Cob is a thick, natural building material similar to adobe and made from clay, straw and other inexpensive raw materials. It can be sculpted and molded into many structures, including full-sized homes. Installing windows in a cob house may require a more creative process than doing so in a traditionally built home, due to the flexibility and holding power of this material.
Skylights - Windows or panels of glass mounted in the roof of a cob house add light without sacrificing privacy. The experts at House Alive! say that skylights can introduce as much as 10 times more light into a room than windows mounted into the walls. Many cob houses feature a traditional style rafter roof that makes installing skylights easy, but with the right planning skylights will work in green roofs and other alternative roofing types. Using skylights as windows also avoids issues with installing window frames in the curved walls used in cob house design for stability and strength.
Salvaged Glass - Almost any piece of glass can be embedded in cob securely, according to Daniel D. Chiras in his book "The Natural House." Salvaged stained glass, sheets of window glass separated from their frames, or diamonds of etched glass make beautiful and unusual windows. Pieces of glass should be embedded in the cob's surface at least ¼ inch from the outside of the wall to ensure no water or air will leak around it. Free-form arrangements of small pieces of colored glass add a decorative touch that is difficult to reproduce in a frame-and-drywall house wall. Whole glass bottles can also be embedded in the wall, if it is thick enough, to add light as well as extra insulation.
South-Facing Windows - No matter what kind of windows you choose, installing them on the south-facing wall of your cob house is a good idea. The USA Today website says that windows that face south capture much of the natural sunlight and warmth available passively, reducing the need for electric lighting and heating. In the summer, when extra heat isn't wanted, solar shades or awnings can be installed on the exterior of the home to block heat without cutting back on the light.
Car Windows - This one-of-a-kind idea comes from the "Cob Builders Handbook" by Becky Bee. Since a variety of objects can be embedded in cob, with the material sealing tightly enough to prevent water from running into the wall, it's possible to embed whole car doors into walls of a sufficient thickness. The crank and window of the door is left exposed and the rest is covered. The windows are cranked open and shut, and screens can be attached to the exterior of the home. The main downside to this unusual window idea is maintenance. If the window cranking mechanism breaks, you'll have to crack open the wall to repair it.