Do Window Replacements Require a Title 24 Report?

Window replacements in California can trigger Title 24 energy compliance requirements depending on the scope of the project and the local jurisdiction. It is not always a simple yes or no. Here is what you need to know.

When Window Replacements Typically Require Title 24

Windows as part of a larger project

If you are replacing windows as part of a larger permitted project, such as a home addition, a remodel or another significant alteration, Title 24 compliance documentation will almost certainly be required as part of the overall permit package.

Standalone window replacements

For standalone projects (replacing existing windows with no other construction), what you need depends on local rules and on how much of the total window area is being altered. Some jurisdictions accept the product's rating label with the permit for a small replacement. Others ask for a Title 24 report when a significant share of the window area is replaced, when glazing is added, or when the new windows do not meet the standard requirements on their own. For the general triggers and exceptions, see when Title 24 is required.

Do You Need a Permit to Replace Windows in California?

Generally, yes. Most California building departments require a permit for window replacements, and nearly all do when the size of the opening changes or window area is added. Some jurisdictions treat certain same-size replacements more simply. Your building department decides, so check with them before you order windows. If they ask for energy documentation, it becomes part of the permit application. Our window replacement permit process page covers what usually happens.

Replacement vs. New Openings vs. Added Glazing Area

The code treats these three kinds of window work differently:

• Replacement in existing openings: old windows come out and new ones go into the same openings. The new units generally have to meet the requirements for replacement windows in your climate zone.
• New or enlarged openings: cutting a new opening or enlarging an existing one adds glazing area. That changes the home's energy performance, so the building department is more likely to ask for a report.
• Added glazing area overall: projects that add a meaningful amount of window area may need to show that the total glazing stays within the code's limits, or use the performance method to offset it elsewhere.

The exact area limits are in the code and change between cycles. Our window area thresholds page explains how they are applied.

Title 24 Window Requirements in California

Windows are a key variable in Title 24 energy compliance. Two ratings matter most:

• U-factor measures how much heat passes through the whole window. Lower is better insulating.
• SHGC (Solar Heat Gain Coefficient) measures how much solar heat comes through the glass. A low SHGC helps in hot, sunny areas.

Both values come from the window's NFRC (National Fenestration Rating Council) label, and the code sets maximum values that depend on your climate zone. Windows with a lower U-factor and a suitable SHGC for your zone make compliance easier, especially in hotter inland areas. For how the two ratings are used, see U-factor and SHGC for window replacements. For zone-specific notes, see examples such as Climate Zone 9 window requirements or Climate Zone 12 window requirements. Your exact zone is set by the project address.

Aluminum vs. vinyl windows under Title 24

Title 24 does not approve or ban a frame material. It looks at the rated U-factor and SHGC of the whole window as shown on the NFRC label. The frame affects those ratings: vinyl, fiberglass and wood frames usually conduct less heat than aluminum, so they often reach a lower U-factor more easily. An aluminum window can still comply if its rated values meet the requirement for your zone.

Can I use aluminum windows in California?

Yes, if the specific product's NFRC ratings meet the requirement or the performance model shows the home still complies. Thermally broken aluminum frames generally rate better than frames without a thermal break. Check the label before you buy, not after installation.

Prescriptive vs. Performance for Windows

There are two ways to show compliance. Under the prescriptive approach, each new window must meet the listed U-factor and SHGC for your zone, and glazing area must stay within the limits.

The performance approach models the home in CEC-approved software and compares it with a code-defined standard design. This allows trade-offs: a window that falls a little short can sometimes be offset by other features in the scope. It is often used when glazing is added or when windows are part of a bigger project. See Title 24 calculations for how the model works.

What the Title 24 Report Needs for a Window Project

For window work, the main compliance document is usually the CF1R. To prepare it, we typically need:

• A window schedule with the size and type of each window and glazed door
• The NFRC U-factor and SHGC of each product (spec sheets or quotes are fine)
• Which windows are existing, replaced, new or enlarged
• Floor plans and elevations showing where each window is and which way it faces
• The project address, so the correct climate zone is used

Our window replacement Title 24 report service covers standalone replacements and window work within larger projects.

Frequently Asked Questions

Do I need a Title 24 report to replace one or two windows?

Often not a full report, but the new windows still have to meet the code. Many building departments handle small replacements through the permit and the product labels. Ask your building department what they require.

Where do I find a window's U-factor and SHGC?

On the NFRC label on the window, and in the manufacturer's spec sheet or your supplier's quote. Send us those documents with your plans.

How much does a Title 24 report for windows cost?

Title24Comply residential reports start at $245, with standard turnaround of 2–3 business days. See Title 24 report cost for what affects the price.