Frame Materials

Fiberglass is an ideal material for many products and especially for windows and doors. For all the reasons you are considering replacing your existing windows and doors, FiberFrame designs provide you with lasting performance solutions: strength, durability, air and water tightness, ease of operation, resistance to heat and cold, and low maintenance. The list goes on and on.


Structural Properties

Strength and Durability – Fiberglass window and door frames are the strongest of all common alternative materials: aluminum, wood, and vinyl. This allows for longer lasting performance, elimination of reinforcement, more glass area with larger window openings and slimmer profile’s.



All of FiberFrame’s line of products meet or exceed thermal performance standards set by the US Environmental Protection Agency’s Energy Star Program. Additionally, FiberFrame designs are rated and labeled through the National Fenestration Rating Council, the only uniform, independent rating and labeling system for the energy performance of windows and doors.


FiberFrame fiberglass window and door frames are comparable to glass, and have the lowest rate of expansion and contraction compared to alternative materials. The result is superior weather seal performance over a wide range of seasonal temperature changes, smooth opening and closing operation, and consistent alignment of the sash to frame.


FiberFrame fiberglass is an excellent insulator. Windows and doors made with fiberglass frames use one of the best thermal performing materials available, especially compared to vinyl that often is reinforced with aluminum or steel. Not only is fiberglass longer lasting and more energy efficient, it is environmentally friendly, made from partially recycled material and the plentiful natural resource of silica sand.

air, water, and structural performance

All FiberFrame windows and doors are tested and certified to standards and specifications developed by the American Architectural Manufacturers Association. Comfort Line takes the additional step of participating in NAMI’s certified products labeling system. This label provides you with assurance that the FiberFrame product you select will perform the first time, and for a lifetime.

NFRC Testing Thermal Performance Data

2100 Series Awning
2100 Series Casement
2100 Series Picture
2100 Series Round Top
3000 Series Storefront
5000 Series Patio Door
6500 Series Picture
8000 Series Double Hung
8020 Series Slider

Learn more about fiberglass and why it is better than other window materials.