Fixed glass windows are also known as picture windows given that they act as a frame to a picture of the outside world for your home. These windows are stationary (do not open in anyway) so they offer no ventilation. They are intended to provide outside light into the home, offer an unobstructed view of outside, complement other windows, and improve the aesthetic of a room. Fixed windows are the least expensive type of window since you save money on hardware, weather-stripping, and the time it takes to assemble movable sashes. Fixed windows are also the most energy efficient because they seal better than all of the operable windows.
Fixed windows come in all different shapes and sizes, and may be paired and grouped in many different configurations. Fixed windows can be put together with other fixed windows, or can be used in conjunction with operable double hung, casement and sliding windows.
Small windows that are put directly above larger windows are called transoms. While transoms do not have to be fixed windows, they often are. Fixed windows can also be attached together with less seperation than having studs between them to create a very open feel. This process is called mulling and the window unit itself is called a mullion unit.
In cases of fire, operable windows can provide escape routes. Fixed windows obviously do not provide that same function. This should be taken into account when planning the placement of windows in your home.