Title 24 Energy Compliance: What Bay Area Homeowners Need to Know

By Raven Vuong

If you're planning a remodel, addition, or new build in the Bay Area, understanding Title 24 energy compliance California is not optional — it's the law. Title 24, Part 6 of the California Code of Regulations sets the state's Building Energy Efficiency Standards, governing everything from insulation levels and window performance to HVAC systems and lighting. For Bay Area homeowners, these rules apply to nearly every permitted construction project, and failing to meet them can delay your permit, require costly rework, or halt your project entirely.

The good news: working with an experienced local contractor who knows these standards inside and out makes compliance straightforward. Whether you're building a home addition, converting a garage into living space, or constructing a new ADU, knowing what Title 24 requires before you break ground saves time and money. This guide covers what you need to know.

What Is Title 24 Energy Compliance in California?

Title 24, Part 6, administered by the California Energy Commission (CEC), establishes minimum energy efficiency standards for residential and commercial buildings throughout the state. The standards are updated roughly every three years to reflect advances in technology and California's evolving climate goals.

The current standards cover six major areas: building envelope (walls, roof, windows, and floors), HVAC and water heating, indoor and outdoor lighting, solar energy systems, and electric vehicle (EV) charging readiness. For residential construction, Title 24 compliance is verified through an approved compliance software method — most commonly the prescriptive or performance approach — and documentation must be submitted with your building permit application.

Prescriptive vs. Performance Compliance

California offers two paths to meet the standards. The prescriptive approach requires your project to meet specific fixed requirements — a set R-value for insulation, a maximum U-factor for windows, and so on. The performance approach uses energy modeling software to show that your building's total energy use meets or beats a reference design. The performance path offers more flexibility, which can be valuable when one component falls short but is offset by efficiency gains elsewhere.

When Does Title 24 Apply to Your Project?

Title 24 energy compliance California applies any time a building permit is required. This includes:

• New home construction
• Home additions (any conditioned square footage added)
• Accessory dwelling units (ADUs), both attached and detached
• Garage conversions to living space
• HVAC replacements (partial compliance may apply)
• Window replacements when part of a permitted project
• Major renovations that affect the building envelope

Minor cosmetic projects — interior painting, flooring replacement, kitchen cabinet swaps — typically don't trigger Title 24 review. But any project that adds conditioned square footage or replaces a major building system usually does. When in doubt, check with your local building department before starting work.

Key Requirements Under Title 24

Understanding the specific measures Title 24 requires helps you make smarter design and material decisions early in the process.

Building Envelope Requirements

The building envelope — everything that separates conditioned interior space from the outside — must meet minimum performance thresholds. Proper insulation is one of the most cost-effective ways to meet these standards, and it pays dividends in comfort and energy savings long after your project is complete.

Bay Area homes span multiple climate zones — San Jose and Fremont fall in Zone 4, while coastal areas like Daly City sit in Zone 3. Each zone has slightly different prescriptive values, so confirm which zone applies to your address before finalizing your compliance approach.

Window upgrades are often a significant line item. If you're already considering a window replacement as part of your project, meeting Title 24's U-factor and SHGC requirements adds little cost when planned from the start — but retrofitting non-compliant windows after framing is complete can be expensive.

Mechanical and Lighting Systems

Beyond the envelope, Title 24 sets requirements for:

• HVAC: Minimum SEER2/HSPF2 ratings for heat pumps and air conditioners; duct sealing and insulation; thermostat controls
• Water Heating: Heat pump water heaters are now required in most new residential construction; solar-ready plumbing stubs in new builds
• Lighting: High-efficacy LEDs required throughout; vacancy sensors in specific rooms; daylight controls in certain applications
• Solar: New single-family homes must include rooftop solar PV systems sized to offset projected annual energy use
• EV Readiness: New homes must include dedicated 240V conduit and panel capacity for EV charging

Title 24 for Home Additions and ADUs

Home additions and ADUs don't always need to meet every standard applied to a fully new home — but the rules are more nuanced than many homeowners expect. For additions under 1,000 square feet, a simplified prescriptive approach is available. Larger additions and new detached ADUs typically require full compliance documentation.

ADU projects are among the most common triggers for Title 24 review in the Bay Area. Whether you're building a detached backyard unit or converting an attached garage, the new conditioned space must meet current energy standards. If you're navigating the full permit process for an ADU, our guide to Bay Area green building requirements covers complementary sustainability standards that may also apply to your project.

One important note: when an addition shares an HVAC system with the existing home, the entire system may need to be evaluated — not just the new square footage. Plan for this early to avoid surprises during plan check.

The Compliance Process Step by Step

Title 24 compliance is not a single inspection — it's a process that runs from design through final sign-off.

Design and Documentation Phase

Your contractor or energy consultant prepares a compliance report using state-approved software (CF1R form). This document details every energy-related feature of the project: insulation values, window specifications, HVAC equipment, and lighting layouts. The CF1R is submitted with your building permit application.

Construction Inspection Phase

During framing and rough-in, a HERS (Home Energy Rating System) rater may inspect insulation installation, duct sealing, and window placement before walls are closed. This is not optional — many measures require third-party field verification to be counted toward compliance. Required tests may include blower door (air leakage), duct leakage, and HVAC airflow measurements.

Final Documentation

Once all field verifications are complete, the HERS rater submits CF2R and CF3R forms to the state registry. Your building department reviews these alongside the final inspection before issuing a certificate of occupancy.

Working With a Contractor to Pass Compliance

The single biggest factor in whether your project passes Title 24 smoothly is choosing a contractor who treats energy compliance as part of their standard workflow — not an afterthought. At 9Builders, we include compliance planning in every project scoping conversation, coordinate with licensed HERS raters, and spec materials that meet or exceed current standards from day one.

This matters most on complex projects like multi-room additions, ADUs with independent mechanical systems, or remodels where the existing structure has significant air leakage. Getting compliance wrong means failed inspections, schedule delays, and change orders. Getting it right the first time keeps your project on time and on budget.

If you're planning a project that will require Title 24 documentation, contact our home additions team to discuss your scope and get an accurate estimate that includes compliance costs from the start.