Window & Door Replacement Questions, Answered.

Yes, completely free, with no obligation. We offer two options:

• In-home estimate: Alex or Leon comes to your home, measures accurately, walks through product options, and follows up with a written quote.
• Remote estimate: Send us photos of your existing windows or doors plus approximate measurements. We'll respond with a detailed written quote via email or text — usually within 48 hours, though we try to get back to you as fast as we can.

We're based in Walnut Creek and serve the entire East Bay and greater Bay Area, including:

Walnut Creek · Concord · Pleasant Hill · Lafayette · Danville · San Ramon · Martinez · Orinda · Brentwood · Clayton · Moraga · Alamo · Oakland · Berkeley · Pittsburg · Antioch · Oakley · Livermore · Dublin · and surrounding communities.

We also take on large-scale projects in San Francisco and San Jose.

Not sure if we cover your area? Call or text us, if we can get there, we will.

Three easy ways:

• Fill out the online estimate form. We respond within one business day.
• Call or text us directly at (925) 393-3578.
• Message us on WhatsApp, we're responsive and you can send photos directly in the chat.

Yes. Windows 4U holds California Contractor License #1097508 and is fully licensed, bonded, and insured on every project. You can verify our license directly on the California Contractors State License Board (CSLB) website at cslb.ca.gov. Just search license number 1097508.

Working with an unlicensed contractor in California means no warranty protections and potential liability for you as the homeowner. With us, you're always protected.

No. We specialize exclusively in full replacement, not repairs. We don't fix broken hardware, re-seal leaking frames, patch rotted wood, or service existing windows and doors. If something is broken, our answer is always a proper replacement. Done right, with a warranty.

If you're not sure whether you need repair or replacement, call us. We'll give you an honest assessment, and if a repair is genuinely the right call, we'll tell you that instead of pushing a sale.

No. We don't do glass-only replacement. We replace the full window unit: glass, frame, and all. Glass-only swaps are typically a stopgap that doesn't address the underlying issues (failed seals, aging frames, poor energy performance) and we don't offer that service.

Full window replacement gives you a new unit with a manufacturer warranty, better energy efficiency, and a proper installation warranty on our work.

No. We only install products we supply and order ourselves. We don't install customer-supplied windows or doors, regardless of brand or where they were purchased.

The reason is straightforward: sizing and fit are everything in window and door installation. When we order the product, we measure the opening, spec the unit, and take full responsibility for the result. When a product comes from somewhere else, we have no control over whether it was measured correctly, ordered to the right specs, or damaged in transit — and we won't put our name on an installation where those variables are out of our hands.

If you need product only, we're happy to supply it. If you need both product and installation, we handle the whole job. But we don't split it the other way.

Screens come included with the windows we install. We fit and install them as part of every window replacement job.

However, we don't offer screen-only service. We don't repair, replace, or re-screen existing window screens as a standalone job. If you need screen work independent of a window replacement, you'll need a screen specialist for that.

Yes. We actively welcome contractor and builder partnerships. We're well-equipped to handle high-volume and large-scale projects, including:

• Multi-unit residential replacements (apartments, condos, townhomes)
• New construction window and door packages
• Large whole-home remodels with multiple trades involved
• Property management company projects across multiple sites

We coordinate professionally, show up on schedule, and can work within larger project timelines. If you're a GC, builder, or property manager, reach out directly to discuss your project.

Both. Windows 4U installs all types of residential windows and doors:

• Windows: Casement, double-hung, bay & bow, picture, horizontal slider, awning, single-hung
• Entry doors: Front entry, back/side doors, house-to-garage (fire-rated)
• Patio & sliding doors: Sliding glass doors, French patio doors, multi-panel systems

Many homeowners do windows and doors together. We can quote both in a single visit.

We install all major residential window styles:

• Casement, hinged on the side, cranks open, maximum ventilation and energy efficiency
• Double-hung, both sashes operate, classic look, easy interior cleaning
• Single-hung, lower sash opens, budget-friendly classic
• Bay & bow, project outward, dramatic look, adds interior space
• Picture, fixed pane, maximum light and view, most energy efficient
• Horizontal slider, glides side to side, great for wide openings
• Awning, hinged at top, stays open in light rain, great for bathrooms and kitchens
• Arch, round & specialty shapes, half-rounds, circles, octagons, polygons, accent windows that add architectural character

We also install combination windows: a picture center with casements or single-hungs on the sides, a slider paired with double-hungs, or a standard window below an arch accent. Tell us what you have in mind and we'll spec it out.

Not sure which style is right for you? We'll walk you through the options during your estimate.

• Vinyl, most popular, lowest maintenance, excellent insulation, best value. Resistant to moisture and won't rot. Our most-installed material.
• Fiberglass, premium option. Stronger than vinyl, won't warp or expand in heat. Paintable to any color. It takes paint and holds it longer than wood. Best long-term investment.
• Aluminum, slim sightlines, modern look, great for large spans and contemporary homes.
• Wood, classic beauty. Paintable in standard exterior paint or lacquer for a premium finish. Best for historic homes and premium interiors. Requires the most maintenance.

