The exterior of a home with stone and brick, featuring Infinity windows.

The stunning strength of fiberglass replacement windows

Built with Ultrex^®, our 100% fiberglass material, Infinity from Marvin windows transform your home with 8x the strength of vinyl. Enjoy sweeping views, unmatched comfort, and a lifetime of beauty.

Why Infinity Replacement Process

Awning window

Maximize light and airflow in tight spaces with a top hinge.

Bay window

Open your space with more dimension and natural light.

Bow window

Create airier rooms with a gentle curve that captures more light and fresh breezes.

Casement window

Enjoy uninterrupted views and inviting breezes with a standard Easy Wash® hinge for simple cleaning.

Double hung window

A classic look with more ventilation and easy-clean tilt operation.

Round top window

Brighten any room while making a statement with elegant curves.

Single hung window

Traditional fixed-top-sash style with seamless contemporary performance.

Single hung round top window

Single-hung operation with custom character.

Slider window

Bask in wide open views and cooling breezes with smooth horizontal gliding and tilt latch for easy cleaning.

Special shape window

Fixed windows lend architectural interest while inviting natural light.

Numbers only Ultrex can deliver

Why Ultrex

3x
stronger

Built unlike any other

Made with 100% fiberglass strands, our proprietary Ultrex material is 3x stronger than Fibrex^® and 8x stronger than vinyl.

Fibrex^® is a registered trademark of Andersen Corporation.

Outlasts 48K UV hrs

Smooth, lasting finish

Low-maintenance acrylic finish is 3x thicker than all other options, creating a polished look that resists scratching, denting, and fading even after 48,000 hours of sunlight.

17 tons per inch

Extraordinary strength, extraordinary views

Every square inch of Ultrex supports up to 17 U.S. tons, allowing us to expand your views with slimmer profiles.

87% less expansion

Uncompromising climate comfort

Low thermal conductivity paired with specialized glass and a fit that stays true means fewer leaks and improved energy efficiency.

We took an entire wall out in our living room and replaced it with a 16-foot patio door opening out to our deck. We decided to go with Infinity from Marvin because we wanted a fiberglass window in a black exterior and liked the overall look and thin frames."

Jon H.

Ohio Homeowner

Exterior of house with windows lit and a pool in the front featuring Infinity from Marvin windows.

Custom, down to the details

Built to your exact specifications, you can mix and match your chosen window shapes with details like grille and divided lite patterns and elegant hardware in 9 finishes. Available in a multitude of finishes, including proprietary EverWood^® interiors, they are 100% paintable under our warranty.

Explore Options