ADU Solar Panel Requirements in Southern California

June 7, 2024
5 min read
Solar panels on top of an ADU in a backyard


TENCO SOLAR helps California residents understand the solar panel requirements for newly built ADUs under Title 24. In this blog, we cover:

  • What Title 24 is and what it means for California residents.
  • Whether solar panels are required for new construction ADUs.
  • Exemptions to solar requirements under Title 24.
  • Why residents should consider solar panel installation regardless of exemption status.

If you’re considering building an accessory dwelling unit (ADU) on your California property, you may have questions about the state’s new energy requirements. Under updated Title 24 building requirements, new construction ADUs may be required to have solar panels installed in some California jurisdictions.

Read on to find out what this new guidance entails and whether it applies to your ADU construction plans.

What Is Title 24?

Title 24 is a piece of California legislation that states that after January 1, 2020, all newly built, non-manufactured, detached ADUs need to install solar panels if the local jurisdiction enforces the prescriptive energy requirements in California’s state code.

According to these prescriptive requirements, any newly constructed, detached accessory dwelling units for which the permit application was submitted on or after January 1, 2020, must install solar panels.


Yes — newly constructed ADUs must have solar panels installed if they’re non-manufactured and detached from the main home. According to the California Energy Commission, the panels can either be installed onto the ADU or on the primary dwelling unit.

Some may interpret this to mean any shed, barn, outhouse, or home addition may be subject to solar panel installation requirements under Title 24. However, there are exemptions that may not require all California homeowners planning to build an ADU to install solar panels.

Exemptions To Solar Requirements Under Title 24

You might not have to install solar panels on your ADU or primary dwelling unit if your building plans fall under one of these exemption categories:

  • Manufactured unit: If the ADU you plan to build is a manufactured unit, these are subject to Title 25, not Title 24, and therefore may not be required to have solar panels installed.
  • Attached ADUs: An attached accessory dwelling unit is considered a home addition and doesn’t require residents to meet the prescriptive energy requirements in California’s state code.
  • Conversion ADUs: Converting an existing ADU — even if it’s detached — is also considered a type of home addition and therefore does not need to have solar panels installed.
  • Space size: You may be exempt from needing solar panels installed if you don’t have a large enough surface area (less than 80 contiguous square feet) with unshaded solar access.

While Title 24 offers statewide solar panel installation guidance for newly constructed ADUs, cities and counties may adopt different standards throughout the state. The PV system requirements also vary depending on your geographic location and climate zone. Always refer to your local guide to determine if your ADU building plans require you to budget for solar panel installation.

Why You Might Want Solar Panels Anyway

Having a government agency that requires you to install solar panels for any new building plans on your property might seem like overreach to some. But there are plenty of good reasons why homeowners may want to consider solar panel installation regardless of what the government has to say about it:

  • Energy savings: Installing solar panels can significantly reduce or eliminate your energy bills as you no longer need to rely on the power grid for electricity.
  • Tax credits: With federal, state, local, and Solar Renewable Energy Credits, the average homeowner can recoup the cost of their installation investment in 3.5 years.
  • Environmentally friendly: Solar panels allow you to access clean, pure energy from the sun, helping the environment as you reduce your carbon footprint.


Are you interested in reaping the benefits of solar energy for your ADU or primary dwelling unit?

At TENCO SOLAR, we help you harness the power of the sun to reduce your environmental footprint and trim your monthly utility bills. Our experts are always ready to answer your questions and help you identify the best system for your needs and comfort.

Contact us to request a free solar panel quote for your ADU or home.  (888) 507-6937

Have a Solar project in mind?

With over two decades of expertise in designing and installing solar systems for residential and commercial properties across California, TENCO SOLAR is the perfect partner for your upcoming solar project.