Fiberglass Windows
Why Choose Fiberglass Windows?
When it comes to selecting windows for your Chicago or Madison home, durability, energy efficiency, and aesthetic appeal are the three main factors that should influence your decision. Fiberglass windows excel in all these areas, making them an increasingly popular choice among homeowners and contractors alike. At NEXT Door & Window, we’re proud to offer top-quality fiberglass windows that combine strength with beauty and performance.
Fiberglass windows are engineered to withstand the harshest elements while maintaining their structural integrity for years. Made from glass fibers and resin, fiberglass windows offer superior strength-to-weight ratio, minimal expansion and contraction, and excellent insulation properties. Whether you’re building a new home or replacing your existing windows, fiberglass provides a range of benefits, making it a smart investment for any property.
Some key advantages of a fiberglass window replacement include:
- Exceptional durability and strength
- Superior energy efficiency
- Minimal maintenance requirements
- Unobstructed views
- Sleek, modern appearance
Check Out Our Recent Fiberglass Window Installations

Fiberglass Window Product Lines
NEXT Door & Window is proud to partner with Marvin Windows, giving homeowners across the Midwest access to Infinity from Marvin fiberglass windows. Constructed with Ultrex fiberglass, Infinity from Marvin windows are developed to be 8 times stronger than vinyl and easier to maintain than wood while resisting warping in harsh weather conditions.. They feature a fade-resistant acrylic finish that’s thicker than most manufacturers’, making them resistant to chipping, peeling, and denting.
Get Bigger Views With Fiberglass Windows
Because Ultrex fiberglass is so strong, Infinity window frames can be built with narrower frames. This means less material for unobstructed views. Enjoy the scenery from your home with Ultrex fiberglass windows manufactured by Infinity from Marvin.
Fiberglass Material Strength
At 8x the strength of vinyl, Ultrex is the strongest window framing material on the fiberglass window replacement market. Unlike vinyl, which can warp and shift under certain conditions, Ultrex is resistant to expanding and contracting in any climate. Furthermore, Ultrex fiberglass captures the nuanced aesthetic of wood without its required maintenance and care. This means Ultrex fiberglass windows are easy to clean without sacrificing style.
Fiberglass Energy Efficiency
While vinyl expands at a higher rate than glass, Ultrex expands at a slightly lower rate than glass. This means Infinity windows are resistant to leaks, seal failures, and stress cracks that can compromise energy efficiency and overall performance.
We submit Infinity windows and doors for independent testing and verification to achieve energy certification and labeling in programs administered by the National Fenestration Rating Council (NFRC) and ENERGY STAR®. Use the NFRC label or speak with one of our window replacement experts to compare energy performance factors across products and brands.
match your home’s décor. Choose from round-top, French casement, push-out, or in-swing designs that can be customized to meet precise size and shape requirements.
Get Started by Talking to an Expert
Want to enjoy new fiberglass windows in your home today? At NEXT Door & Window, we’ve built up a team of experienced window replacement specialists throughout the Chicagoland and Madison areas who are ready to guide you through every step of the process. Our experts are here to provide personalized advice, answer your questions, take measurements, prepare accurate quotes, and help you place your order. They’ll also assist in coordinating the installation process to ensure a smooth and hassle-free experience.
NEXT Door & Window is well-versed in fiberglass window installation. Our technicians regularly undergo training to stay updated on the latest innovations and technologies in the industry. From evaluating your current windows to helping you select the perfect NEXT fiberglass windows and overseeing proper installation, our certified experts are committed to your satisfaction.
See What Your Neighbors Are Saying
After a brief discussion we were presented with several options to meet our criteria. Our sales representative was thorough and patient.
Communications between the purchase and installation was excellent, preempting any need to call for a status.
Installation day was efficient and well organized. The team was professional and showed a high regard for our property,
Net message a quality product installed in a quality fashion.



