The California 2025 Title 24, Part 6 update marks a significant pivot toward decarbonization, electrification, and whole-lifecycle energy thinking. Examples of this transition include replacing the established energy metric of Time Dependent Value “TDV” with Long-Term System Cost “LSC,” tightening electrification requirements, embedding photo-voltaic “PV” combined with battery energy storage systems “BESS,” and enforcing smarter controls. With this code update, California is firmly advancing its mission toward net zero and a carbon-neutral future in 2045.
Let’s take a look at some of the more impactful changes that will shape the California building industry for years to come.
From an energy accounting viewpoint, a major conceptual shift involves moving from the Time Dependent Valuationenergy metric and Energy Design Rating to Long-Term System Cost. LSC factors in lifecycle costs, emissions, and grid impacts, in an effort to move toward a more holistic energy metric. From an energy compliance model standpoint, this change is systemic, touching everything from lighting, ventilation, and building envelopes to performance targets of baseline versus proposed energy use.
An example in practice of this shift is the 2025 code’s prioritization of heat pumps for space and water heating in both new and existing buildings, which also includes the phase out of gas appliances in many cases. New infrastructure mandates will also include heat pump-ready features, adequate ventilation, dedicated circuits, space allowances for equipment and control readiness.
The California Energy Commission estimates this shift will catalyze 500,000 heat pump installations within the first three years, cutting around 4 million metric tons of greenhouse gases and saving 4.8 billion in energy costs statewide over the same period. In addition, PV and BESS requirements will now expand to include nonresidential, high-rise multifamily, and other specific assembly-type buildings including libraries, restaurants, and sports and religious venues. The code update expands upon 2022 code requirements to differentiate methods for calculating PV and BESS capacities dependent upon use, roof type and solar accessible roof area, and condition floor area.
Continuing to focus on optimizing building energy performance, the updates also include new provisions for building envelopes, HVAC, and ventilation criteria. Stricter thermal envelope requirements will include overall lower U-factors for walls, roofs, and windows (for example ≤ 0.47 for vertical fenestrations, and tighter wall insulation limits). Vestibules or equivalent air curtain measures will also now be required where applicable based on occupancy type to reduce infiltration. More efficient SEER thresholds will apply to dedicated outdoor air systems (DOAS), variable refrigerant flow equipment (VRF), and heat pumps. Mandatory use of ASHRAE Guideline 36 will be required for control sequences of variable air volume systems (VAV), economizers, and more. The new code will also bring cooling and heat recovery efficiency mandates, and specific prescriptive controls for systems based on load. Pipe insulation requirements will now extend to process heating and cooling lines, including new insulation equation rules.
The update also introduces new requirements for lighting, controls, and indoor air quality. Daylighting controls will be expanded, primarily to trigger at lower wattage and for more zones. In addition, the tailored method for lighting compliance will be removed, leaving only the complete building or area category methods for compliance. Requirements for outdoor lighting and sign illumination will tighten to only allow LED or neon sources for signs. New formulas to demonstrate ventilation compliance will be introduced, as well as mandates for balanced ventilation systems (HRV/ERV) for multifamily buildings. Acceptance testing for ventilation will also be required.
In many ways, California is setting a standard for decarbonization with the newest code iteration. Verdical Group’s upcoming Net Zero Conference is a great opportunity to learn more about upcoming code requirements and other strategies for electrification, sustainability, and net zero design. Hosted at the Los Angeles Convention Center on October 1, the event convenes building professionals and climate leaders to re-envision the built environment and inspire a net zero future.
The conference is a hub for people in the industry to gather, bridge knowledge gaps, and inspire a net zero future. It will feature inspiring keynotes, educational sessions, an expo hall featuring leading decarbonization technologies, and the Trailblazer Awards Ceremony. This year’s keynotes include Joel Cesare (Growth Lead, Cambio), Leah Thomas (Environmentalist), and Nalleli Cobo (Environmental Activist), and Michael Ford (The Hip Hop Architecture Camp).
You can register to attend the 12th annual Net Zero Conference here. USGBC California community can receive 15% off any ticket type using the code NZMP15.
Posted 9/19/25
About the Author
Rudy De La O, LEED AP BD+C, LEED Green Rater, TRUE Advisor, Fitwel Ambassador, Sustainability Excellence Associate, WiredScore AP, is a Commissioning Associate at Verdical Group, where he participates in all aspects of the building commissioning process.
He draws on two decades of experience in the AEC industry to make sustainability accessible and practical for clients on a project-by-project basis. His experience includes due diligence and project feasibility, managing entitlements, code analysis, project advocacy and stakeholder engagement, client representation, permit procurement, competitive bid facilitation, contract management, construction coordination, building commissioning, and sustainable design implementation.
Project focus areas include LEED stewardship (BD+C NC, Homes, Core and Shell, Neighborhood Development, Warehouse and Distribution Centers, Commercial Interiors), National Green Building Standard (NGBS), CALGreen compliance, Fitwel, Building Commissioning, and ESG goal setting.
Rudy actively volunteers to promote social resiliency through mentorship by teaming with various nonprofits. He has provided college and career guidance for first generation students from underrepresented communities and undergraduates pursuing careers in sustainability, and he has served as a board member for youth athletics.
