Fort Collins (970) 517-3931
Colorado Springs (719) 270-4494

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Infinity From Marvin Windows


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Windows with more than a view. Infinity from Marvin designs windows for unprecedented performance and exceptional aesthetics backed up with advanced building materials and design details that endure the test of time.

Moreover, Infinity partners with local experts who simplify the replacement process for you every step of the way. Because some decisions should only be made once.

nex-gen windows and doors infinity from marvin replacement windows
Product ComparisonInfinity (Ultrex)Anderson (Fibrex)Pella (Duracast)Vinyl Competitor
Thin Frame Profile
Product WarrantyLifetime20 YearsLifetimeVaries
Installation WarrantyLifetime2 Years2 YearsVaries
Stainable Interior
Impact ResistanceGreatGoodGoodPoor


1. Expert Consultation

A Nex-Gen Windows & Doors expert will provide a complete consultation to determine your specific needs — including climate considerations and other factors. They will answer all of your questions and provide a detailed, custom project quote based on your specifications.

2. A Perfect Fit

We’ll review your order, measure your openings and verify your installation needs. Your windows will then be built to your exact needs and measurements.

3. Seamless Installation

We’ll remove and dispose of your old windows, and replace them with your custom Infinity windows.

4. Built for Life®

From our Limited Lifetime Warranty to unparalleled customer service, we go above and beyond to ensure your windows provide a lifetime of optimal performance.


When a job is done right the first time, it is remembered by clients – which is why at Nex-Gen Windows & Doors we send our professional installers to make sure each home window replacement project is completed correctly the first time.

We strive for quality over quantity and constantly raise the bar in the replacement window industry. We live by the code: A product is only as good as the installation behind it.


According to HomeAdvisor, 25% of the costs for heating and cooling your home comes from the energy lost through your windows.

Carefully considering which type of window is right for your home could save you thousands of dollars in energy costs, while increasing the resale value of your home.

Also, independent market studies have noted that 65% of service related issues to prematurely failed windows are related to improper installation. This is due to:

  • short cuts during the installation of new or replacement windows
  • low-cost faulty sealants
  • improper flashing methods
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What are the best replacement windows for my home?

We’re making it easier for you to buy replacement windows and doors by sharing what to expect during your project. Learn more about how you can find the best window for your home.


More view for your money

Because Ultrex is so strong, we actually use less of it in Infinity window frames. That means you get more daylight and greater views outside coming through your window, without bulky materials obstructing your view. And we pay attention to the details that matter — like our clean, non-welded, corners that let you make the most of your beautiful view.

Beauty that lasts

Infinity’s proprietary, high-performance, co-extruded finishing process is unlike anything else in the industry. Our thick, even acrylic finish is free of pinholes, striations and imperfections and will resist scratches, fading and chalking to retain its original beauty.

A finish that resists fading

Want long-term color retention in a variety of styles? Ultrex uses an acrylic finish that is paintable, fade-resistant and virtually maintenance-free.

With a finish that’s 3 times thicker than competitive options, Ultrex resists chipping, denting or peeling.

How Ultrex® Fiberglass Measures Up

We created Ultrex® with one goal in mind: develop the most durable window material in the industry. It’s not only 8 times stronger than vinyl — it resists expanding and contracting in any climate. So you get a tight, snug fit that will last.

Ultrex vs. Vinyl Windows

Vinyl can warp and shift under everyday conditions — potentially making vinyl windows difficult to open and close and affecting their all-around performance. Ultrex resists sticking, swelling and warping so Infinity windows and doors will continue to easily open and close.

Ultrex vs. Wood

Windows Wood windows offer classic beauty that, depending on the environment, can require maintenance and care. Infinity windows capture the beautiful details and profiles of wood — without the maintenance.

Ultrex Expands 87% LESS Than Vinyl

Ultrex fiberglass expands at virtually the same rate as glass, so our windows stay tight and true. This makes Infinity windows resistant to leaks, seal failures and stress cracks that can compromise energy efficiency and long-term performance.

Ultrex is 8x STRONGER than vinyl

Ultrex offers superior bend and flex resistance to protect the integrity of your home.

Ultrex is stable like the glass in your window

Vinyl expands at a much higher rate than glass which may compromise your window’s performance.


Extremely thin coatings of special low emissivity (Low E) metallic material are applied to glass panes to boost their energy efficiency and block out UV rays. Since glass choice plays a big factor in window and door efficiency, your local Infinity partner can provide recommendations on the best selection for your home.

Low E1

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

Low E2

By reflecting heat back to its source, Low E2 offers year-round performance in moderate climates. Low E2 will help retain heat in your home during the winter and keep heat out during the summer.

Low E3

Low E3 is formulated to reject solar heat while letting light in, resulting in increased performance in climates with intense sun exposure.

Low E3/ERS

With an extra metallic layer on the room-side glass to reflect escaping heat back into the room, Low E3/ERS provides maximum efficiency year round in all conditions.


We chose Next-Gen to replace 13 windows in July. We were extremely happy with the results.We liked their low key sales approach, price (very competitive) and results.

Next-Gen was able to exactly match the wood stain color. We also like the screens as they are almost invisible.

Richard N.

So happy with our new windows throughout our home. Ted was very knowledgeable in helping us determine what type of window would be best.

We were very pleased with the installation process led by Rick. Installation team was considerate about not making a mess and cleaning up. We love our new windows and is was great working with the staff at Nex- Gen. They ROCK!

Greg S.

Excellent service and quality product. Ted, Brent and Rick were an amazing team. They were courteous, knowlegable, and did a truly professional job from start to finish.

Our installer, Rick arrived on time, got right to work, and kept us updated on the progress of the installation throughout the day. He cleaned up at the end of the day and left no mess behind. 5 star product, 5 star service.

Diana A.

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Quality Since 1913

Since 1913, the Marvin family has been building quality windows and doors both nationally and internationally.
Their values of professionalism are why they are one of the largest windows and doors manufacturer in existence today.

Their vision to service the replacement window and door markets lead to the creation of
Marvin Infinity windows and doors – which are designed specifically for the home window and door replacements.

When the opportunity came about, Marvin knew they had many options of which material
to use in the window line which came the development of Ultrex® Fiberglass.

Today Ultrex® has established a flawless track record for over two decades in production
and proves to be the window material of the future.


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“Serving Northern Colorado From Fort Collins to Denver, Estes Park to Greeley – We’re here for you.”

Improving your home, Windows, Doors, Siding Installation