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Fiberglass Window FAQ
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Fiberglass Windows FAQ

This fiberglass window FAQ page is designed to answer the most common questions homeowners have when researching window replacement. From durability and energy efficiency to cost, maintenance, and how fiberglass compares to vinyl or wood, you’ll find straightforward, expert-backed explanations to help you make confident decisions.

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Fiberglass Window FAQ's

This FAQ page answers the most common questions homeowners have about window replacement, installation, and performance. If you’re considering new windows, these answers are designed to help you feel informed, confident, and prepared.

What are fiberglass windows made of?

Fiberglass windows are made from reinforced glass fibers bonded with resin. This creates an extremely strong, stable material that resists warping, cracking, and expansion far better than vinyl or wood.

How long do fiberglass windows last?

High-quality fiberglass windows can last 30 years or more with proper installation. Their durability makes them one of the longest-lasting window materials available.

Are fiberglass windows a good choice for window replacement?

Fiberglass windows are an excellent replacement option for homeowners looking for long-term performance, energy efficiency, and modern aesthetics. Their strength and stability make them suitable for a wide variety of home styles and applications.

Are fiberglass windows energy efficient?

Yes. Fiberglass frames have excellent insulating properties and maintain a tight seal over time, helping reduce heat transfer and air leakage. This improves indoor comfort and can lower heating and cooling costs.

How do fiberglass windows compare to vinyl windows?

Fiberglass windows are stronger, more stable in temperature changes, and typically last longer than vinyl. While vinyl may cost less upfront, fiberglass often delivers better long-term value and performance.

How do fiberglass windows compare to wood windows?

Fiberglass windows offer the look of wood without the ongoing maintenance. Unlike wood, fiberglass won’t rot, swell, or require frequent repainting, making it a more durable and low-maintenance alternative.

Are fiberglass windows good for coastal or fluctuating climates?

Yes. Fiberglass is highly resistant to moisture, salt air, and temperature swings, making it an excellent choice for coastal and inland climates where conditions can change throughout the year.

Do fiberglass windows require a lot of maintenance?

No. Fiberglass windows are low maintenance. They don’t need regular repainting and can be cleaned with mild soap and water, saving time and long-term upkeep costs.

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Why Choose Custom Exteriors?

We’ve built a reputation for providing the best possible value on truly custom remodeling solutions that help homeowners fall in love with their homes again. Whether you're looking for window replacement, siding replacement or want new doors, our Pleasanton team is ready to help.

29 years. 30,000+ projects. Same location.

We’ve been at the same address in Pleasanton since 1997. If something goes wrong with your installation three years from now, we’re still here to make it right, with the same name, the same team, and the same accountability to this community.

AAMA Certified & Trained Installers

Our installers are Custom Exteriors employees. They’ve been on our team for years, they’re trained to our standards, and they’re accountable to us,  not to the lowest bidder on a job board. When something needs attention in year three, the same team that installed it is still here.

Diamond Certified Since April 2002

Diamond Certified is a third-party certification based on independent customer satisfaction surveys, not self-reported scores. It’s one of the most credible local trust signals in the California market, and we’ve earned it.

A physical showroom, not a brochure

You cannot accurately judge a window’s weight, a siding panel’s texture, or a door’s finish quality from a photo or a manufacturer’s website. Our showroom at 2142 Rheem Drive in Pleasanton exists so you don’t have to guess. Come see the products before you decide. No commitment, no pressure.

Convenient Financing Options

Make your project more affordable with easy financing options. On approved credit.

18 Months ZERO Payments + ZERO Interest

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4.99% Financing on Approved Credit

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Five-Star Reviews

Read Our Testimonials

"Loved working with Custom Exteriors. Very responsive to inquiries. Precise in their measurements, estimate and timeframe for completion. Highly recommend them."

Brian I.

Tampa, FL

"Custom Exteriors provided a great product and good service in replacing 2 sliding glass doors and 2 other windows in my townhouse.  One was a custom window that required extra work in refitting the plantation shutters to the new window.  Although there were some bumps along the way, Jeff and his foreman Ryan excelled at follow up.  I would recommend Custom Exteriors."

Carole N.

Tampa, FL

"Custom Exteriors did a wonderful job. The installation crew were neat and thorough. My salesman Mark kept me informed about delivery and the windows are beautiful, quiet and warm house.  I’m very pleased."

Susan G.

Tampa, FL

"Kevin one of the owners of Custom Exteriors contacted me the following day and immediately tried to make things right. The first thing, I was impressed about was he took my call without hesitation. Many medium sized business will bounce me around to different people before finally being able to talk to the owner. He was an attentive listener and took to the time understand my needs and wants in an exterior entry door.His communication was top notch, sending me estimates the same day or the following day. He gave me choices in fiberglass doors: ProVia and Therma-Tru, hardware: Trilennium vs Emtek, and single point vs multiple point locks. I just ordered a ProVia doors through Kevin. This surprised both to my husband and me. Before contacting Custom Exteriors, we thought we were going to get a Therma-Tru door, but that totally changed once we the information we needed from Kevin. I get the sense that he truly wants to give customers options and information, but respects the customer's final decision. There is not high pressure sale pitch. Kevin wants customers to be informed and happy with the end product."

Hellen K.

Tampa, FL