Both fiberglass and vinyl windows have been available for quite some time, but recent advancements in fiberglass windows have enhanced their strength, durability, and efficiency. Although fiberglass windows are generally more expensive, their superior durability is increasingly making them a popular choice over high-end vinyl. When deciding between fiberglass vs vinyl window options, it’s important to note that fiberglass windows generally come with a higher price tag.

Vinyl windows are made from polyvinyl chloride (PVC) and often have an inner structure that includes metal. In contrast, fiberglass windows are crafted from polyester resins activated by a catalyst, pulled through a heated die, and combined with glass mats or strands. This process creates a lightweight, strong material also used in products like skis and furniture.

When comparing fiberglass and vinyl windows, several factors should be considered to determine the right material for your home. These include:

Strength and Durability

Fiberglass is up to eight times stronger than vinyl, allowing it to last significantly longer with proper care. This superior strength is due to its composition. While both frames are made of plastic, fiberglass frames are reinforced with glass fibers, adding considerable strength. This allows for thinner frames with more glass. Unlike vinyl, fiberglass does not weaken in the sun and does not expand or contract with heat. Vinyl can begin to melt at temperatures over 165 degrees, causing distortion and warping on extremely hot days. In contrast, fiberglass maintains its integrity even in high temperatures.

Maintenance and Care

Both vinyl and fiberglass windows are low maintenance. Unlike wood windows, which require regular resealing, repainting, and patching, vinyl and fiberglass windows are relatively hands-off, needing only an occasional hosing off to remove dirt or debris.

However, fiberglass and vinyl windows still benefit from occasional maintenance. Fiberglass windows may need periodic repainting, and vinyl windows might require caulking if temperature changes cause the seal to break.

Fiberglass windows are up to eight times stronger than vinyl due to their reinforced glass fiber frames. With proper care, fiberglass windows can last 50 years or more, while vinyl windows can last up to 30 years.

Installation

Vinyl is a flexible material that expands and contracts easily. This flexibility, along with the ability to produce frames within ⅛-inch of the window size, allows vinyl windows to be installed much faster and more efficiently than fiberglass windows. In contrast, fiberglass is rigid and does not expand or contract as much, making it more difficult to fit into the window opening and taking more time to install.

While professional installation is recommended for both types of windows, some vinyl windows can be installed as a DIY project, but fiberglass windows should not. Additionally, fiberglass windows may take longer to arrive due to the limited number of manufacturers and contractors that keep them in stock, resulting in a longer lead time.

Energy efficiency

The glass fibers in a fiberglass window frame prevent the material from expanding and contracting, and they do not conduct heat or cold. This makes fiberglass a better insulator than vinyl. The same fiberglass used in attic insulation is already in the frame, enhancing the frame’s energy efficiency. As a result, fiberglass windows are up to 15% better at insulating than vinyl windows.

Noise Insulation

The same glass fibers that enhance the energy insulation of fiberglass window frames also improve their noise insulation. Fiberglass is one of the best materials for noise insulation available. In contrast, vinyl does not offer the same insulating properties, allowing outdoor noises to travel through the frame more easily.

Appearance

While the majority of any window is glass, there are a few differences between vinyl and fiberglass frames. From a distance, both appear relatively similar, but up close, vinyl windows have an obvious join line at the corners, whereas fiberglass does not. Fiberglass frames mimic the look of wood windows more closely, while vinyl windows have a plainer appearance.

Fiberglass windows offer more options for style and color because they can be painted, but this also means they may peel, fade, and require maintenance. In contrast, vinyl windows have color embedded throughout the material, so they will not fade or peel and require no maintenance.