Sash windows are associated with the architecture of the 18th and 19th centuries. They make practical and aesthetically pleasing alternatives to casements, with their large glass panels and graceful proportions.

After years of controversy, experts now believe they were originally invented in Yorkshire. Sash windows were designed to allow a small gap for ventilation without letting in the rain, and were also less prone to rotting and distortion due to their enclosure within a box.

Sash windows offered both practical advantages and a more pleasing style than older window designs, and they were popular in both new buildings and as stylish replacements in existing homes. During the mid 18th century the introduction of the window tax caused many windows to be removed. The Georgian sash window took on the modern double sash form. Glass remained expensive and was marked with large bull’s eye patterns in the center of each pane due to the way it was made. Once larger panels became available the classic six-paned Georgian windows appeared. They became a key part of Regency architecture.

Sash windows continued to be popular during the reign of Queen Victoria, although carved and molded decorations were commonly added to them. Sash windows that are gradated in size, becoming smaller at the top of the building are indicative of the style of this time, as are large bay windows. Four paned sashes often indicate a Victorian style. While the absence of glazing bars was originally a status symbol, many people put in windows that imitated older styles once sheet glass had become cheaper and more commonly used during the late 19th century.

Despite their popularity at the start of the 20th century, sash windows have become less common during the last hundred years, with cheaper, less labor intensive types of window being used instead. Recently people have begun to take an interest in the historic character of their homes, resulting in greater demand for traditional style sash windows. These modern versions are produced with all the latest advances in technology, but retain the traditional style and elegance of older sashes, along with their functional design.