Seattle Fiberglass Windows
Fiberglass windows are crafted from high-quality glass fibers, using materials like silica sand, limestone, and soda ash. This blend is intricately woven and set through a resin bath before being cured in a high-temperature die. Our unique manufacturing process results in windows that are not only strong but also offer superior insulation. With options for either foam-filled or hollow core frames, these windows maintain consistent temperatures by expanding and contracting at the same rate as the glass pane they encase. This feature significantly reduces air leaks and enhances durability, making fiberglass windows an excellent choice for Seattle homes.
Why Choose Fiberglass Windows?
Fiberglass windows are the premium choice for homeowners who want the strongest, most energy-efficient, and lowest-maintenance window material available. Unlike vinyl or wood, fiberglass expands and contracts at nearly the same rate as the glass pane, which means tighter seals, fewer drafts, and longer-lasting performance over time.
| Vinyl | Fiberglass | |
|---|---|---|
| Material | PVC (Polyvinyl Chloride) | Glass fibers and resin |
| Cost | $ | $$ |
| Durability | Moderate | High |
| Maintenance | Low | Low |
| Energy Efficiency | Good | Excellent |
| Sound Insulation | Good | Excellent |
Fiberglass Window Benefits
- Fiberglass windows are the pinnacle of energy efficiency, making them the right windows for any energy-conscious homeowner.
- Known for their durability, these windows can last between 50-80 years, ensuring more money saved over time.
- Resistant to extreme temperatures and extreme heat, fiberglass does not warp, crack, or rust, requiring little maintenance.
- Available in a variety of styles and interior colors, fiberglass windows enhance your home’s curb appeal and suit any design preference.
- Fiberglass is an environmentally friendly choice, helping to reduce your carbon footprint and avoid harmful chemicals.
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The Finest Fiberglass Manufacturer Chosen For You
With more than 30 years in the window industry, we know what separates a good window manufacturer from a great one. That’s why we’ve chosen Milgard as our fiberglass partner. They’ve earned our trust through consistent quality, outstanding warranty support, and a commitment to innovation that keeps them ahead of the field — most recently with the launch of their next-generation C700 Series.
- Consistency of quality and service over the years
- Level of warranty support to you
- Industry longevity
- Product innovation
- Consistency of quality and service over the years
- Level of warranty support to you
- Industry longevity
- Product innovation
COMMERCIAL-GRADE Installation
Leak Armor Lifetime Installation Guarantee
When it comes to preserving the lifespan of your new windows and doors, installation matters. Thousands of window and door installations have honed our replacement process to perfection. For each project, our team follows a streamlined 3-step process to ensure you experience minimal delays and inconvenience before enjoying the benefits of your new window or door.
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Our Product Lines
Milgard C700 Series
Fiberglass Single Hung Windows
Milgard C700 Series Fiberglass Single-Hung Windows
The Milgard C700 Series single-hung window brings advanced fiberglass construction to a timeless window style. Designed for homeowners who value durability, clean design, and reliable performance, the C700 uses fiberglass frames that are built to handle decades of real-world conditions. Fiberglass is one of the most resilient and energy-efficient frame materials available today. Formed primarily from silica sand, it expands and contracts at nearly the same rate as glass, helping maintain tight seals that reduce drafts and limit long-term stress on caulking and surrounding materials. With its streamlined profile, expanded color palette, and improved thermal performance, the C700 single-hung window offers a premium replacement option well suited for homes across the Pacific Northwest.
Key Features
Built for decades of dependable performance. Fiberglass is one of the most durable window frame materials available, able to withstand years of Pacific Northwest rain, temperature swings, and moisture without swelling, rotting, or warping. Once installed, it requires minimal upkeep and continues performing reliably year after year.
Improved thermal efficiency comes standard. Every C700 window includes Milgard SunCoat® Low-E2 glass and delivers up to 10% better thermal performance than the previous generation. This helps maintain comfortable indoor temperatures while reducing the strain on your heating and cooling systems.
Helps reduce outside noise. Optional laminated glass packages help dampen exterior sound. Homes located near busy roads, flight paths, or active neighborhoods can experience a noticeable improvement in interior quiet once the window is closed.
A style that blends with your home. Six frame color options, coordinated hardware finishes, and a refined modern frame profile allow the C700 to complement a wide range of architectural styles, from traditional Craftsman homes to contemporary designs.
Backed by a trusted warranty. The C700 is protected by Milgard’s Limited Lifetime Warranty for residential homeowners, with the option to upgrade to a Full Lifetime Warranty at the time of purchase, offering added protection for a long-term investment.
