California Energy Code for Remodels: What Applies in 2026

The 2025 California Energy Code applies to remodels whose permit applications are submitted on or after January 1, 2026. If your project replaces windows, adds or moves lighting, changes HVAC or water heating, opens exterior walls or ceilings, or adds conditioned space, those parts of the work must meet the current California energy code. Purely cosmetic work, like new cabinets, counters or paint, generally does not trigger energy review.

For most remodels, the code applies to what you change, not the entire house. This guide explains what triggers compliance, what each system has to meet, how the paperwork and testing work, and how to plan so the energy code does not hold up your permit or your final inspection.

What the energy code is, and which version applies

California's Building Energy Efficiency Standards, known as Title 24, Part 6, are written by the California Energy Commission and updated every three years. The 2025 edition replaced the 2022 edition for permit applications filed from January 1, 2026.

The filing date is what decides which version governs. If your plans were drawn in 2025 but the permit application went in this year, your project falls under the 2025 standards. Plans that sat in a drawer for a year may need their energy calculations redone before submittal. Ask your contractor or designer to confirm the code cycle before the plans are finalized.

The 2025 cycle continues the state's push toward heat pumps for space and water heating, better ventilation and electric-ready homes. For a remodel, that mostly shows up in equipment choices and in planning electrical capacity when you replace gas appliances.

Which remodels trigger energy code compliance?

The edge cases catch people. A kitchen remodel that only swaps cabinets and a sink usually stays outside energy review. The same remodel with four new recessed lights does not. A bathroom update that replaces the tile stays cosmetic, but replacing the exhaust fan or adding fixtures brings in lighting and ventilation requirements.

Alterations vs. additions

For an alteration, the code applies to the components you change. New windows have to meet window requirements; new lighting has to meet lighting requirements. The rest of the house can stay as it is.

An addition is treated more like new construction: the new space has to comply on its own, or the addition and the existing house can be modeled together to show compliance. Newly built detached ADUs are generally treated as new homes, which can bring additional requirements such as solar. Our article on the California solar mandate explains when solar applies.

Key requirements by system

Windows

Every new or replacement window needs an NFRC label showing its U-factor and solar heat gain coefficient (SHGC). The required values depend on your climate zone. A window that works for a coastal home may not meet the SHGC target for a hotter inland zone, so choose windows for your address, not from a generic spec sheet. Our guide to double-pane vs. triple-pane windows covers how to compare those ratings.

Lighting

New and altered residential lighting must be high-efficacy, which today means LED fixtures certified to the state's requirements. Recessed downlights in insulated ceilings must be rated for insulation contact and air-tight. Controls matter too: lighting generally needs dimmers or vacancy sensors in many rooms, and bathrooms, laundry rooms and garages typically need at least one fixture on a vacancy sensor. Under-cabinet lighting in kitchens is usually switched separately from the ceiling lights.

HVAC and ducts

Replacing a furnace, air conditioner or heat pump, or extending ducts, usually triggers equipment efficiency requirements and duct sealing. Duct leakage testing and other checks are often verified in the field by a certified HERS rater. The 2025 code leans heavily toward heat pumps; ask your contractor whether your specific change-out triggers any heat pump or electric-ready requirements for your climate zone.

Water heating

Replacing a water heater brings equipment requirements into play. If you are switching to a heat pump water heater, plan for its space and airflow needs, a condensate drain and a dedicated electrical circuit. That can mean an electrical panel upgrade, which is far easier to plan during design than to discover during installation.

Insulation and air sealing

When you open exterior walls, attic floors or roof assemblies, the newly exposed areas may need insulation that meets current requirements for your climate zone. Air sealing around penetrations and top plates matters as much as the insulation itself.

Prescriptive vs. performance compliance

There are two ways to show compliance. The prescriptive path is a checklist: every component meets a set minimum. It is simple and works for most alterations. The performance path uses approved energy modeling software to show the project as a whole meets the target, letting you trade a better feature in one area against a weaker one elsewhere. Performance modeling is common for additions, because it can give credit for improvements to the existing house. Mandatory measures apply under either path.

The forms: CF1R, CF2R and CF3R

Energy compliance follows the project through three sets of documents:

• CF1R (certificate of compliance): submitted with your plans. It documents the energy features your design claims.
• CF2R (certificate of installation): completed by the installing contractor, showing what was actually installed.
• CF3R (certificate of verification): completed by a HERS rater for measures that require field testing, such as duct leakage.

Problems usually start when these documents disagree. If the CF1R lists one heat pump model and a different one gets installed, the paperwork has to be corrected before final. Plan-check corrections often come from small mismatches, like a window schedule on the drawings that shows different ratings than the CF1R.

Why your climate zone matters

California has 16 building climate zones, and many requirements vary by zone. Los Angeles County alone runs from mild coastal zones to hot inland valleys and high desert, and Orange County splits between coastal and inland zones. Your parcel's zone, not your city name, sets the targets on your compliance forms. The Energy Commission publishes climate zone maps and lookup tools, and your designer should confirm the zone before windows or equipment are chosen.

Some cities also adopt local energy or electrification amendments that go beyond the state minimum. Check with LADBS or your city's building department to see if any apply.

Common mistakes that delay remodels

Most energy code delays are not about the requirements themselves. They come from timing and paperwork. These come up most often:

• Ordering before checking. Windows or light fixtures bought before the compliance forms are prepared may not meet the requirements, and custom windows are rarely returnable.
• Substituting equipment. A supplier swaps the specified heat pump or water heater for a different model, and the forms no longer match what is installed.
• Forgetting the panel. A switch to a heat pump water heater or an electric range needs circuits and panel capacity that were never planned.
• Booking testing late. HERS raters can be busy. Waiting until the last week to schedule duct testing can push back your final inspection.
• Missing labels. NFRC stickers removed from windows before the inspector sees them, or cut sheets that are not on site, can mean a return visit.

Each of these is easy to avoid when energy requirements are discussed in the first design meeting rather than at plan check.

A permit-ready checklist

1. Confirm the permit application date and the code cycle that will govern it.
2. Confirm your climate zone.
3. Decide which spaces will be conditioned, especially in additions, garages and converted spaces.
4. Collect rated product data early: NFRC labels for windows, specification sheets for HVAC and water heating, and the lighting fixture schedule.
5. Cross-check the drawings against the CF1R so model numbers, ratings and fixture counts match.
6. Book a HERS rater as soon as equipment is selected, not the week before final.
7. Keep product labels and cut sheets on site for the inspector.

How Mr Build handles energy compliance

At Mr Build, Title 24 is part of design, not an afterthought at the permit counter. Our design, engineering and permit work is handled in-house through our partners, so energy calculations are prepared with the drawings and window, lighting and equipment selections are made with the compliance requirements in view. Every project gets a fixed, detailed written scope and a dedicated project manager who keeps installers, inspections and testing in sequence.

We have been remodeling homes in Los Angeles and Orange County since 1984. Learn more about our complete home remodeling services, see our work as a home remodeling company in Irvine, or schedule a free on-site consultation to review your project against the current code.

Sources and further reading

• 2025 California Energy Code energy.ca.gov
• regardless of project size pacificbuilders.com
• the current 2025 standards govern the project aldridgeconstruction.biz
• energy modeling software title24calcs.com