In almost every case, yes—you need a permit to replace windows in California. Section 105.1 of the California Building Code requires a permit before an owner alters or replaces a regulated building component, and windows qualify because they affect the structural envelope, fire safety, and energy performance of the home.1ICC Digital Codes. California Building Code, Title 24, Part 2 – Section 105.1 Same-size, like-for-like swaps generally still require a permit; the local building department is the authority that decides.
When the Permit Requirement Applies
Section 105.1 uses broad language, covering anyone who intends to “construct, enlarge, alter, repair, move, demolish or change the occupancy of a building or structure, or to erect, install, enlarge, alter, repair, remove, convert or replace” a regulated system.1ICC Digital Codes. California Building Code, Title 24, Part 2 – Section 105.1 Replacing a full window unit sits inside that language. If you are also enlarging the opening or modifying wall framing, plan review becomes more involved because the structural change has to be evaluated.
Ordinary maintenance is treated differently. Replacing a single pane in an intact frame, swapping out hardware, or repairing weatherstripping is usually considered a repair rather than a replacement. If you are pulling out the entire unit, though, expect the permit requirement to apply. A quick call to your local building department will settle any borderline situation before you order materials.
Energy Ratings Your New Windows Must Meet
California’s Title 24, Part 6 governs the energy performance of every replacement window.2California Energy Commission. Building Energy Efficiency Standards Two ratings matter: the U-factor (how well the window insulates) and the Solar Heat Gain Coefficient, or SHGC (how much solar heat it lets through). Lower is better for both.
The 2025 Energy Code, in effect for 2026 projects, sets prescriptive maximums by California’s 16 climate zones under Table 150.1-A:3ICC Digital Codes. 2025 California Energy Code, Title 24, Part 6 – Section 150.1
- Climate Zones 1, 2, 3, 4, 5, 11, 12, 13, 14, and 16: maximum U-factor of 0.27.
- Climate Zones 6, 7, 8, 9, 10, and 15: maximum U-factor of 0.30.
- Climate Zones 2, 4, and 6 through 15: maximum SHGC of 0.23, with Climate Zone 15 requiring a stricter 0.20.
- Climate Zones 1, 3, 5, and 16: no prescriptive SHGC requirement.
In the San Francisco Bay Area (Climate Zone 3), for instance, replacement windows need a U-factor of 0.27 with no SHGC limit. In Los Angeles (Climate Zone 9), you need a 0.30 U-factor and a 0.23 SHGC. Your building department can confirm your zone. Every qualifying window carries a National Fenestration Rating Council (NFRC) label showing these values, and the inspector will check for it.4ICC Digital Codes. California Energy Code, Title 24, Part 6 – Section 110.6
The mandatory floor across every zone is a U-factor of 0.40. Anything worse cannot legally be installed in California.3ICC Digital Codes. 2025 California Energy Code, Title 24, Part 6 – Section 150.1
Safety Rules the Inspector Will Check
Emergency Escape Windows in Bedrooms
Every bedroom, habitable attic, and basement must have at least one window large enough for someone to climb out and for firefighters to enter. That rule comes from Section R310 of the California Residential Code.5ICC Digital Codes. International Residential Code – Section R310.1
Replacement windows get some relief. Under Section R310.2.5, a replacement bedroom window is exempt from the minimum opening-size and maximum sill-height requirements if it is the manufacturer’s largest standard window that fits the existing frame or rough opening, provides opening area equal to or greater than the old window (or matches its operating style), and is not part of a change of occupancy.6ICC Digital Codes. California Residential Code, Title 24, Part 2.5 – Section R310.2.5 The exemption exists because older openings often can’t fit modern egress dimensions without cutting into the wall. You should still maximize opening area within the existing frame rather than downsize.
Tempered Glass in Hazardous Locations
Safety glass is required in locations where the risk of someone falling into or through the glass is elevated. Section R308.4.3 of the California Residential Code defines a hazardous glazing location by four overlapping conditions: the pane is larger than 9 square feet, its bottom edge is less than 18 inches above the floor, its top edge is more than 36 inches above the floor, and a walking surface is within 36 inches of the glass.7ICC Digital Codes. California Residential Code, Title 24, Part 2.5 – Section R308.4.3 Windows near tubs, showers, hot tubs, stairs, and doors have their own safety glazing requirements under other subsections of R308. Specifying tempered glass in bathrooms and near doors is the safe default when in doubt.