Specifications
| Available Styles | Frame Color | Grid Styles | Grid Patterns | Hardware Features | Hardware Finishes | Screen Options |
|---|---|---|---|---|---|---|
| Horizontal Slider | White | 5/8" Flat | Standard | SunCoat® Low-E2 (standard) | SmartTouch® auto-locking hardware | White |
| Single Hung | Black | 15/16" Sculpted | Standard Half | SunCoatMAX® | Casement: dual-arm steel rotary operator, multi-point lock | Black |
| Casement | Bronze | Simulated Divided Lite (SDL) | Valance | Tinted Glass Options | Awning: single-arm scissor operator, dual lever lock | Bronze |
| Awning | Bark | 2-3/8″ Check Rail | Perimeter Pane | Obscure Glass Options | Bark | |
| Picture | Adobe | Perimeter Corner | Adobe | |||
| Steel Gray | Steel Gray | |||||
| Satin Nickel (upgrade) | ||||||
| Oil Rubbed Bronze (upgrade) |
Milgard C700 Series
Fiberglass Picture Windows
Milgard C700 Series Fiberglass Picture Windows
The Milgard C700 Series represents a new generation of fiberglass picture window design created for homeowners who want lasting durability, refined aesthetics, and dependable performance. Fiberglass frames are among the strongest and most energy-efficient materials available for residential windows. Manufactured primarily from silica sand, fiberglass expands and contracts at nearly the same rate as the glass it holds. This similar movement helps maintain tighter seals, reduces air leakage, and places less stress on sealants and surrounding materials over time. With a sleek contemporary frame profile, broader color selections, and improved energy performance, the C700 picture window is a premium replacement option well-suited for homes throughout the Pacific Northwest.
Key Features
Engineered for long-term durability. Fiberglass is one of the strongest window frame materials available, built to handle decades of wet Pacific Northwest weather without swelling, rotting, or warping. Once installed, it requires very little maintenance and continues performing year after year.
High-efficiency glass comes standard. Every C700 window includes Milgard SunCoat® Low-E2 glass and offers thermal performance improvements of up to 10% compared to the previous generation. The result is more consistent indoor temperatures and better energy efficiency throughout the year.
Helps create a quieter interior. Optional laminated glass packages significantly reduce outside noise. Homes located near highways, flight paths, or busy streets can experience a noticeable difference in sound levels once the windows are closed.
Low expansion/A design that fits any home. With six frame color options, coordinated hardware finishes, and a clean contemporary frame profile, the C700 blends easily with a wide range of architectural styles, from traditional Seattle Craftsman homes to modern new construction.contraction rate through 100-degree temperature changes means less glass and caulking failure over time
Warranty protection you can rely on. The C700 is covered by Milgard’s Limited Lifetime Warranty for residential homeowners, with the option to upgrade to a Full Lifetime Warranty at the time of purchase. Milgard stands behind the product to help protect your investment.
Specifications
| Available Styles | Frame Color | Grid Styles | Grid Patterns | Hardware Features | Hardware Finishes | Screen Options |
|---|---|---|---|---|---|---|
| Horizontal Slider | White | 5/8" Flat | Standard | SunCoat® Low-E2 (standard) | SmartTouch® auto-locking hardware | White |
| Single Hung | Black | 15/16" Sculpted | Standard Half | SunCoatMAX® | Casement: dual-arm steel rotary operator, multi-point lock | Black |
| Casement | Bronze | Simulated Divided Lite (SDL) | Valance | Tinted Glass Options | Awning: single-arm scissor operator, dual lever lock | Bronze |
| Awning | Bark | 2-3/8″ Check Rail | Perimeter Pane | Obscure Glass Options | Bark | |
| Picture | Adobe | Perimeter Corner | Adobe | |||
| Steel Gray | Steel Gray | |||||
| Satin Nickel (upgrade) | ||||||
| Oil Rubbed Bronze (upgrade) |
Milgard C700 Series
Fiberglass Casement Windows
Milgard C700 Series Casement Windows
The Milgard C700 Series casement window harnesses the resilience of fiberglass in a side-hinged, crank-operated design built for full ventilation. Fiberglass is among the toughest frame materials available, engineered from silica sand to flex at nearly the same rate as glass, keeping seals intact, drafts out, and weatherproofing performing for the long haul. A narrow modern frame, a broader range of exterior colors, and strong energy efficiency make the C700 casement an exceptional upgrade for Pacific Northwest homeowners.
Key Features
Durability designed for the long haul. Fiberglass frames resist swelling, rot, and warping through decades of Pacific Northwest rain and temperature swings, with minimal maintenance required.
Strong energy efficiency from day one. Standard Milgard SunCoat® Low-E2 glass delivers up to 10% better thermal performance than the previous generation, helping keep energy costs down year-round.
Quieter interiors when you need it. Available laminated glass options reduce outside noise, making a noticeable difference for homes near busy roads, flight paths, or high-traffic areas.
A design that fits many home styles. Six frame colors, coordinated hardware finishes, and a clean contemporary profile complement everything from Craftsman homes to modern new construction.
