The window frame is the enclosure that holds the main parts of a window—called window sashes—in place. Window sashes may be fixed or operable. Obviously, in a fixed window the sashes don’t move. Operable windows employ several methods for window sash movement. With single- and double-hung windows, the sashes slide up and down. With casement windows, they swing in or out. Sliders slide. And so forth. (For more about various types of windows, see Window Types.)
Window frames and sashes are made from a variety of materials, including wood, aluminum, vinyl, steel, or wood-clad vinyl and aluminum. Each of these materials has its benefits and drawbacks.
Most notable of these is that wood, the traditional and generally preferred material for window frames, is great looking and has good insulation value but is prone to damage from sun and rain. Painting every few years solves this problem but adds to your maintenance requirements.
Metal and vinyl windows are more durable and maintenance-free than wood but not as attractive. Clad windows (wood over metal or vinyl) are an excellent marriage of the best from both worlds but cost a premium. For help with choosing the right window material, see Windows: A Buying Guide.