Sales: Zach Tobin was my salesman and he’s a very good salesman. He knows how to do his job and he knows the product. We purchased 12 Marvin fiberglass windows, Provia front door, and a storm door. Yes, he did his job. Products are pricey, but obviously, we agreed to it.
Process up until installation: We had a few other projects going on so we had to wait for the windows to be done. After signing the contracts you get to hear from your project manager and another individual who handles contracts. I assume it’s standard procedure. Didn’t really receive any phone calls, but rather just emails.
Installation: We had our windows installed in February. Unfortunately, that is the time one of our windows needed to go in because of remodeling the inside. I really didn’t want my house opened up to install all 11 windows when it was so cold but, unfortunately, Next stated they had to do it the same day. The installation crew (Greg and his team) arrived on time and were professional and courteous. They definitely knew what they were doing. My only complaint with this installation crew was they took out two windows and then went to lunch before reinstalling. It was about 20° outside. I mean, that is a first world problem considering I have a furnace; they were probably freezing and really hungry. Other than that, I really appreciated their expertise, thoroughness, and professionalism. Fortunately, they were weren’t able to get it to all the windows in one day so they had to come back at a later date to finish installation. They finished the installation of all the windows within 30 days of starting. Fred installed our storm door-he is FABULOUS as well.
Post Installation: I am writing this review and it is September. As stated above, the windows were installed in February. Due to quality issues, we had to have some sashes and frames replaced. In fact, the job is still not done. Still waiting on a few parts to be installed. The customer service post installation has been more than challenging. I send emails, for documentation, which go unanswered. When I speak with someone at Next, I have to explain my situation over again; kind of like they never received the emails. I stopped hearing from my project manager approximately two months ago, and to be honest, I think I only spoke with him on the phone once during this whole process. The lady I hear from the most, Kim, has a tendency to speak over you and doesn’t let you finish what you’re saying. An example of poor customer service with Kim was when we were discussing the pins that hold the window screens in place. These pins keep breaking and I requested additional ones. She requested to know how many I needed and I told her 10, which would be for five windows. She proceeded to tell me that my Warranty is up and I may have to pay for that. I questioned how my warranty is up and she said you’re no longer under warranty for customer service calls. I explained that the push pins are a part and requested the technician bring them when they finish up with the window parts. Not sure if I’m gonna be charged for those yet. However, I did comment on how poorly made the pins are that keep the window screen in place. Kim proceeded to say that’s a Marvin issue and not a Next issue. I was kind of flabbergasted and did tell her “it’s interesting Next stands behind a poor quality product”. She interrupted me to state Next has nothing to do with the pin quality ( she obviously didn’t get the correlation). I then interrupted her and said there’s no need to argue and requested her to follow up with me regarding finishing the windows. Definitely in need a better customer service.
Overview:
Contract signed in late 2024
Installation of windows in February 2025
It is now September and I’m still waiting on finishing the windows due to parts needed.
Would I do it again with Next? No (even though the installation crew was absolutely fabulous)
The installation went very smoothly. The windows were ready at the projected time, scheduling was flexible, and the install itself took ½ day. Cleanup was thorough, and the installers were respectful to us and our home. No stress.
The windows look beautiful, the quality is great, and we are satisfied with the value. We do realize that we need to see how the windows manage seasonal changes.
We dealt primarily with Ron, who co-owns Next Door & Window with his son. Ron is an expert in the window and door business, and the kind of salesperson you hope you get to work with. He was always striving to ensure we were completely satisfied.
It was a pleasure doing business with Next Door & Window.
The installation went very smoothly. The windows were ready at the projected time, scheduling was flexible, and the install itself took ½ day. Cleanup was thorough, and the installers were respectful to us and our home. No stress.
The windows look beautiful, the quality is great, and we are satisfied with the value. We do realize that we need to see how the windows manage seasonal changes.
We dealt primarily with Ron, who co-owns Next Door & Window with his son. Ron is an expert in the window and door business, and the kind of salesperson you hope you get to work with. He was always striving to ensure we were completely satisfied.
It was a pleasure doing business with Next Door & Window.
We absolutely love our new door!
We absolutely love our new door!
Two weeks ago we had Next replace all of the windows. Again, the windows are gorgeous, the installation was flawless and looks beautiful inside and outside. It has definitely improved our curb appeal and the house just looks brighter and sunnier inside. In the current summer heat, we've also already noticed that house feels like its significantly cooler to the insulation and the windows themselves.
Everyone we've worked with at Next has been wonderful. The installation teams were courteous and very professional. They also left our home spotless. When they finished the work you couldn't even tell they were there. The management team also cares--they checked with us multiple times to make sure everything was right.
Next Door and Window is highly recommended! I've recommended them to my family, friends and neighbors.
John
Selections to Discuss with Your Expert
Our NEXT Door & Window experts are ready to guide you through the key decisions that will make your fiberglass window replacement project a success. Here are some important aspects to consider and discuss together:
Window Styles
Start by evaluating your current windows. Are you satisfied with their style and functionality, or are you looking for a change? Our experts can help you explore various window styles for your fiberglass replacement that complement your home’s architecture and meet your specific needs — from classic double-hung to sleek casement windows.

