Window Replacement Contractor Checklist for Seattle Homeowners
You've received three quotes for new windows, and the prices are all over the map. One contractor promises a two-day turnaround, another mentions permits, and the third includes a warranty you've never heard of. How do you know who to trust?
Window replacement is one of the bigger investments you'll make in your Seattle home, and Western Washington's climate makes the decision especially important. Our long wet season, occasional windstorms, and humidity swings demand windows that perform—and contractors who install them correctly. This checklist will help you ask the right questions so you can compare quotes on substance, not just price.
Washington State Licensing and Insurance
Start with the basics that protect you legally. Washington requires contractors to be licensed, bonded, and insured, and you should verify all three before signing anything.
What to Ask About Credentials
"What's your contractor registration number?" Every contractor doing work over $1,000 in Washington must be registered with the Department of Labor & Industries. Ask for their registration number and verify it yourself at L&I's website. The license should be active, not expired or suspended.
"Do you carry liability insurance and workers' compensation?" General liability insurance protects your property if something goes wrong during the job. Workers' comp covers injuries to the crew. Ask for certificate numbers and verify them directly with L&I. If a contractor is working solo without employees, they may have a workers' comp exemption—ask to see documentation.
"Are you bonded?" Washington requires a surety bond. If the contractor fails to complete the work or violates contract terms, the bond provides a way to recover your money. The bond amount varies by the size of jobs they bid, but verify it exists.
Don't skip this step. Unlicensed contractors are common, especially for smaller jobs, but hiring one leaves you with zero recourse if disputes arise—and your homeowner's insurance may not cover damage caused by unlicensed work.
Permit Handling and Code Compliance
Window replacement typically requires a permit in Seattle and most King County cities, especially when you're changing the size of the opening or doing structural work. Even simple replacements often need permits to ensure energy code compliance.
What to Ask About Permits
"Will this project require a permit, and who pulls it?" A reputable contractor should know Seattle's permit requirements and handle the paperwork. If they say no permit is needed for a full window replacement, ask why—it's a red flag unless you're doing a true like-for-like swap in some jurisdictions.
"How long does the permit process take in Seattle right now?" Permit timelines fluctuate. As of recent years, Seattle's Department of Construction and Inspections has faced backlogs. A contractor familiar with local permitting should give you a realistic estimate and factor it into the project timeline.
"Who schedules the inspection?" The contractor should coordinate with the city inspector. You want confirmation that they'll be present for the inspection and handle any required corrections.
Permits add time and a few hundred dollars to the job, but they ensure your windows meet Washington's energy code (which is stricter than many states) and that the work is documented for future buyers.
Product Selection and Suitability for Seattle's Climate
Not all windows perform equally in Western Washington. Our climate isn't extreme cold, but the persistent moisture, UV exposure in summer, and temperature swings between rainy and dry seasons place specific demands on window performance.
What to Ask About the Windows Themselves
"What U-factor and Solar Heat Gain Coefficient do these windows have?" Washington's energy code sets minimums, but you want numbers appropriate for our climate. A U-factor of 0.30 or lower is typical for quality double-pane windows here. SHGC around 0.30 helps with passive solar gain in winter without overheating in summer.
"Are these windows rated for our wind and water exposure?" Seattle isn't coastal, but areas near Puget Sound or on hillsides face serious wind-driven rain. Ask if the windows meet NFRC (National Fenestration Rating Council) water penetration standards and what their design pressure rating is.
"What frame material do you recommend and why?" Vinyl is common and low-maintenance, but quality varies wildly. Fiberglass holds up better in UV and temperature swings. Wood offers beauty but needs maintenance in our damp climate. The contractor should explain pros and cons, not just push one product.
"Who manufactures these windows?" Research the brand. National brands like Milgard (which is Washington-based), Pella, Andersen, and Marvin have track records. Be cautious of house brands you can't research or verify warranties for.
Warranty Terms and Coverage
Window warranties are complex—often split between the manufacturer's product warranty and the contractor's installation warranty. Both matter.
What to Ask About Warranties
"What does the manufacturer's warranty cover, and for how long?" Glass seal failure (fogging between panes) is the most common issue. Good manufacturers warranty glass for 20 years or more. Frame and hardware warranties vary. Get the warranty terms in writing, and confirm whether it's transferable if you sell the home.
"What installation warranty do you provide?" This covers leaks, improper fit, and installation errors. A solid contractor offers at least a one-year installation warranty, often longer. Make sure it's in writing in your contract.
