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Energy efficient replacement window Frames and Spacer Materials

Energy efficient replacement window frames are available in a variety of materials including aluminum, wood, vinyl, and fiberglass. Frames may be primarily composed of one material, or they may be a combination of different materials such as wood clad with vinyl or aluminum-clad wood. Each frame material has its advantages and disadvantages.

Though ideal for strength and customized energy efficient replacement window design, aluminum frames conduct heat and therefore lose heat faster and are prone to condensation. Through anodizing or coating, the corrosion and electro-galvanic deterioration of aluminum frames can be avoided. Additionally, the thermal resistance of aluminum frames can be significantly improved by placing continuous insulating plastic strips between the interior and exterior of the frame.

Wood frames have higher R-values, are not affected by temperature extremes, and do not generally promote condensation. Wood frames do require considerable maintenance in the form of periodic painting or staining. If not properly protected, wood frames can swell, which leads to rot, warping, and sticking.

Vinyl energy efficient replacement window frames, which are made primarily from polyvinyl chloride (PVC), offer many advantages. Available in a wide range of styles and shapes, vinyl frames have moderate to high R-values, are easily customized, are competitively priced, and require very low maintenance. While vinyl frames do not possess the inherent strength of metal or wood, larger-sized energy efficient replacement windows are often strengthened with aluminum or steel reinforcing bars.

Fiberglass frames are relatively new and are not yet widely available. With some of the highest R-values, fiberglass frames are excellent for insulating and will not warp, shrink, swell, rot, or corrode. Unprotected fiberglass does not hold up to the weather and therefore is always painted. Some fiberglass frames are hollow; while others are filled with fiberglass insulation.

Spacers are used to separate multiple panes of glass within the energy efficient replacement windows. Although metal (usually aluminum) spacers are commonly installed to separate glass in multi-pane energy efficient replacement windows, they conduct heat. During cold weather, the thermal resistance around the edge of a energy efficient replacement window is lower than that in the center; thus, heat can escape, and condensation can occur along the edges. To alleviate these problems, one manufacturer has developed a multi-pane energy efficient replacement window using a 1/8-inch-wide (0.32 centimeters-wide) PVC foam separator placed along the edges of the frame. Like other multi-pane energy efficient replacement windows, these use metal spacers for support, but because the foam separator is secured on top of the spacer between the panes, heat loss and condensation are reduced. Several energy efficient replacement window manufacturers now sandwich foam separators, nylon spacers, and insulation materials such as polystyrene and rock wool between the glass inside their energy efficient replacement windows.