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Marvin Replacement Bay windows, made with Ultrex® fiberglass, feature three windows joined together to extend beyond the wall of your home. Consider a bay to fill your home with sunshine and fresh air.


  • Insulated head and seat boards available in standard pine or optional oak for bay window seating

  • Center unit can come as a picture unit or a window that opens and closes

  • Capture natural light from multiple angles

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Get your project started by booking a free appointment with one of our design consultants.




Strong Frame Material

Ultrex fiberglass is 8x stronger than vinyl windows to resist warping and shifting to protect your home.


Exceptional Stability

Ultrex expands 87% less than vinyl to resist leaks + seal failures for windows that open and close easily.


Design Flexibility

Customize your bay window with either casement or double hung windows to fit existing home style.


Charming Wood Interior Look

Select our EverWood® interior finish for the look of wood without the maintenance.


Fade-Resistant Finish

Our exterior acrylic finish stands up to 48,000 hours of sunlight.*

*(Average sunlight exposure based on 10 years)

Exterior view of a white Marvin Replacement bay window on white brick home.

Replacement Bay Window Design Options

Replacement Bay Window Styles

Marvin Replacement Bay windows harness the strength of our Ultrex fiberglass to project outwards from your home and make a room a focal point for extra architectural appeal.


Our bay windows are available in three-window configurations. Choose casement or double hung windows in your bay window. Customize the projection of your bay window with 30° or 45° side windows. Our bay windows create a cozy nook where you can soak up sunshine while relaxing with a book or tablet. Top off the look of your bay window with pine or oak veneer head and seat boards to match your home's style.

Selected: Operating Double Hung Bay

Marvin Replacement Three Wide Double Hung Bay Window
Marvin Replacement Casement Bay Picture Window
Marvin Replacement Three Casement Bay Window
Marvin Replacement Double Hung Bay Divided Lites
Marvin Replacement Three Wide Double Hung Bay Window

Exterior Colors

Our finish stands up to the elements, so much so that 48,000 hours of sun can't fade our finish* and our fade-resistant acrylic finish resists scratches, chalking, chipping, denting, and peeling. Choose from seven stunning exterior colors to boost your curb appeal.

Selected: Stone White

Stone white swatch
Sierra swatch
Cashmere swatch
Pebble Gray swatch
Bronze swatch
Bahama brown swatch
Ebony swatch
stone white color

Marvin's Ultrex® fiberglass finish is verified to the American Architectural Manufacturers Association (AAMA) 624 specification. Achieving AAMA 624 verification means that our Ultrex finish has passed rigorous tests that simulate the harsh conditions a finish can encounter throughout the life of a window or door.

*Average sunlight exposure per 10 years

Interior Colors

We use the same tough acrylic finish on our interior color options that we use on our exterior colors. You can also choose our stainable EverWood® finish for the look of wood without the maintenance.

Selected: Stone White

Stone white swatch
EverWood finish sample
stone white color

Finish samples are approximate. Schedule a design consultation for an up close view of color options.

Glass Coatings

Our experts will walk you through energy efficient glass options to find the right selection for your home and the best windows for your climate. Choose from four glass coatings, plus decorative glass options, and specialty glass choices.

Low E-1

Primarily used in colder climates, Low E1 allows more heat in to warm a room while blocking heat loss.

Low E-2

Low E2 offers year-round performance in moderate climates. It will help retain heat in your home during the winter and keep heat out during the summer.

Low E-3

Low E3 rejects solar heat while letting light in, resulting in increased performance in climates with intense sun exposure.

Low E-3/ERS

Low E3/ERS provides maximum efficiency year-round in all conditions.

Selected: Low E1

Diagram of Low E glass coating
Diagram of Low E2 glass coating
Diagram of glass with three metallic coatings.
Low E-3 ERS
Diagram of Low E glass coating

Decorative Glass

Decorative glass options are ideal for spaces like bathrooms to balance natural light and privacy.

Selected: Rain

Rain Glass
Glue Chip Glass
Narrow reed glass
Obscure Glass
Frost Glass
Marvin Replacement Reeded Decorative glass
Example of Marvin Replacement Gray Tint Decorative Glass
Sample of Marvin Replacement Green Tint Decorative Glass option.
Example of Marvin Replacement Bronze Tint Decorative Glass.
Rain Glass

Specialty Glass

We offer specialty glass to best suit the needs of your home. You can choose tempered glass, laminated glass, and STC/OITC glass for specific windows and rooms.

Tempered Glass

Tempered glass increases glass strength to help prevent breakage. Tempered glass is ideal for windows close to the floor or located in high-traffic areas.

