Fiberglass or Vinyl Windows – Which is Better?

Windows framed with aluminum, aluminum-clad wood, and composite wood are available, but for many homeowners, the choice comes down to either fiberglass or vinyl windows.

The truth is, both options have much to offer, and either can be a good investment. If you’re debating between fiberglass and vinyl for your new construction or replacement windows, learning how they differ can help you make the right decision for your northern Utah home.

Pros and cons of vinyl and fiberglass windows


Of the two materials, vinyl is the less expensive option. Vinyl windows are typically between 10 and 30 percent cheaper to purchase and install than fiberglass.


Fiberglass frames are stronger than vinyl, as they’re reinforced with glass fibers. And while vinyl can warp in heat, fiberglass never warps, so it’s a more durable material.


Fiberglass and vinyl windows can both last for several decades. However, due to its increased durability, the former frame material has an edge in terms of lifespan.


The difference in how fiberglass and vinyl windows look is hard to detect. But, the latter has a join line at the corners, while fiberglass frames have a bit more glass space.

Color Choice

Vinyl frames come in a range of baked-in colors, as do fiberglass frames. That said, the latter material is paintable, which allows for more customized color options.


Fiberglass can fade or peel, and vinyl can warp, but both materials are equally low maintenance. In the event of damage, however, vinyl windows are easier to repair.

Energy Efficiency

Because of their glass fibers, fiberglass windows don’t expand and contract under extreme temperatures. Therefore, they offer slightly better insulation than vinyl.

Noise Insulation

The glass fibers they contain also make fiberglass frames quite good at blocking outside noise. In comparison, sound can travel more easily through vinyl windows.


Fiberglass windows contain a significant amount of recycled glass, while vinyl frames are made from difficult-to-recycle PVC plastic. So, fiberglass is the greener choice.


As vinyl frames are somewhat flexible, which allows for quick and efficient installation. Fiberglass windows are rigid, and installing them is more difficult and time-consuming.

Schedule a Free Window Supplier Consultation

As you can see, both frame materials have advantages and disadvantages. And because both vinyl and fiberglass windows can last for decades, neither is a clear winner.

Our advice? Schedule a free consultation with a reputable local window supplier, like Rocky Mountain Windows & Doors in northern Utah. An experienced professional can help you weigh the pros and cons of every frame material and guide you toward a solution that fits your budget and suits the architectural style of your home.

The Rocky Mountain team has been serving Salt Lake City area homeowners for more than 25 years, and we’re happy to answer questions and offer expert advice. To schedule a free, no-obligation consultation to discuss fiberglass and vinyl windows, contact our Orem, Utah, office today.