Window Opening Control Devices
California requires window opening control devices (WOCDs) to reduce the risk of children falling from windows. These devices limit how far a window can open, generally to less than four inches, and must comply with ASTM F2090. They apply when an operable window sits more than 72 inches above the ground outside and the sill is low enough for a child to reach. Egress windows still need WOCDs, but the device must allow an adult to override it quickly so the window can open fully in a fire.
Lead Paint Rules for Homes Built Before 1978
Older homes bring a federal overlay. The EPA’s Renovation, Repair, and Painting (RRP) rule requires that any contractor working on pre-1978 housing be a lead-safe certified renovator and follow specific containment, cleanup, and disposal procedures.8US EPA. Lead Renovation, Repair and Painting Program Window replacement triggers RRP compliance regardless of how much paint is disturbed, because window channels and sills are among the most common sources of lead dust.
The RRP rule generally does not apply to homeowners working on their own homes. It does apply if you rent out any part of the home, run a child care facility in it, or buy and renovate homes for resale.8US EPA. Lead Renovation, Repair and Painting Program Before work begins, your contractor must give you the EPA’s lead hazard pamphlet and keep compliance records for three years.
HOA and Historic District Approvals
A city permit isn’t always the only approval you need. In an HOA community, the architectural review committee likely has its own standards for style, frame material, color, and sometimes manufacturer. Submit a separate application and get written approval before ordering. Violations can bring fines or forced removal.
Historic districts add another layer. Many California cities require design review or a certificate of appropriateness before you can alter the exterior of a historically significant building. Santa Barbara, for example, requires an evaluation by the city’s architectural historian before approving any window replacement permit on buildings over 50 years old, and repair is preferred over replacement.9City of Santa Barbara. Window Replacement
What to Submit With Your Permit Application
Most California building departments want a window schedule listing dimensions, frame materials, and glass types for every unit, plus a site plan or floor plan showing where each window sits. That lets the reviewer verify that bedroom windows meet egress rules and that bathrooms and other hazardous locations use safety glass. Your application also needs the NFRC-rated U-factor and SHGC values for the products you plan to install.
Hiring a contractor? You’ll provide their license number and proof of workers’ compensation insurance. Doing the work yourself? You’ll sign an owner-builder declaration. California Business and Professions Code Section 7044 lets homeowners work on their own principal residence without a contractor license, but only if they meet certain conditions, including having lived in the home for at least 12 months before the work is completed and not doing the work to prepare the home for sale.10Contractors State License Board. Building Officials – Owner-Builder Overview
Fees vary by jurisdiction. Small projects can run under $100; larger multi-window replacements with plan review can run several hundred. Ask your building department for a fee schedule before you file.
Contractor Licensing
California requires a state license for window work. The two relevant classifications are the C-17 Glazing Contractor license, which covers glass and window installation specifically, and the B General Building Contractor license, which covers a broader range of residential work.11Contractors State License Board. CSLB Licensing Classifications Either is acceptable for a window project.
There is a practical protection built into California law for homeowners who hire only licensed contractors: you are not legally required to pay an unlicensed person for their work, and you cannot be sued for non-payment.12Contractors State License Board. Consequences of Contracting Without a License Verify any contractor’s license on the CSLB website before signing.
The Final Inspection
When the installation is done, you schedule a final inspection. The inspector checks the NFRC labels to confirm energy compliance, looks for the etched tempered glass stamp wherever safety glazing is required, and examines the exterior flashing and weatherproofing. If something is wrong—a missing label, the wrong glass in a bathroom, sloppy flashing—you correct it and schedule a re-inspection. Annoying, but far less costly than finding out years later that water has been rotting the framing behind an uninspected window.
What Happens If You Skip the Permit
Three types of consequences follow unpermitted window work, and the financial ones land hardest.
Building department penalties come first. Licensed contractors who violate the code face civil penalties of up to $8,000 per violation from the Contractors State License Board, plus an order to pay permit fees and any local penalties.13Contractors State License Board. Building Code Complaint Many jurisdictions also charge double or triple the original permit fee as an investigation fee when unpermitted work turns up after the fact.
Insurance exposure comes next. Homeowners policies commonly exclude damage arising from unpermitted construction. If a poorly installed window leaks and causes mold or structural rot, your insurer may deny the claim on that basis.
Then there is resale. California Civil Code Section 1102 requires most residential sellers to complete a Transfer Disclosure Statement covering known material facts, and unpermitted renovations fall within that obligation. A buyer’s inspector or title company may flag the work, leading to price renegotiation, delayed closing, or a requirement that you retroactively permit the work and bring it up to current code before the sale can close.