Tobias Roberts
Fiberglass Window Frame
Fiberglass has been around for over 80 years and has been used to make strong, durable, and lightweight products such as skis, surfboards, and boats. A fiberglass window frame is made of fiberglass with hollow pockets inside the frame that are typically filled with insulation. The fiberglass used consists of around 60 percent recycled glass.
Look for windows with other energy efficiency features, such as multiple panes, argon-filled and low-e coatings.
The insulating value of windows is usually rated by the whole window U-factor and the lower the value the better. Energy Star rated windows should have a U-factor of 0.27 Btu/hr-sq ft °F or less for Northern climates.
Fibreglass window frames are durable and low maintenance, and can be very energy efficient.
Early window frame materials included wood, iron, and lead. Of those, wood is still used today, and metal frames have graduated to aluminum, stainless steel, and coated steel, with insulation breaks to cut heat loss. Lead is no longer commonly used in window frames.