Laminated Glass

Even more durable than tempered glass, laminated glass is often referred to as impact resistant or safety glass due to its vinyl inter layer that tends to remain in place when shattered.


Sound Transmission Class and Outdoor-Indoor Transmission Class glass has increased pane thickness on the room side and works in areas where exterior noise is a concern.

Divided Lites

We offer various divided lite patterns so you can replicate the look of your original windows and doors. Or, add new architectural interest to your home. Choose from Simulated Divided Lites for classic appeal or Grilles-Between-the-Glass for easy cleaning.

Casement windows can come with a Simulated Checkrail to create the look of a double hung window with the functionality of a casement. Patterns include: Cottage, Prairie 2-Wide, Prairie 6-Lite, Prairie 9-Lite, Rectangular, Prairie 2-wide 6-Lite, Simulated Checkrail, and Standard Pattern.

Selected: Grilles-Between-the-Glass

Cutaway of Marvin Replacement Grilles Between the Glass
Cutaway of a Marvin Replacement window with Simulated Divided Lites.
Marvin Replacement Casement Window Cottage Style
Marvin Replacement Casement Prairie Two Wide
View of a white Marvin Double Hung window with a Prairie 6 Lite divided lite style.
Image of a white Marvin Hung Double Hung window with a Prairie 9-lite style.
Image of a white Marvin Replacement Double Hung window with standard divided lite style.
Image of a Marvin Replacement Double Hung window with Rectangular Divided Lites.
Marvin Replacement Casement Prairie Two Wide Six Lite
Marvin Replacement Casement Prairie 9 Lite
Marvin Replacement Casement Window Simulated Check Rail
Casement Nine Lite Pattern
Cutaway of Marvin Replacement Grilles Between the Glass


Our tuckaway handle provides an uninterrupted view with casement bay windows and you can choose from eight different colors for your window’s hardware. You can also select our Clear View® hinge for maximum views.

Our casement windows come with a multi-point locking system to provide security, and seal out wind and weather.

Selected: Stone White

Satin Taupe
Satin nickel
brushed chrome
antique brass
Oil rubbed bronze
matte black
Casement window handle and lock

Screen Options

We have two durable aluminum-surround screen options that provide airflow while keeping insects out. Our standard Marvin Bright View™ fiberglass mesh has a clear view, sheds water, and resists dirt. Upgrade to our Hi-Transparency mesh screen for crisper views without losing any of our standard screen benefits. Color match your screen frames to the window for a seamless look.

Selected: Bright View Screen

Sample of a Marvin Replacement Bright View screen
Sample of a Marvin Replacement Hi Transparency window screen
Sample of a Marvin Replacement Bright View screen


To maintain bay windows, follow our glass cleaning guide and cleaning tips. Bay windows can follow the same cleaning guidelines as double hung and casement window cleaning, depending on which windows are featured in a bay window.

A woman wipes the glass on a Marvin Replacement Double Hung window with grilles between the glass.

Frequently Asked Questions

Bay window vs. bow window?

Bay windows and bow windows have similar characteristics but a bow window has sharper angles than a bow window, which is arranged in more of an arc.

How do you clean a bay window?

You can clean bay windows in the same manner as our casement and double hung windows.

Do bay windows open?

Most bay windows do not have three operable units. Typically, the two windows on each end can open and close while the middle window remains fixed. We do offer a three-window assembly where all three windows can open.

What is a flat bay window called?

A flat bay window is also known as a canted bay window or a classic modern bay window because it features a flat middle window and side windows at an angle.

What are the benefits of a bay window?

Bay windows can add more natural light to your home and create bigger views. A bay window can make your home more architecturally appealing with its angled lines. Bay windows can also help increase ventilation with operable flank windows or by having all three windows operable. A bay window seat comes with insulated head board to create a reading nook in your home.

Do bay windows let in more light?

Bay windows can let more light in because you have a three-window assembly versus having just a single window or two windows next to each other.

Are bay windows outdated?

Like many trends, bay windows have fallen out of favor at times and gained popularity at other times. Designers tend to think bay windows have come back in style, especially with people seeking more ways to add natural light to their homes.

Added Assurance

Marvin Replacement windows and patio doors come with a limited lifetime warranty as well as a 5-year installation warranty to provide additional peace of mind.

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Marvin Replacement Awning window in a bedroom with hardwood floor

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Marvin Replacement window installer places a window

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Discover the differences between fiberglass and vinyl windows, and why fiberglass windows have more strength.

Fiberglass vs. Vinyl Windows

Schedule Your Free Consultation

Interior view of an opened Marvin Replacement bi-fold patio door.

If you’re ready to get started, discuss your replacement window and door options with a design consultant. We’re here to answer any questions you may have, and help make your project easy.

Schedule your consultation