Window, siding and deck warranties: what to read before you sign

Updated November 10, 2026 · KeystoneProGuide editorial team

What warranties come with an exterior job?

Often two, from two different businesses. The manufacturer of the windows, doors, siding or decking may warrant the product. The contractor may warrant the installation, often called a workmanship warranty. They cover different failures, last for different periods and are claimed in different ways, so read both before you sign the contract, not after something goes wrong. The Federal Trade Commission says that whenever there is a warranty, the law says it must be available for you to read before you buy.

What should you check in any warranty?

The FTC's questions apply to both kinds:

• Who stands behind it? Look up the company's reputation, the FTC says, for example by searching its name with "complaint" or "review", or by asking your state or local consumer protection office.
• How long does it last, and does coverage change or end after a set time?
• What is covered? If specific parts or repairs are not listed as covered, the FTC says to assume they are not.
• What will the company do? Repair, replace or refund?
• Who pays for labor? The FTC asks whether you have to pay for labor or shipping for repairs; for a window or siding fix, ask whether removal and reinstallation are included.
• What conditions apply? Some warranties require you to return a registration card, or cover problems only if the product was maintained and used according to the directions.
• How do you claim? Through the manufacturer, or back through the seller or installer?

Can installation void a product warranty?

Yes, according to ENERGY STAR. It says ENERGY STAR certified windows, doors and skylights must come with installation instructions, that some manufacturers void the warranty if those instructions are not followed, and that some warranties require an installer certified by the manufacturer. Ask the contractor, before signing, whether the installers are certified for the product you are buying, and get the answer in writing.

The building code points the same way. It requires window and door flashing to follow the fenestration manufacturer's instructions where they exist, and vinyl siding to be installed to the manufacturer's instructions and certified to ASTM D3679. For siding, the industry's trade association runs an installer certification for individuals and says its certified installers are trained to fasten vinyl so it can expand and contract; those are the association's claims about its own program.

There is a limit on what a manufacturer can demand. The FTC says federal law bars a manufacturer from requiring you to use specific parts or services to keep warranty coverage, unless it provides them free or has an FTC waiver. Where a window warranty insists on a certified installer, read exactly what it requires and ask the manufacturer if the terms are unclear.

What about the contractor's own warranty?

Get it in writing, in the contract. Pennsylvania's home improvement act requires the contract to contain the entire agreement between you and the contractor, so a workmanship warranty belongs in the contract itself, not only in a conversation or a brochure. The FTC says to get any spoken promise, such as free repairs, in writing, because a business might later refuse a service that was never written down. Its home improvement guidance makes the same point about any promises made during sales conversations.

Look for the same things as in a product warranty: what defects it covers (leaks around a window, siding coming loose, deck boards lifting), how long, whether it covers labor and materials, whether it transfers if you sell, and how to make a claim. If the deck builder's warranty depends on the deck being maintained, find out what maintenance it means.

Are extended warranties worth buying?

They are a different product. The FTC says an extended warranty or service contract costs extra and is sold separately, and that the warranty that comes with the product may already cover the same repairs for the same period. Compare the two before paying.

What other protections apply without a written warranty?

Implied warranties. The FTC says the laws of every state create unspoken promises that cover almost everything you buy, such as a promise that a product will do what it is supposed to do, and a promise that a product suits a particular purpose when you bought it on the seller's advice. They apply even without a written warranty unless the seller excludes them in writing. For your state's details, the FTC suggests a lawyer or a state consumer protection office.

What if a warranty is not honored?

Pennsylvania's Consumer Protection Law lists failing to comply with a written guarantee or warranty among unfair or deceptive practices, along with doing work below the quality agreed in writing. A consumer who loses money because of such a practice can sue for actual damages or $100, whichever is greater, and a court may award up to three times the damages, plus costs and attorney fees.

Before that, follow the FTC's steps. Contact the seller; if that fails, write to the manufacturer at the address in the warranty, by certified mail with a return receipt. The FTC says that if you report a defect during the warranty period and it is not fixed properly, the company must correct it even if the warranty expires before the fix. Keep the warranty, the receipt and, for windows, the ENERGY STAR and NFRC labels.

What should you do at the end of the job?

Collect every warranty document and registration card, register the products if the warranty requires it, and do not sign a completion certificate until the work is finished to your satisfaction, as the Attorney General advises. The rest of the closing steps are in what to expect, and the questions to raise before signing are in questions to ask. Listed businesses are on the exterior remodeling directory page.

Sources

1. Warranties, Federal Trade Commission
2. Residential Windows, Doors, & Skylights, ENERGY STAR (U.S. Environmental Protection Agency)
3. Chapter 7 Wall Covering, 2021 International Residential Code, International Code Council
4. VSI's Guide to Home Improvement Success, Vinyl Siding Institute (Polymeric Exterior Products Association)
5. 2008 Act 132 (Home Improvement Consumer Protection Act), Pennsylvania General Assembly
6. 1968 Act 387 (Unfair Trade Practices and Consumer Protection Law), Pennsylvania General Assembly
7. How To Avoid a Home Improvement Scam, Federal Trade Commission
8. Pottstown-Based Home Improvement Contractor Jailed at Least 3 Years for Taking More than $156K for Jobs he did not Complete, Pennsylvania Office of Attorney General