How to Choose a Window Replacement Company ($900 a Window)

The checks that separate one window quote from another. The window labels come from the manufacturer; the license and lead rules are about the installer.

How do I check a window replacement company's license?

Ask which state or city license covers window work where you live, get the number, and look it up; then ask for the firm's EPA lead-safe certification if your home was built before 1978. Rules differ widely. Arizona's Registrar of Contractors requires a license on jobs over $1,000 or that need a permit, and lists window installation under its R-7 and C-7 carpentry classes. California's CSLB requires a license for jobs of $1,000 or more. Columbus, Ohio issues a Home Improvement Limited license that covers residential siding, windows and doors. Angi's Dallas guide says window contractors there do not need a state license, so in Texas the check moves to the city permit office and the company's insurance.

The lead rule applies everywhere. The EPA says about three-quarters of US homes built before 1978 contain some lead-based paint, and anyone paid to disturb paint in those homes must be lead-safe certified. Its minor repair exemption, up to 6 square feet a room inside or 20 square feet outside, does not cover window replacement under 40 CFR 745.83. Some states run the program themselves; Washington and Utah are two. City pages for Boston, Philadelphia and Columbus cover local permits and licenses.

What do the NFRC label and ENERGY STAR zones mean?

The NFRC label rates each window's U-factor, solar heat gain and other numbers so you can compare brands; ENERGY STAR sets pass marks for those numbers by climate zone. NFRC says the U-factor measures how well a product keeps heat from escaping a room, on a scale of 0.20 to 1.20 where lower is better. For solar heat gain coefficient, NFRC says "low numbers resist solar heat, high numbers allow solar heat."

ENERGY STAR version 7.0 window criteria as summarized by Andersen Windows, a manufacturer. ENERGY STAR publishes the official table by climate zone; check your zone on its map.

ENERGY STAR says to look for its label for your climate zone next to the NFRC label. Ask each company to put the U-factor and SHGC for every window on the quote, so you compare like for like. Local code can be stricter: California's 2025 Energy Code caps most replacement windows at U-0.27 and SHGC 0.23, per Elk Grove's permit form.

What questions should I ask a window company before hiring?

Ask for the NFRC numbers per window, the install method, the lead-safe certificate, the permit plan and both warranties; these are the items that make window quotes comparable.

• What are the U-factor and SHGC for each window you are quoting? NFRC says these are on the label.
• Is it ENERGY STAR certified for my climate zone? ENERGY STAR's criteria vary by zone.
• Insert or full-frame, and why? This Old House says full-frame suits rot, warping or a size change, and inserts suit sound, square frames.
• Is your firm lead-safe certified? Required for pre-1978 homes (EPA).
• What license do you hold here, and what is the number?
• Is a permit needed, and who gets it? HomeGuide says same-size swaps usually need none; changing the size means reframing at $50 to $200 more.
• Who honors the glass seal warranty? Structure Tech says a fogged sash is often replaced free or at low cost under the maker's seal warranty, using the serial numbers.
• What does your labor warranty cover, and for how long? Get it in writing; it is separate from the manufacturer's.
• Is removal and disposal of the old windows included?
• How long from order to install?

What are the red flags? Warning signs when buying replacement windows

Walk away from same-day discounts, a promised federal window tax credit for 2026, and anyone who will not name the NFRC numbers or show lead-safe certification on an older home.

• A federal tax credit promised for 2026 windows. The IRS says the Energy Efficient Home Improvement Credit, which capped windows at $600, does not apply to property placed in service after December 31, 2025.
• A price good only today. The FTC lists pressure for an immediate decision as a scam sign.
• Steering you to its lender (FTC).
• All up front or cash only (FTC).
• No NFRC numbers on the quote, so you cannot compare windows.
• No lead-safe certification on a pre-1978 home, which the EPA requires for paid window work there.
• Asks you to pull the permit (FTC).

How much should a window company charge for the first visit?

The cost guides price the installed window rather than the measuring visit: HomeGuide's 2026 average is $900 a window, and HomeAdvisor puts buy-and-install at $300 to $1,650.

National figures from cost guides, shown side by side and not averaged.

Ask whether a measure or design fee is charged and whether it is credited if you buy. Full price tables by frame and style are on window replacement cost.

What should be in a window replacement contract?

The contract should list every window by location, size, model, frame, glass and NFRC ratings, plus the install method, price, deposit, dates and both warranties.

• Company name, address, phone and license number, and start and completion dates (FTC).
• Each window: room, rough size, brand and model, frame material, glass package, U-factor and SHGC.
• Install method for each opening: insert or full-frame, trim and exterior finish.
• Lead-safe work practices for pre-1978 homes (EPA).
• Deposit within your state's limit. California caps it at $1,000 or 10%, whichever is less (CSLB); New York City says no more than 25% (DCWP).
• Warranties: the manufacturer's and the installer's labor warranty, separately.
• Your right to cancel. The FTC's Cooling-Off Rule gives 3 days for many sales of $25 or more made at your home.

Where do I complain about a window company?

Complain to the state or city contractor board that licenses the company, then to the attorney general; lead-safe violations go to the EPA or your state's lead program.

• California: CSLB's complaint process.
• Arizona: the Registrar of Contractors; its Recovery Fund pays up to $30,000 per claimant per residence on eligible homes.
• Massachusetts: the Home Improvement Contractor program for owner-occupied homes.
• Anywhere: the state attorney general or a local consumer protection office (FTC).

The call line on this page connects you to an independent local window company that serves your area and pays us for the referral; hours vary. We do not license, inspect or rate these companies, so run the same checks on whoever answers. How calls work. Ask for its license number and, for older homes, its lead-safe certificate on the call.

What to do before you hire a window company

1. Count the windows and note rough sizes, which floor, and any that are rotted or hard to open.
2. Check your ENERGY STAR climate zone and any local energy code limits.
3. Get two or three quotes that list each window's NFRC numbers and install method.
4. Look up each company's license; for a pre-1978 home, ask for the lead-safe certificate.
5. Ignore any federal window tax credit pitch for 2026 installs.
6. Sign a contract with every window listed and the deposit within your state's limit.