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Does your ADU need solar? Check Title 24 in seconds

California's Title 24 energy code requires solar PV on most new dwellings, sized by floor area and climate zone. Smaller ADUs often fall under the 1.8 kW exemption threshold and need no solar at all. Pick your climate zone and see where each ADU2Me package lands.

Select your project's California climate zone to see the Title 24 required solar PV size for each ADU2Me package (per 2022 Energy Code, Equation 7-1). Systems below 1.8 kW qualify for Exception 2 — no solar required.

* Estimated simulation only. The SIPs performance path reduction shown here is an approximation based on the envelope efficiency of SIPs construction — superior R-values, zero thermal bridging, and air infiltration up to 15× tighter than stick frame. Actual savings vary by site, design, climate, and HVAC system. The performance compliance path requires formal modeling in CBECC-Res software by a licensed California Title 24 energy consultant. Results must be certified and submitted with your building permit application. Contact ADU2Me to connect with a Title 24 consultant.

SIPs advantage: The numbers above use the prescriptive formula — floor area and climate zone only. Check Simulate SIPs performance path above to see an estimated reduction based on the SIPs envelope advantage. Actual results require certification by a licensed Title 24 energy consultant.

Based on California Title 24 (2022 Energy Code) Table 7-1 & Equation 7-1. Formula: kW = (conditioned sq ft × A) ÷ 1,000 + B. Exemption if < 1.8 kW (Exception 2) or roof solar access < 80 contiguous sq ft (Exception 1). Consult a licensed Title 24 energy consultant for your specific project and jurisdiction. SIPs performance estimate based on envelope efficiency advantages of structural insulated panel construction.

Why it matters

A smaller, tighter ADU can skip the solar line item

A required solar system adds real cost to a build. Our two under-750 sf models typically calculate below the exemption threshold in San Diego County, and the SIP envelope's performance can shrink the requirement on larger models when formally modeled by a Title 24 consultant.

See what fits on your lot → Ask about Title 24 consulting →