Uninsured window contractors can leave you liable for on-the-job injuries, property damage, or incomplete work that you'll need to pay to fix. Before signing any contract for window installation or replacement, verifying your contractor's insurance coverage is non-negotiable. Here's exactly how to do it and what red flags to watch for.
Why Insurance Matters for Window Installation
Window installation involves working at heights, handling glass, and operating power tools—all activities with genuine accident risk. If an uninsured contractor falls from your roof, gets injured, or damages your siding during installation, you could face a lawsuit or medical bills. Proper insurance protects both the contractor and you.
Additionally, most mortgage lenders and home insurance companies won't approve major exterior work without proof that the contractor carries liability coverage. Skipping this verification step can create financing or claims problems down the line.
Request Proof of Insurance Before Hiring
Don't accept verbal assurances. Ask the contractor for a Certificate of Insurance (COI) in writing before you schedule any work. The certificate should be issued by their insurance agent or broker, not the contractor themselves, and should include:
- General Liability Insurance: Covers property damage and bodily injury. For window work, look for limits of at least $1 million per occurrence and $2 million aggregate.
- Workers' Compensation Insurance: Legally required in most states if the contractor has employees. This covers their staff if someone gets hurt on your property.
- Proof of Active Coverage: The certificate must show current dates. Many contractors let coverage lapse between jobs—verify the expiration date is after your installation completion date.
Request that your address be listed as an "Additional Insured" on the liability policy. This extends protection to you if something goes wrong.
Verify the Insurance Directly
Don't assume the certificate is legitimate. Contact the insurance company yourself using the phone number on the COI (or look up the insurer's number independently—don't use contact info the contractor provides).
Ask the insurance agent or broker to confirm:
- The policy is active and hasn't been cancelled
- The coverage limits match what's on the certificate
- There are no exclusions that would prevent window installation claims from being covered
This verification takes 10 minutes and prevents major headaches. Some insurers will email you direct confirmation.
Check Licensing and Bonding Too
Insurance isn't the only protection layer. Your window contractor should also be:
- Licensed: Many states require contractors to hold an active license. Verify this through your state's licensing board website—search for the contractor's name and confirm their license is in good standing.
- Bonded: A performance bond guarantees they'll complete the work. If they abandon the job, the bonding company will cover completion costs (up to the bond amount, typically $5,000–$50,000 for window work).
Request proof of both. A legitimate contractor will provide these documents within 24 hours.
Red Flags That Should Stop You
Walk away if a contractor:
- Refuses to provide a Certificate of Insurance or gives excuses ("it's in the mail," "I'm between policies")
- Offers a significantly lower quote than competitors—sometimes this means they're cutting corners on insurance to reduce costs
- Has an invalid or expired certificate
- Won't allow you to contact their insurance company directly
- Claims they don't need insurance because they work alone (not true; liability coverage is essential either way)
- Requests cash-only payment with no written contract
Getting Competitive Quotes With Verified Contractors
When comparing window installation or replacement quotes, always request insurance verification alongside the estimate. This levels the playing field—you're comparing apples to apples, not cutting costs at the expense of protection.
Platforms like Mercoly let you compare and find trusted window installation providers in one place, complete with verified credentials and customer reviews, so you can make an informed choice faster.
Frequently Asked Questions
Q: Can a window contractor work without insurance? Legally, they can in some states if they're fully self-employed, but it's unwise—you assume all liability for accidents. Always require it.
Q: What's the typical cost range for window replacement? Most homeowners pay $300–$1,000 per window installed, depending on frame material (vinyl, wood, fiberglass), glass type, and labor rates in your region.
Q: How long does a typical window installation take? Most contractors install 3–6 windows in a single day; a full-home replacement of 10–15 windows typically takes 2–4 days with a crew of 2–3 installers.
Start verifying insurance today before you hire—it's the easiest way to protect yourself and ensure a smooth, liability-free installation.