California Title 24 Energy Code Changes: What Homeowners Need to Know in 2026

If you are a California resident thinking about replacing your windows, upgrading your entry door, or tackling a remodel this year, don’t rush it. California's building energy code changed on January 1, 2026, and it likely affects your project.

California Title 24, formally known as the California Building Energy Efficiency Standards, sets the rules for how energy-efficient your home needs to be whenever you pull a permit. It covers everything from insulation and HVAC systems to windows, doors, and skylights. The state updates it every few years, and the 2025 version (effective January 2026) is among the most significant in the title’s history.

The good news is that understanding what changed doesn't require extensive knowledge or familiarity with state code. In this guide, we break it down in plain language so you know what to expect before your next project starts.

What Is California Title 24, and Why Does It Matter?

If you haven’t heard of Title 24, its purpose is straightforward: Title 24 is California's comprehensive energy code for buildings. It's part of the California Code of Regulations and sets minimum standards for energy efficiency across new construction, additions, and alterations to existing homes. The California Energy Commission (CEC) is responsible for adopting and updating these standards. That means local building departments are responsible for enforcing them.

What many homeowners do not realize is that Title 24 is not just for new builds. It applies to remodels and alterations, too. Before a local building department issues a permit for any qualifying project, they'll review your Title 24 compliance documentation to make sure everything checks out.

What does this mean? Essentially, if your project requires a permit, it likely needs to meet Title 24 requirements.

What Changed in Title 24?

The 2025 Title 24 standards that went into effect on January 1, 2026, represent a meaningful step forward in California's push toward carbon neutrality by 2045. The update was adopted by the California Energy Commission in September 2024 and is projected to save $4.8 billion in energy costs and reduce greenhouse gas emissions by approximately 4 million metric tons over time.

For residential homeowners, the most relevant changes fall into three areas:

• Stricter window and door performance requirements: The new code introduces “climate-zone-specific fenestration requirements,” meaning the energy efficiency and structural integrity of windows, doors, and skylights. This is a move away from the simple statewide benchmark that the industry had relied on for years. California has 16 climate zones, and each now has tailored performance mandates for windows and doors based on regional heating and cooling demands.

• Expanded heat pump requirements: California is promoting heat pump adoption, with a goal of 500,000 installations within the first three years of implementation. In some cases, homeowners replacing an air conditioner in a single-family home may be required to switch to a heat pump system rather than a like-for-like HVAC replacement.

• Tighter standards for ADUs and additions: Accessory Dwelling Units (ADUs) face increased attention under the 2026 update. These smaller structures often have a high glass-to-wall ratio, making high-performance windows and patio doors a necessity, rather than an upgrade.

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The Big One for Homeowners: Title 24 Windows and Doors

Windows and doors, collectively called "fenestration" under the code, are one of the most scrutinized elements of any Title 24 review. Heat gain and loss through windows and doors can account for up to 25-30% of a home's heating and cooling energy use. The 2026 update makes the performance bar for these products higher and more precise than before.

Here's what California homeowners need to know:

U-Factor measures how well a window or door resists heat transfer. The lower the number, the better the insulation. Under the updated code, many California climate zones require a U-Factor of 0.30 or lower. In some zones, like Climate Zone 3 (the Bay Area), the requirement tightens to 0.27. These are maximum allowed values, not targets. A window rated 0.31 won't pass inspection, but one rated 0.28 will.

Solar Heat Gain Coefficient (SHGC) measures how much solar heat a window lets into your home. A lower SHGC means better heat blocking, which is important for California's sunny climate. The 2026 standards require an SHGC of 0.23 or lower in most residential applications.

Dual glazing and Low-E coatings are now standard. All new and replacement windows must be dual-glazed and meet the Low-E2 standard. Single-pane windows are simply no longer an option for permitted work.

Doors with more than 25% glass surface area are treated as fenestration under the code. This means your doors must meet the same U-Factor and SHGC requirements as windows. Patio doors, French doors, and most entry doors with glass panels all need to comply.

You might be wondering: do these changes apply to all my new doors and windows? One important detail is that for major renovations, window replacements of 75 square feet or more must comply with the updated Title 24 energy requirements. Smaller replacements may have more flexibility, but it's always worth verifying with your local building department before you order.

How Do You Know If Your Windows Are Compliant?

Every legal window sold in California comes with a label from the National Fenestration Rating Council (NFRC). Think of it like a nutrition label for your glass: it lists the specific U-Factor and SHGC ratings that building inspectors will check at final inspection. Those labels must remain on the windows until after the inspection is complete.

If you're buying windows online or from a big-box retailer, be careful. Many off-the-shelf products won't meet the 2026 California energy code standards. If the NFRC label is missing or the numbers are too high, your inspector won't sign off, and that means costly delays and potentially having to replace the windows again.

The safest approach is to work with a contractor who sources Title 24-compliant products and handles the compliance documentation for you. Lifetime Home Remodeling works with you through every step of the remodeling process, including contracting and installation, which often involve trickier compliance considerations. 

Two Ways to Comply: Prescriptive vs. Performance Path

Title 24 gives homeowners and contractors two routes to compliance:

The Prescriptive Path is the straightforward option. If your project meets every specific requirement for your climate zone (such as the right U-Factor, the right SHGC, and the right glazing area), you automatically comply, and no energy modeling is required. The tradeoff is limited design flexibility. For example, your total window and glass door area generally cannot exceed 20% of your home's conditioned floor space under the prescriptive path.

The Performance Path allows for more flexibility. Using CEC-approved energy modeling software, a project can exceed requirements in one area (say, extra insulation) to offset a shortfall in another (like a larger glazing area). This path is especially useful for designs with large windows, open floor plans, or expansive patio doors. It typically requires an energy consultant, but for ambitious remodels, the flexibility is often worth it.

Most residential projects use the prescriptive path because it's simpler to document. But if your remodel involves significant glass — like a new sliding door wall or a major addition — the performance path may be worth exploring.

Related: Our Top Remodeling Mistakes You Don’t Want to Make

What This Means for Your California Home Improvement Project

If you're planning any of the following in 2026, Title 24 compliance must be part of the conversation if any of the following are a part of your project:

• Window replacement (especially 75+ sq. ft. of combined area)
• Entry door or patio door replacement (any door with more than 25% glass)
• Home additions or room expansions
• ADU construction or conversion
• HVAC system replacement, particularly if you're replacing an air conditioner

Projects permitted on or after January 1, 2026 must meet the new standards, but those that had permits pulled before that date may comply with the 2022 code. If your timeline is flexible, it's worth confirming with your contractor which code cycle applies to your project.

Related: Explore Our 2026 Home Remodeling Guide

Don't Let Compliance Catch You Off Guard

Regulatory changes like this one have a way of surprising homeowners after a project has started and after you've already committed to a timeline and a budget. The homeowners who have the smoothest experiences are the ones who ask the right questions before work begins.

Before you start, ask these of any contractor you work with:

• Are the windows and doors you're specifying NFRC-certified and Title 24-compliant for my climate zone?
• Will you handle the Title 24 compliance documentation and energy report?
• Does my project fall under the prescriptive or performance compliance path?
• Do the products you're recommending meet the 2026 U-Factor and SHGC requirements?

At Lifetime Home Remodeling, we stay current on California's energy code requirements so you don't have to. Whether you're replacing a few drafty windows, upgrading your entry door, or planning a larger remodel, we'll make sure your project is compliant from day one so there are no surprises at inspection.

Ready to make sure your next project is Title 24-ready? Contact Lifetime Home Remodeling for a free consultation.