The 2025 California Energy Code Is Already In Effect. Here Is What It Changes.

You scoped the project last year. You got numbers from your contractor over the summer. Then the drawings took longer than anyone planned, and the permit application went in sometime this year.

That project is now being reviewed against a code it was never priced for.

The 2025 update to Title 24, Part 6 took effect on January 1, 2026. Nine months later, we are still seeing commercial projects come across our desk that were built around the prior cycle's assumptions. The gap usually does not surface until plan check, which is the most expensive place to find it.

Your Permit Application Date Decides Which Code Applies

This is the single most important thing to understand, and it is the thing most owners get wrong.

Compliance is triggered by the date the permit application is submitted. Not the date you designed the building. Not the date you signed the contract. Not the date the bid was assembled.

Projects that applied for permits before January 1, 2026 stay under the 2022 Energy Code. Projects that applied on or after that date fall under the 2025 cycle. There is no grandfathering based on when the design started.

So if your project sat between a 2025 bid and a 2026 submittal, the budget and the code no longer match. The fix is straightforward if you catch it in design. It is a redesign if you catch it in a correction notice.

California Energy Code Alterations: The Part Owners Do Not Expect

A common assumption is that a new energy code only affects new construction. That has not been true for a long time, and it is especially untrue in this cycle.

The 2025 standards apply to new buildings and to additions and alterations to existing buildings. For a firm like ours, where a large share of the work is tenant improvements and commercial renovations, this is where most of the real impact lands.

Rooftop HVAC Replacement Is No Longer Like for Like

Under the 2025 code, when certain end-of-life rooftop HVAC units are replaced on stores, schools, offices, and libraries, they must be replaced with high-efficiency systems, including heat pumps.

This reclassifies the work. Many owners have historically treated a rooftop unit replacement as deferred maintenance, handled by a mechanical contractor off an operating budget, with a straightforward permit.

The scope is now wider than the unit itself. A higher-efficiency system can carry different electrical, structural, and control implications. Those questions need answering before the old unit comes off the roof.

Timing matters more than it used to. If you have aging rooftop equipment on a California commercial property, this belongs in your capital planning conversation now rather than on the day a unit fails in August.

Electric-Ready Requirements for Commercial Kitchens

The 2025 cycle establishes electric-ready requirements for commercial kitchens.

Read that carefully. It is not a mandate to install electric appliances. It requires that the infrastructure be in place so that a future conversion is possible without tearing the building apart.

In practice that is a panel capacity, conduit, and spatial planning discussion. It is inexpensive to solve on a drawing and costly to solve after the walls close. Restaurant and food service tenant improvements should be looking at this at the beginning of design, not at the end.

Title 24 Solar Requirements for Nonresidential Buildings

Section 140.10(a) of the current code requires solar photovoltaic systems on newly constructed nonresidential buildings across a broad list of occupancy types. That list includes offices, retail and grocery, restaurants, schools, medical office buildings and clinics, warehouses, hotels, libraries, religious worship, sports and recreation, and multifamily buildings of three or more habitable stories. There are defined exceptions.

Buildings that require solar PV are generally also required to include a battery energy storage system, again subject to specific exceptions, including one for single-tenant buildings under 5,000 square feet of conditioned floor area.

If you are developing new commercial space in California, solar and storage are not an upgrade conversation. They are a baseline design input, and they affect roof planning, structural loading, and electrical room sizing from the first sketch.

What Changed for Residential and Multifamily

For single-family homes, the code uses building energy budgets that encourage heat pumps for space conditioning and water heating, updates HVAC efficiency and control requirements, and tightens exterior wall and window performance.

For multifamily buildings, the cycle adds electric-ready provisions, strengthens ventilation standards for indoor air quality, expands electric vehicle charging through dedicated circuits and equipped parking spaces, and improves envelope requirements including wall and slab edge insulation.

CALGreen was updated on the same cycle, so green building requirements moved alongside the energy standards.

One Exception Worth Knowing

Executive Order N-29-25 temporarily suspends the 2025 update for projects involving the repair, restoration, demolition, or replacement of residential structures or facilities substantially damaged or destroyed by the 2025 Los Angeles area wildfires.

Those projects are not required to comply with the solar and battery energy storage requirements, but they must be solar-ready. If you are working on a rebuild in an affected area, confirm how your jurisdiction is applying this.

What To Do Before You Submit

Pull the energy compliance approach on any unsubmitted project. If the design work happened in 2025 and the application has not gone in, review it now.

Check your rooftop equipment ages. Commercial property owners should know which units are near end of life and what replacing them will now require.

Confirm local amendments. Cities and counties can adopt requirements that go beyond the state standard. The state code is the floor, not the ceiling.

Ask the question early. An energy compliance review during design takes an afternoon. Resolving it after a correction notice takes weeks and can reopen the budget.

Frequently Asked Questions

When did the 2025 California Energy Code take effect?January 1, 2026. It applies to new buildings and to additions and alterations to existing buildings.

Does the new energy code apply to my project if I designed it in 2025?It depends entirely on when the permit application was submitted. Applications submitted on or after January 1, 2026 fall under the 2025 cycle. Applications submitted before that date remain under the 2022 Energy Code.

Do I have to comply with Title 24 if I am only doing a remodel?Very possibly. The standards reach additions and alterations, not just new construction. Whether specific requirements are triggered depends on the scope of work, so a remodel needs an actual scope review rather than an assumption.

Do I need solar panels on a new commercial building in California?Newly constructed nonresidential buildings in a wide range of occupancy types are required to install solar photovoltaic systems under Section 140.10(a), and most of those buildings are also required to include battery energy storage. Defined exceptions exist, so the answer depends on building type, size, and tenancy.

Can I still replace a rooftop HVAC unit with the same type of unit?For certain end-of-life rooftop systems on stores, schools, offices, and libraries, the current code requires replacement with high-efficiency systems, including heat pumps. Plan the replacement as a design decision rather than a straight equipment swap.

Who enforces these requirements?Your local building department. The California Energy Commission writes the standards, but the authority having jurisdiction reviews and approves compliance, and local amendments can apply.

Talk To Someone Who Reviews These Every Week

Energy code cycles are not the interesting part of a project. They are the part that quietly decides whether your schedule and your budget survive plan check.

If you have a California commercial project that was scoped before this year, or a property with aging rooftop equipment, we can tell you quickly whether you have a problem and what it takes to solve it.

Avila Architects, Inc. is a California architecture and accessibility consulting firm serving clients statewide in English and Spanish. Art Avila is a California licensed architect, a Certified Access Specialist (CASp), a LEED AP BD+C, and a licensed general contractor, which means design decisions get evaluated for how they actually get built.

Visit www.avilaarchitectsinc.com to start a conversation.

Requirements described here are current as of September 21, 2026, and are based on the 2025 California Energy Code, Title 24, Part 6, as published with January 2026 errata. Local jurisdictions may adopt amendments that exceed the state standard, and project specific requirements vary. Confirm applicability with the building department having jurisdiction over your project.

Sources: California Energy Commission, "California's Energy Code Update Guides the Construction of Cleaner, Healthier Buildings," January 13, 2026 and the California Energy Commission Solar PV and Battery Energy Storage System support page.

This article is professional information from design and access professionals. It is not legal advice.

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