Products

Anatomy of an Energy-Efficient Window

ENERGY STAR qualified windows come in a variety of framing materials.

Fiberglass frames are strong, durable, low maintenance, and provide good insulation. Fiberglass frames can be either hollow or filled with foam insulation.
Vinyl frames are low maintenance and provide good thermal insulation. Sections may be hollow or filled with foam insulation. Wide vinyl sills may be reinforced with metal or wood.
Aluminum frames are durable, low maintenance, recyclable, and typically have at least 15% recycled content. Frame design typically includes thermal breaks to reduce conductive heat loss through the metal.
Wood frames are strong, provide good insulation, and are generally favored in historical neighborhoods. The exterior surfaces of many wood windows are clad (or covered) with aluminum or vinyl to reduce maintenance.
Combination frames use different materials separately throughout the frame and sash to provide optimal performance. For example, the exterior half of a frame could be vinyl while the interior half could be wood.
Composite frames are made of various materials that have been blended together through manufacturing processes to create durable, low maintenance, well-insulated windows.

To learn more about efficient window technologies, visit the Efficient Windows Collaborative .