How to choose a window installer in Los Angeles

Written and checked by the DuloCore research team. Last verified: November 11, 2026.

A good window installer in Los Angeles is licensed for the work, pulls the LADBS permit, and hands you the paperwork the LADWP rebate needs; this checklist sits alongside the estimator on our home page.

The right CSLB license

• C-17 Glazing. The Contractors State License Board defines a glazing contractor as one who "selects, cuts, assembles and/or installs all makes and kinds of glass" and glazes frames, sashes and doors (CSLB C-17).
• B General Building. A B contractor may take a prime contract only if it involves at least two unrelated trades other than framing or carpentry, unless it holds the right specialty license or subcontracts to a properly licensed specialty contractor (CSLB B classification). A window-only job usually points to a C-17, or a B contractor using one.
• Look it up. Run every name through the CSLB license check. CSLB warns that seeing a license number does not mean the license is valid, and that salespeople must be registered as Home Improvement Salespersons (CSLB).

Insurance and bonds

A contractor with employees must carry workers' compensation, which you can see on the license record. Contractors must carry a $25,000 license bond, but CSLB notes that bonds do not assure a contractor's integrity or competence (CSLB).

Quotes you can compare

CSLB advises getting at least three written bids on the same scope and not automatically accepting the lowest (CSLB). For a Los Angeles job, ask each bidder to state:

• Who pulls the LADBS permit, and whether the job is a same-size Express Permit or needs plan check (see our permit page).
• The NFRC U-factor and SHGC for every window, so you can match the LADWP rebate and the Title 24 numbers.
• Installed dimensions per window on the invoice or order confirmation, which LADWP requires.
• Tempered glass if you are in a Very High Fire Hazard Severity Zone, and how HPOZ approval will be handled in a historic district.
• Retrofit insert or full-frame replacement, and how stucco or trim will be repaired.

Contract and payment rules

Home improvement jobs over $500 in labor and materials need a written contract that names the contractor, address and license number and says who obtains permits. The down payment may not exceed 10 percent of the price or $1,000, whichever is less, unless the contractor has a blanket performance and payment bond on file. You can cancel within three days of signing, mailed before midnight of the third day (CSLB contracts guide).

Red flags

• A deposit request above the legal limit, or cash only.
• "No permit needed" for a window that changes size or location.
• No NFRC labels or manufacturer order confirmation.
• A license number that does not verify, or a salesperson without an HIS registration card.
• A promise that the rebate is guaranteed; LADWP's own page says rebates are not guaranteed (LADWP).