Fiberglass Options
Perhaps you’ve already chosen fiberglass for its superior qualities. There are still options to consider within this material category. Our experts can explain the specific benefits of our fiberglass offerings, including durability, energy efficiency, and aesthetic features that set them apart.

Divided Lites
Also known as grids or grilles, divided lites can add character and style to your windows. Our experts can show you a range of patterns — from traditional to contemporary — or help you design a custom look that’s uniquely yours.

Colors and Finishes
Fiberglass windows offer versatility in color options. Our experts can guide you through our curated selection of interior and exterior colors and finishes, ensuring your new windows perfectly complement your home’s style, both inside and out.

Energy Efficiency Features
Discuss the various energy-efficient options available, such as low-E glass coatings, gas fills, and multi-pane configurations, to maximize your home’s comfort and energy savings.

Hardware and Accessories
From locks and handles to screens, our experts can help you choose the right hardware and accessories to enhance both the functionality and appearance of your new fiberglass windows.

By discussing these key aspects with our NEXT Door & Window experts, you’ll be ready to make informed decisions. The result? Beautiful, efficient, and long-lasting fiberglass windows for your home.
Your neighbors trust us
Our satisfied customers say it best and keep coming back. Over 50% of our business comes from referrals and returning customers like you.

Gave us great suggestions on window replacements. We love the picture windows and other suggestions he made. He is very knowledgeable and came to our house during the installation to make sure all was going well and we were happy with the windows and installation.
The installers were very skilled and knowledgeable. In my Family Room, the installer even took it upon himself to level the wood shelf under the window he was installing so the wood framing the window would be even and “look nice“ as he said. He didn’t have to put in that extra effort, but he did…he took great pride in his work.
Next Door & Window worked within my schedule and timelines. They are very professional. And Scott the salesperson inspected the installers work to make sure they were doing what they were supposed to. I have nothing bad to say about them.
Very professional, I enjoyed visiting the showroom and being showed around the shop to see how they prepare the windows for installation, and of course meeting those who run the show!
FAQ's
Are fiberglass windows better than vinyl?
How long do fiberglass windows last?
What is the most energy-efficient window?
Upgrade Your Home with New Fiberglass Windows from NEXT Door & Window
Fiberglass windows offer an unbeatable combination of strength, energy efficiency, and style. By choosing NEXT Door & Window for your fiberglass window installation, you’re making a long-term investment in your home’s value by upgrading its overall quality and durability. Our partnership with Marvin Windows ensures that you’ll receive the industry’s best products backed by expert installation and customer service.
Ready to experience the benefits of fiberglass windows in your home? Schedule your free consultation with a NEXT Door & Window expert today or stop in and see us at one of our showrooms. Our team is ready to guide you through the selection process, answer your questions, and provide a customized solution for your home.
Don’t wait to enhance your home’s comfort, efficiency, and curb appeal. The first step towards beautiful, long-lasting windows is just a click away!