How to choose a siding, window or deck contractor in Pennsylvania

Updated November 10, 2026 · KeystoneProGuide editorial team

What is the short version?

Choose a contractor whose state registration you have looked up yourself, whose insurance you have seen, who is certified for lead-safe work if your home was built before 1978, and whose written bid can be compared line by line with at least one other. Then sign only a contract that contains what Pennsylvania law requires. Each step below is something the Attorney General, the Federal Trade Commission or the EPA tells homeowners to do.

Step 1: Is the contractor registered with the state?

Ask for the registration number. Pennsylvania requires it on every ad, estimate and contract, as PA followed by digits. Then check it on the Attorney General's contractor search, which shows only active registrations, or by calling 1-888-520-6680. A number that is missing, or that belongs to a different business name, is a reason to stop.

A recent case shows why the lookup matters. In March 2025 the Attorney General announced that a Pottstown-based contractor had been sentenced to three to six years in state prison after taking more than $156,000 for work he did not finish. He had no registration of his own and gave homeowners another contractor's license information. One homeowner paid $108,747 and had to sell the house at a loss.

Registration is the floor, not a recommendation. The Attorney General says it is not an endorsement of honesty or quality, and that you should also check references, get more than one bid and look for complaints with the Better Business Bureau.

Step 2: Is the insurance real and current?

Registration requires proof of liability insurance of at least $50,000 for personal injury and $50,000 for property damage, and the contract must state the coverage in force when you sign. The FTC tells homeowners to ask for proof of insurance rather than take it on trust. Ask for a certificate naming the insurer and the policy dates, and call the insurer if anything looks off.

Step 3: Is the firm certified for lead-safe work?

If your house was built before 1978, this matters as much as registration. The EPA requires any firm paid to disturb paint in such a home to be certified and its workers trained, and its contractor guidance says window replacement is always covered, regardless of how little paint is disturbed. Carpentry, trim work and paint preparation are covered too, unless the job disturbs no more than 20 square feet outside or the paint has been tested and found free of lead. The EPA's advice to owners of pre-1978 homes is direct: hire a lead-safe certified contractor. Ask to see the firm certificate and the certified renovator's course certificate, which the EPA says must be kept on the job site.

Step 4: Do the bids describe the same job?

The FTC says a written estimate should describe the work, the materials, the completion date and the price, that you should not automatically choose the lowest bidder, and that you should ask why when estimates differ widely. For windows, ENERGY STAR suggests asking each installer to split the price into labor and materials, since different dealers may quote different prices for the same product. For siding, ask whether removal of the old siding, repair of damaged sheathing, new trim and flashing are included; for a deck, whether the permit, footings and railings are.

A useful test of any bid is whether it names a specific product line, size and finish. A contract under the act must include specifications that cannot change without a signed change order, and a bid that is vague now will be hard to hold to later.

Step 5: Who will actually do the work?

The company that sells you the job is not always the one that installs it. The act counts a retailer's installer as a contractor whatever the retailer's size, the contract must list known subcontractors, and subcontractors must be registered too, so you can check them the same way. Ask whether the installers are trained on the product being used. ENERGY STAR notes that some window warranties require an installer certified by the manufacturer, and that some manufacturers void the warranty if their installation instructions are not followed. For vinyl siding, the industry's trade association runs an installer certification for individuals; it says candidates need at least two years of experience, and the association's claims about its program are its own.

Step 6: What do references and complaints show?

Ask for two or three recent customers with a similar job, and ask them whether the crew showed up when promised, whether the price changed, and how problems were handled. The FTC suggests searching the company's name with words like "complaint" or "review", and checking with consumer protection officials. In Philadelphia, the city's lookup tool lists every actively licensed contractor and any licensing violations.

Step 7: Does the contract meet the law?

Before you sign, check that the contract has the registration number, a street address, start and finish dates, the product specifications, the total price, the deposit and any special order amount listed separately, the subcontractors, the insurance amounts and a notice of your three-day right to cancel. On a job over $5,000, the deposit may not be more than one-third of the price plus named special order materials. The full list, and the clauses that make a contract voidable, are in what Pennsylvania requires. The FTC adds two plain rules: make sure every blank space is filled in, and get any spoken promise in writing, which applies to warranty promises as much as to price.

What if the job uncovers something hazardous?

Old siding and trim can hide materials that need their own specialist. The EPA says you generally cannot tell whether a material contains asbestos by looking, and that if you plan to remodel, an inspection by a trained, accredited professional may be worth having. It also advises using two different firms to assess and to remove asbestos, so the one deciding whether removal is needed does not profit from the answer. Ask your contractor, before signing, what happens to the price and schedule if such material is found.

Where should you start?

Prices are in the cost guide, and businesses serving your area are on the exterior remodeling directory page.

Sources

1. Home Improvement Contractor Verification, Pennsylvania Office of Attorney General
2. Home Improvement Contractor Search, Pennsylvania Office of Attorney General
3. 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
4. 2008 Act 132 (Home Improvement Consumer Protection Act), Pennsylvania General Assembly
5. How To Avoid a Home Improvement Scam, Federal Trade Commission
6. Renovation, Repair and Painting (RRP) Program: Consumers, U.S. Environmental Protection Agency
7. Renovation, Repair and Painting Program: Contractors, U.S. Environmental Protection Agency
8. Residential Windows, Doors, & Skylights, ENERGY STAR (U.S. Environmental Protection Agency)
9. VSI's Guide to Home Improvement Success, Vinyl Siding Institute (Polymeric Exterior Products Association)
10. Find a licensed contractor and contractor information, City of Philadelphia
11. Protect Your Family from Exposures to Asbestos, U.S. Environmental Protection Agency
12. Warranties, Federal Trade Commission