The Battle of Window Frames: Fiberglass vs. Composite

Fiberglass and composite are two of the most popular window frame materials. When comparing fiberglass and composite windows, you need to consider several factors, including cost, style, durability and energy efficiency.

The Battle of Window Frames: Fiberglass vs. Composite

Durability and Strength

Both materials provide good durability and strength. They are tied when it comes to long-term durability. Fiberglass though gets the nod over composites in strength. Fiberglass window frames have uniform expansion and contraction even in extreme temperatures, so they don’t warp or crack.


Both window materials are more expensive than vinyl, but cheaper than wood frames. Fiberglass windows are more expensive than vinyl, while the price of composites depends on the manufacturer. Composite frames from reputable brands are more expensive than even the highest-end fiberglass frame. When making a choice, discuss your options with your window contractors and roofers.


Fiberglass windows can be made to look like vinyl, but with thinner frames due to their strength. You can repaint and change their color scheme every few years. Composite windows are available in a wide range of styles and can even mimic the look of real wood.

Energy Efficiency

Fiberglass is the best in energy efficiency and is better than vinyl and composites as well. Composites can be made from a combination of plastics, glass and wood fibers. As a result, the energy efficiency of a composite frame depends on the materials it’s made of.

The Final Analysis

Fiberglass is better than vinyl in price and performs well in most climates. Composites are quite new, so it’s hard to generalize their performance, look and cost. In the end, how they look and work in your home will all depend on the manufacturer and model type.

Window Builders is your most trusted company for roofing, windows, gutters and siding. We provide true value for your money. We’re always ready to serve homeowners in Silver Spring, Rockville and Annapolis, MD. Give us a call at (301) 329-8295.

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