Window frames are available in a variety of materials including aluminum, wood, vinyl, fibrex, and fiberglass. Frames may be primarily composed of one material, or they may be a combination of different materials such as wood and vinyl. Each frame material has its advantages and disadvantages.
Aluminum. These days aluminum is primarily used in commercial applications and rarely for residential. This is because the strength aluminum provides is not needed when dealing with the typical size of a residential window. Aluminum will transfer heat, meaning it will get cold when heat retention is needed during the winter, and will transfer cold when you’re trying to maintain cool air during the summer months. In a commercial situation rigidity is needed for very large windows and aluminum must be used at the expense of energy efficiency.
Wood. Wood produces higher R-values, are unaffected by temperature extremes, and are less prone to condensation, but they require considerable maintenance in the form of periodic painting. If wood frames are not properly protected from moisture, they can warp, crack, and stick.
Vinyl. Vinyl windows are made primarily from polyvinyl chloride (pvc), which offers many advantages. They are available in a wide range of styles and shapes, have moderate to high R-values, are easily customized, are competitively priced, require low maintenance, and mold easily into almost any shape.
Fiberglass. Fiberglass is relatively new and not yet widely available. They have the highest R-values of all frames; thus, they are excellent for insulating and will not warp, shrink, swell, rot, or corrode. Fiberglass frames can be made in a variety of colors and can hold large expanses of glass. Some fiberglass frames are hollow; others are filled with fiberglass insulation.
Fibrex. Fibrex material is a blend of wood fiber and specially formulated thermo-plastic polymer. This unique window material is made from reclaimed wood fiber from the Andersen Window Corporation's 65 acre manufacturing operation in Bayport, Minnesota. Fibrex combines excellent strength, insulation properties and provides low maintence.