Owner/Builder ADU Guide: Title 24 2025 Energy Compliance in California

If you’re an owner/builder planning an Accessory Dwelling Unit (ADU) in California, Title 24 energy compliance is required — and the 2025 code cycle brings important changes you need to know before your project begins.

ADUs are treated as new construction under California’s Title 24, Part 6. That means full ECC (Energy Code Compliance) verification is required before your permit can close. Whether you’re converting a garage, building an attached addition, or constructing a free-standing unit, energy code compliance applies from day one.

Under the 2025 Building Energy Efficiency Standards, ADU projects typically require: a Certificate of Compliance (CF1R) prepared by an energy consultant, field verification by a certified ECC Rater for HVAC systems, insulation (QII), ventilation, and water heating, and all compliance documentation submitted to the CHEERS data registry before permit close.

Schedule a free consultation before your plans are finalized. Early design decisions — equipment type, insulation strategy, and duct location — directly affect what ECC testing will cost. Getting ADU energy compliance wrong can delay your final inspection significantly.

California Energy Code Compliance works with owner/builders throughout Los Angeles, Ventura, Santa Barbara, and San Luis Obispo Counties. We review your CF1R, identify what Title 24 2025 verifications are required, and coordinate all ECC testing so your ADU project closes on time. Call 805.813.1204.