Design
Title 24
Title 24 is California's building energy-efficiency standard, part of the state building code. Every new ADU must include Title 24 compliance documentation — covering insulation, windows, HVAC, and often electrification — in its permit submittal. New detached units face the strictest requirements; garage conversions and JADUs that reuse existing structure have lighter ones.
Title 24 compliance is usually prepared by the designer and adds modest cost but is non-negotiable for plan check. Garage conversions and JADUs have lighter requirements than new detached construction.
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