All window materials we install meet California Title 24 energy code requirements.

Retrofit (pocket) replacement. We remove just the glass and sash from your existing frame and insert a new window unit. The frame and trim stay in place. This is faster, less expensive, and causes less disruption to your interior. It's the right choice when your existing frames are structurally sound.

Full-frame replacement (also called new construction). We remove everything (frame, sill, and exterior casing) down to the rough framing. This is the same process whether it's a replacement with a damaged frame or a new build: we go down to the studs, waterproof the opening properly, and install the new unit from scratch. Required when frames are rotted, leaking into the wall, or when you want to resize the opening.

We'll assess your windows during the estimate and recommend the right approach. We'll never upsell you to full-frame if retrofit will do the job properly.

Yes, noticeably. Modern double-pane windows with Low-E glass coatings significantly reduce heat gain in summer (less AC) and heat loss in winter (less heating). In the Bay Area, drafty single-pane windows are one of the biggest sources of energy loss in older homes.

Beyond energy savings, you'll notice rooms that used to be too hot or too cold staying more comfortable, less condensation, and noticeably reduced street noise. Many homeowners say the comfort improvement is even more impactful than the energy savings.

Energy Star certified windows may also qualify for federal tax credits, ask us which products qualify.

Clear signs it's time to replace:

• Drafts around the frame even when the window is closed
• Condensation or fogging between the glass panes (seal failure)
• Visible rot, warping, or water damage on the frame
• Windows that are difficult or impossible to open and close
• Outside noise is very loud, single-pane windows provide almost no sound insulation
• Your home is difficult to heat or cool and your windows are more than 20 years old

If you're not sure, send us photos, we'll give you an honest assessment.

We work with premium manufacturers that are well-established in the California market:

• Milgard, one of the most popular brands in California, strong warranty, great value in vinyl and fiberglass
• Alside, solid mid-range vinyl windows, reliable and energy-efficient
• Anlin, California-made, energy-efficient vinyl windows with a lifetime warranty
• Simonton, quality vinyl windows, wide style selection, good Energy Star options
• ProVia, premium windows and doors; excellent fiberglass options for high-end installs
• Marvin, premium wood, fiberglass, and aluminum-clad windows for upscale projects
• Windsor, durable wood-core and composite windows, great for traditional home styles
• Weather Shield, premium wood and fiberglass windows, excellent for Bay Area climates

We'll recommend the right brand for your budget and project during the estimate. Each brand has different strengths, there's no single "best," just what's best for your specific home and goals.

Costs vary depending on window style, size, material, and installation type. As a rough guide for the Bay Area market:

• Standard vinyl retrofit replacement: $400–$800 per window installed
• Fiberglass or wood windows: $600–$1,400+ per window installed
• Bay & bow windows: $2,500–$5,000+ installed
• Full-frame replacement: Add $200–$400 per window vs. retrofit

These are ranges, the only accurate number is a quote for your specific home. Our estimates are free and there are never hidden charges. The quote we give you is the price you pay.

Door costs depend heavily on material, style, glass options, and hardware:

• Standard steel entry door: $1,200–$2,000 installed
• Fiberglass entry door: $1,800–$3,500 installed
• Double door or door with sidelites: $3,000–$6,000+ installed
• Sliding glass door (2-panel): $2,000–$4,500 installed
• Patio / French door system: $2,500–$5,000+ installed

Contact us for a free estimate, we'll measure and give you a detailed quote with no surprises.

You get two warranties:

• 4-year installation warranty from Windows 4U, covers our labor and workmanship. If anything we installed has a problem due to how we installed it, we come back and fix it at no charge.
• Manufacturer's lifetime product warranty, covers defects in the window or door itself (glass seal failure, hardware, frame). This warranty transfers with the home if you sell.

Both warranties are in writing. You'll receive warranty documentation the day of installation.

Yes. Under the Inflation Reduction Act, homeowners may qualify for a federal tax credit of up to 30% (maximum $600 per year) for Energy Star certified exterior windows and skylights. This credit applies when you file your taxes for the year the windows were installed.

We can confirm during your estimate which products are Energy Star certified and provide the documentation you'll need for your tax return. Always consult a tax professional for advice specific to your situation.

Yes. We sell windows and doors as material only — installation is not required. This works well for contractors, builders, or homeowners who have their own licensed crew and just need quality product sourced and supplied.

We work with the same manufacturers we use on our own installs (Milgard, ProVia, Anlin, Marvin, and others) and can order to spec for your project. The manufacturer's product warranty still applies on material-only orders. Our 4-year installation warranty applies only to jobs we install ourselves.

If you're a contractor or builder, reach out directly to discuss pricing and lead times.

We're competitively priced for the quality and service we deliver, but we don't play price-matching games. What we will do is make sure you're comparing apples to apples, some contractors quote lower by using cheaper glass packages, skipping steps on the installation, or using subcontractors.

When you get a quote from us, it includes everything: the product, all hardware, proper installation, cleanup, a written warranty, and direct access to the owner. If another quote is genuinely for the same product and scope of work, we're happy to discuss it.