What Is Title 24? California's Energy Code Explained | BuildPermitGuide Glossary

Title 24 is California's Building Energy Efficiency Standards — a set of requirements for insulation, HVAC, windows, lighting, and more that apply to most permitted work in California.

Updated April 2026 Glossary Term

Title 24: Part 6 of California's Title 24 building standards, known as the California Building Energy Efficiency Standards, which establishes minimum energy performance requirements for new construction and renovations to reduce energy use and greenhouse gas emissions.

What Title 24 Covers

Title 24 Part 6 sets energy efficiency requirements for: building insulation (walls, ceilings, floors, foundations), windows and glazing (U-factor and solar heat gain coefficient), HVAC systems (efficiency minimums, duct sealing), water heaters, lighting (indoor and outdoor), and solar readiness. The standards are updated approximately every three years, with each update generally becoming more stringent.

When Title 24 Applies

Title 24 compliance is required for: new construction of any type, additions to existing buildings (the addition itself must comply), and alterations that trigger compliance requirements. HVAC replacements trigger duct leakage testing requirements. Window replacements trigger glazing compliance. Lighting alterations trigger lighting efficiency requirements. The extent of Title 24 requirements for alterations depends on the scope of work.

Title 24 Compliance Documentation

Title 24 compliance is documented through energy compliance forms — primarily the CF1R (Certificate of Compliance for newly permitted buildings) and CF2R and CF3R forms for installation verification and inspections. These must be filed with the building department as part of the permit application. A Title 24 energy consultant (HERS rater) is often required to verify compliance for HVAC-related work.

Title 24 and Solar

Since 2020, California's Title 24 requires solar photovoltaic systems on most new single-family homes. The 2022 update extended this requirement to new multifamily buildings. This is the most significant recent expansion of Title 24 — and one of the reasons California has the highest rate of new home solar installation in the U.S.

Frequently Asked Questions

It depends on the scope. HVAC replacements trigger duct leakage testing. Window replacements must meet current glazing standards. Lighting alterations trigger lighting efficiency requirements. Additions must meet full Title 24 compliance. Simple cosmetic work — painting, flooring — does not trigger Title 24.
A HERS (Home Energy Rating System) rater is a certified professional who verifies Title 24 compliance for HVAC systems and certain other measures. They're required to conduct duct leakage tests, verify HVAC installation, and sign off on compliance forms for HVAC permits. Your HVAC contractor typically coordinates the HERS rater.
Yes, meaningfully so. Title 24 compliance adds cost through higher-efficiency equipment requirements, duct leakage testing fees ($150–$400), more insulation, and documentation. For new construction, Title 24 compliance costs are estimated at $3,000–$15,000 per home depending on the design. But these costs are partially offset by lower energy bills over the home's life.
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