An Energy Star package calibrated for the Seattle region. Meets regional efficiency standards to help homeowners qualify for available rebates and reduce long-term energy costs.
Specifications
| Available Styles | Frame Color | Grid Styles | Grid Patterns | Glass Options | Hardware Features | Hardware Finishes |
|---|---|---|---|---|---|---|
| Horizontal Slider | White | 5/8" Flat | Standard | SunCoat® Low-E2 (standard) | SmartTouch® auto-locking hardware | White |
| Single Hung | Black | 15/16" Sculpted | Standard Half | SunCoatMAX® | Casement: dual-arm steel rotary operator, multi-point lock | Black |
| Casement | Bronze | Simulated Divided Lite (SDL) | Valance | Tinted Glass Options | Awning: single-arm scissor operator, dual lever lock | Bronze |
| Awning | Bark | 2-3/8″ Check Rail | Perimeter Pane | Obscure Glass Options | Bark | |
| Picture | Adobe | Perimeter Corner | Adobe | |||
| Steel Gray | Steel Gray | |||||
| Satin Nickel (upgrade) | ||||||
| Oil Rubbed Bronze (upgrade) |
Milgard C700 Series
Fiberglass Sliding Windows
Milgard C700 Series Fiberglass Sliding Windows
The Milgard C700 Series sliding window harnesses the resilience of fiberglass in a smooth, panel-gliding design built for easy operation and lasting performance. Fiberglass is among the toughest frame materials available, engineered from silica sand to flex at nearly the same rate as glass, keeping seals intact, drafts out, and weatherproofing performing for the long haul. A narrow modern frame, a broader range of exterior colors, and strong energy efficiency make the C700 slider an exceptional upgrade for Pacific Northwest homeowners.
Key Features
Durability designed for the long haul. Fiberglass frames hold up against decades of Pacific Northwest moisture and temperature swings without swelling, rotting, or warping, and require very little upkeep over time.
Strong energy efficiency from day one. Standard Milgard SunCoat® Low-E2 glass provides up to 10% better thermal performance than the previous generation, keeping indoor temperatures stable and energy bills lower.
Quieter interiors when you need it. Available laminated glass options cut down on outside noise, offering a calmer indoor environment for homes near highways, flight paths, or busy streets.
A design that fits many home styles. Six frame color options, coordinated hardware finishes, and a clean contemporary profile pair well with everything from classic Craftsman architecture to modern new construction.
An Energy Star package calibrated for the Seattle region. Meets local efficiency standards to help homeowners take advantage of available rebates and lower long-term energy costs.
Specifications
| Available Styles | Frame Color | Grid Styles | Grid Patterns | Glass Options | Hardware Features | Hardware Finishes |
|---|---|---|---|---|---|---|
| Horizontal Slider | White | 5/8" Flat | Standard | SunCoat® Low-E2 (standard) | SmartTouch® auto-locking hardware | White |
| Single Hung | Black | 15/16" Sculpted | Standard Half | SunCoatMAX® | Casement: dual-arm steel rotary operator, multi-point lock | Black |
| Casement | Bronze | Simulated Divided Lite (SDL) | Valance | Tinted Glass Options | Awning: single-arm scissor operator, dual lever lock | Bronze |
| Awning | Bark | 2-3/8″ Check Rail | Perimeter Pane | Obscure Glass Options | Bark | |
| Picture | Adobe | Perimeter Corner | Adobe | |||
| Steel Gray | Steel Gray | |||||
| Satin Nickel (upgrade) | ||||||
| Oil Rubbed Bronze (upgrade) |
Milgard C700 Series
Fiberglass Awning Windows
Milgard C700 Series Fiberglass Awning Windows
The Milgard C700 Series awning window delivers the strength and efficiency of fiberglass in a versatile venting design. Fiberglass is one of the most durable window frame materials available, made primarily from silica sand and engineered to expand and contract at nearly the same rate as glass. This helps maintain tight seals, reduce drafts, and limit long-term wear on caulking. With a slim modern profile, expanded color options, and improved energy performance, the C700 awning window is a premium replacement choice designed for the demands of Pacific Northwest homes.
Key Features
Durability designed for the long haul. Fiberglass frames are built to handle decades of Pacific Northwest weather, resisting swelling, rot, and warping even through constant rain and shifting temperatures. Once installed, they require very little maintenance to keep performing well.
Strong energy efficiency from day one. Every C700 window is equipped with Milgard SunCoat® Low-E2 glass and provides up to 10% better thermal performance than the previous generation, helping keep indoor temperatures more stable and energy use lower.
Quieter interiors when you need it. Laminated glass options are available to help reduce exterior noise. Homes near highways, flight paths, or active streets can enjoy a noticeably calmer indoor environment.
