Planning an ADU or a home addition in Solvang? Title 24 can shape your budget, schedule, and specs more than you think. A few early decisions determine whether you must add solar, upgrade your panel, or book special inspections. Here is a clear, local guide so you can plan with confidence.
What Solvang enforces
Solvang uses California’s 2022 Building Energy Efficiency Standards, known as Title 24, Part 6. The current edition took effect statewide on January 1, 2023, and the edition that applies to your project is set by the date you submit your permit application. The next cycle begins January 1, 2026. You can review the state overview for context in the 2022 standards summary from the California Energy Commission. See the CEC overview.
For local submittal steps and forms, start with the City of Solvang’s Building Permit page. Visit Solvang’s permit page.
ADUs: what applies
Detached ADUs
If you build a new, detached ADU from the ground up, it is generally treated like new home construction. That means the 2022 mandatory measures, whole‑building compliance, and often rooftop solar apply. Electric‑ready and energy storage system ready provisions also apply when you install gas appliances. For definitions and exceptions, review the state’s ADU guidance. Read the CEC ADU guidance.
Key point: A new, detached ADU typically triggers the solar requirement unless a specific exception fits your site or size.
Attached or conversion ADUs
If you convert existing space, or add an attached ADU to your home, the project usually falls under the additions and alterations rules. In most cases, the rooftop solar mandate does not apply, although the new work must meet current insulation, window, lighting, and equipment rules. See Section 150.2 summaries for additions.
Good news: Conversions and most attached ADUs usually avoid the new‑home solar requirement.
Additions: size matters
Additions follow Section 150.2. A few thresholds can change what you need:
- Additions of 1,000 square feet or less are exempt from the whole‑building mechanical ventilation airflow requirement, though other ventilation and efficiency rules still apply.
- Solar is generally not required for additions.
- Prescriptive envelope rules apply to the new portion, with some flexibility where you are not altering existing assemblies.
You can review these rules in the state’s addition and alteration summaries. Explore the additions rules.
Two ways to comply
Prescriptive path
The prescriptive path is a fixed checklist for envelope, windows, HVAC, water heating, and lighting. If you follow it item by item, you pass. It is simple, but it can force costlier upgrades in some projects.
Performance path
The performance path uses energy modeling to balance trade‑offs. For example, better windows or a more efficient water heater can offset other measures. This route often finds a lower total cost to comply, especially for ADUs and larger additions. See the CEC’s performance manual for how the modeling works. Review the performance manual.
What you cannot trade
Some items are mandatory under Section 150.0 no matter which path you choose. These include basic ventilation, lighting efficacy, certain envelope minimums, and specific field verifications when triggered. You can scan the mandatory list here. Check mandatory measures.
Budget drivers to watch
- Solar and roof conditions. New detached ADUs often need PV sized per the 2022 rules, limited by available solar roof area. Shade, roof layout, and interconnection can affect cost and timing. Learn how PV sizing works.
- Electric‑ready and battery‑ready provisions. New construction requires dedicated circuits, reserved panel spaces, and space for a heat pump water heater when gas is installed. Plan these early to avoid change orders. See 2022 electric‑ready guidance.
- HERS verifications. Duct sealing, refrigerant charge checks, insulation quality inspections, and other tests may require a third‑party HERS rater. Book early and budget for site visits. Review HERS requirements.
- Envelope upgrades. Higher R‑values, continuous insulation, and better windows can add cost, but they may reduce other requirements if you use the performance path.
Plan your sequence
Classify your scope. Decide if your project is a new, detached ADU or an attached conversion or addition. This sets whether solar and electric‑ready rules apply. Use the CEC ADU guidance.
Run early energy modeling. Ask your designer or energy consultant to compare prescriptive and performance packages before you lock finishes and systems. See the performance manual.
Coordinate electrical and solar. If PV or electric‑ready items apply, include panel sizing, reserved breaker spaces, and conduit routes in your plans. Review 2022 guidance.
Schedule HERS at the right stages. Plan for inspections at rough insulation for QII, at HVAC startup for refrigerant charge or duct tests, and at final for any remaining verifications. HERS guide and timing.
Align with Solvang submittals. Confirm forms and checklists before you apply so the edition and documents match what the City expects. Start your submittal here.
When you want to align this work with a sale, rental strategy, or long‑term value, you deserve seasoned guidance and a vetted local team. If you are considering an ADU or addition in the Santa Ynez Valley, connect with Laura Drammer to talk timing, budgets, and the vendors who can help you deliver a smooth build.
FAQs
Will my new ADU require solar?
- If it is a newly constructed, detached ADU, solar usually applies unless a listed exception fits your site or size. Conversions and most additions do not require solar. See ADU guidance.
If I add 400 square feet, do I have to upgrade my whole house?
- No. Additions follow Section 150.2. The new work must meet current rules, but many smaller additions are exempt from whole‑building ventilation, and solar is generally not required. Review additions rules.
Do electric‑ready and battery‑ready rules force me to install a battery now?
- No. They require wiring, panel space, and similar provisions so future upgrades are easier. Installation of new electric equipment or batteries is not required in most cases. Read 2022 guidance.
What inspections or tests should I budget for?
- If your project triggers them, HERS tests can include duct leakage, insulation quality, ventilation, and refrigerant charge checks. Plan for rater fees and scheduling. See HERS requirements.
Can Solvang add local rules that change this?
- Cities can adopt stricter “reach codes.” Check Solvang’s current requirements at submittal to confirm what applies to your project. Start with the City’s permit page.
