California's Title 24 standards require solar PV for most new low-rise residential statewide; whether it applies to a home addition project depends on scope.
Solar under Title 24
The 2020 standards introduced solar PV for most new low-rise residential; the 2022 standards expanded solar/battery provisions to more building types. For home addition work, applicability depends on whether new dwelling units or qualifying construction are involved. Title 24 is a statewide California energy code. Home Addition projects follow the same statewide standards; the exact requirements depend on your project's scope and address, which we model in CEC-approved compliance software.
Related: Home Addition Title 24 overview · pricing · Title 24 guide.