A design that fits many home styles. With six frame color choices, coordinated hardware finishes, and a clean modern frame shape, the C700 works well with everything from classic Craftsman architecture to modern homes.
An Energy Star package tailored to the Seattle region for optimal energy efficiency.
Specifications
| Available Styles | Frame Color | Grid Styles | Grid Patterns | Glass Options | Hardware Features | Hardware Finishes |
|---|---|---|---|---|---|---|
| Horizontal Slider | White | 5/8" Flat | Standard | SunCoat® Low-E2 (standard) | SmartTouch® auto-locking hardware | White |
| Single Hung | Black | 15/16" Sculpted | Standard Half | SunCoatMAX® | Casement: dual-arm steel rotary operator, multi-point lock | Black |
| Casement | Bronze | Simulated Divided Lite (SDL) | Valance | Tinted Glass Options | Awning: single-arm scissor operator, dual lever lock | Bronze |
| Awning | Bark | 2-3/8″ Check Rail | Perimeter Pane | Obscure Glass Options | Bark | |
| Picture | Adobe | Perimeter Corner | Adobe | |||
| Steel Gray | Steel Gray | |||||
| Satin Nickel (upgrade) | ||||||
| Oil Rubbed Bronze (upgrade) |
Comparing Fiberglass to Vinyl Windows
Compared to other window materials, we consider fiberglass the highest quality material available for your Seattle home. It provides optimal levels of performance and durability, along with many design options.
While fiberglass is more energy-efficient and durable compared to vinyl window materials, it’s also significantly more expensive. Because of this, we recommend fiberglass windows to homeowners who want the best material money can buy and vinyl windows for homeowners who desire comparable performance at a more affordable price. Finding the balance between performance and initial cost results in the maximum ROI from your new windows.
Fiberglass Window FAQs
Are Fiberglass Windows worth it?
The popularity of fiberglass windows is higher than ever. While the upfront cost is more significant, fiberglass provides benefits that vinyl windows do not. If you’re willing to spend the money upfront and reap the return on investment over time, then fiberglass windows are a worthwhile option for you and your home.
What style and color options are available with fiberglass windows?
Fiberglass is a versatile window frame material that can be molded and configured into most window styles. Milgard offers a range of interior and exterior colors, along with several different glass textures and window grids. Visit our window style page to explore the fiberglass options we provide.
Are fiberglass replacement windows durable?
Fiberglass windows do not damage easily. They will resist dents, scratches, warping, rotting, and corroding. The material is also strong and rigid, allowing fiberglass windows to be up to eight times stronger than vinyl windows and requiring much less maintenance.
How long does the fiberglass window installation process take?
At Lake Washington Windows and Doors, our installation process is down to a science. When embarking on a project with new customers, we generally schedule 2-5 days for installation, depending on the project size.
Fiberglass Window Frames Available in a Range of Styles
It doesn’t matter what window style you’re looking for. At Lake Washington Windows and Doors, we offer vinyl replacement window options in 6 of the 7 primary home window styles, including
Picture Windows
Fixed and non-opening, picture windows provide a clear, unobstructed view of the outdoors, allowing an abundance of natural light. They enhance the architectural aesthetic of your home, serving as a striking design focal point.
Casement Windows
These windows are hinged at the side and open outward, offering superior ventilation. Easy to operate with a crank or lever, casement windows boast a tighter seal for excellent insulation.
Single-Hung Windows
Featuring a fixed top sash and a movable bottom sash that slides vertically, single-hung windows are a cost-effective and popular choice. They provide a traditional look and are simpler to install than more complex styles.
Awning Windows
Hinged at the top and opening outward from the bottom, awning windows shield against rain while open and boost ventilation. Their unique design is ideal for adding airflow above doors or other windows.
Sliding Windows
With one sash sliding over another horizontally, these windows save space while offering ample ventilation. Perfect for areas with limited exterior space, like walkways, patios, or along busy streets.
Limited Time:
November Offers
Select your preferred discounts to get started with your free consultation:
Your Selected Offers
Schedule Your Free Consultation
Our Window Styles
Picture
Casement
Horizontal Sliding
Awning
Single Hung
Double Hung
Bay
Garden
Basement Hopper
Transom
Free In-Home Consultation
It all begins with a complimentary, no-pressure, in-home consultation where one of our window and door experts will assess your current design goals and functional needs, answer any questions you may have, and ask a few of their own before recommending the best premium quality window and door solutions.
Critical Measure
Next, our measurement technicians will visit your home at a time of your choosing to take exact measurements so we can place your order with exact specifications. Then, they will help to prepare you for your installation date.
Expert Installation
Finally, our installation experts will arrive on the scheduled date to replace your windows and doors, each equipped with our patented Leak Armor Guarantee, with thorough attention to detail. Once we finish installation, we’ll leave your property spotless, recycle your old materials, and leave you to enjoy your newly upgraded home.