California already involves navigating permits, inspections, and design requirements. The last thing you want is delays from Title 24 noncompliance.

That’s where US Power makes the difference:

• Exclusive Qcells Partnership – Get factory-direct, American-made panels designed for efficiency and durability.
• Local Expertise – Our team knows California building codes inside out, ensuring your ADU project passes inspection the first time.
• Tailored Solar Solutions – We design right-sized systems so you only pay for the solar you actually need.
• End-to-End Service – From consultation to installation, we handle everything—so you can focus on building your ADU.

US Power is Here For You

As California continues to push toward a clean energy future, Title 24 compliance is non-negotiable for many new ADUs. While not every project requires solar, most homeowners will benefit from installing a system that not only meets state requirements but also cuts energy bills and boosts property value.

With US Power’s local expertise and exclusive Qcells partnership, you can rest easy knowing your ADU solar installation is fully compliant, cost-effective, and built to last.

Ready to make your ADU Title 24-compliant with solar? Contact US Power today for a free consultation and factory-direct solar pricing.