"What voids the warranty?" Some warranties are voided by painting vinyl frames, removing grids, or even power-washing. Know the restrictions upfront.
"If there's a problem in five years, will you still be in business to honor it?" This is awkward to ask, but longevity matters. Check how long the company has operated locally and look for reviews mentioning follow-up service.
Project Timeline and Process
A clear timeline prevents frustration and helps you plan around the work.
What to Ask About Scheduling
"What's the lead time from contract signing to installation?" Custom windows can take 6–12 weeks to manufacture. If a contractor promises next-week installation on custom work, they're either unusually well-stocked or overselling.
"How long will the actual installation take?" A typical single-family home with 10–15 windows usually takes two to four days, depending on complexity. If your home will be open to the elements overnight, ask how they'll secure openings—critical during Seattle's rainy months.
"What happens if weather delays the job?" Our wet season runs October through May. Rain can halt exterior work. A good contractor builds buffer time and communicates delays proactively.
"Will the same crew do the whole job?" Consistency matters for quality. You want to know who's showing up and that they're trained employees, not random subcontractors.
Pricing Transparency and Payment Terms
Price is important, but understanding what you're paying for matters more.
What to Ask About Cost
"Can you break down the quote—materials, labor, permits, disposal?" An itemized quote lets you compare apples to apples. If one bid is much lower, a breakdown shows whether they're skimping on window quality, cutting corners on prep, or underestimating permit costs.
"What's your payment schedule?" Never pay the full amount upfront. Typical terms: a deposit (often one-third) to order materials, a progress payment midway, and final payment upon completion and inspection. Washington law caps deposits for jobs over $1,000 at 50% of the contract price or $1,000, whichever is less—with some exceptions for custom materials.
"What's not included in this price?" Ask about interior trim, painting, drywall repair, disposal fees, or permit costs. These add-ons surprise homeowners and inflate the final bill.
"Do you offer financing?" Some contractors work with financing companies. Understand interest rates and terms before committing.
References and Past Work
Finally, confirm the contractor's track record.
What to Ask for Proof
"Can you provide references from recent Seattle-area projects?" Ask for three references, ideally within the past year, and actually call them. Ask about communication, timeline, cleanliness, and how problems were handled.
"Do you have photos of similar projects?" Before-and-after photos show quality of work. If they specialize in historic homes or modern builds, make sure their experience matches your home's style.
"Can I see a current job site?" Some contractors will arrange a visit. Seeing their process, crew professionalism, and site cleanliness tells you a lot.
Your Complete Vetting Checklist
Use this list when meeting with contractors:
- Licensing: Verified WA contractor registration, active bond, liability insurance, workers' comp or exemption
- Permits: Clear plan for pulling permits, realistic timeline, inspection coordination
- Product: Window specs (U-factor, SHGC), climate suitability, reputable manufacturer, frame material rationale
- Warranty: Manufacturer warranty details in writing, installation warranty length and coverage, transferability, exclusions
- Timeline: Lead time, installation duration, weather contingency, crew consistency
- Pricing: Itemized quote, payment schedule compliant with WA law, clear exclusions, financing options if needed
- Track record: Three recent references, project photos, possible site visit, online reviews
FAQ
Do I need a permit to replace windows in Seattle?
Most window replacements in Seattle require a permit, especially if you're upgrading to energy-efficient windows or altering opening sizes. Even like-for-like replacements often need permits to verify energy code compliance. Your contractor should handle permit applications and inspections. Skipping permits can cause issues during home sales and may violate city code.
How long do replacement windows last in Seattle's climate?
Quality vinyl or fiberglass windows typically last 20–30 years in Western Washington's climate, though seals may fail sooner if windows face south with heavy UV exposure or if installation was poor. Wood windows can last longer with proper maintenance but require regular painting or sealing in our damp environment. The key is proper installation with good flashing and drainage to handle our rain.
Should I replace all my windows at once or do it in phases?
Budget-wise, phasing is tempting, but replacing all windows at once is often more cost-effective—you'll get better per-window pricing, one permit fee, and one mobilization charge. Focus first on windows with failed seals, air leaks, or those facing our prevailing southwest weather. If phasing, prioritize west and south-facing windows that take the most weather abuse in Seattle. Coordinate with your contractor to ensure consistent product availability if you plan to match later.
The difference between a smooth window replacement and a nightmare often comes down to the questions you ask before signing. Take this checklist into every meeting, verify credentials independently, and trust contractors who answer thoroughly without defensiveness. Your Seattle home deserves windows that perform for decades—and a contractor who stands behind their work.