Evolution of the Sash Window

The sash window has been the most common window for residences since the 1800s. They are called sash windows because of the movable panels that hold the glass. These frames are called sashes, and are separated from other movable panels by muntin. Although any window with independent frames is a sash, the term sash window usually refers to glazed panels that open vertically. Horizontal sashes are called Yorkshire light sliding sashes. They have the counterweights hidden in a box case. The oldest known examples of a sash window were found in the 1600's in England. Supposedly the English scientist Robert Hooke created the first counterweight window.

Sash windows are a staple of Victorian houses where the classic arrangement has the panes arranged in two 3x2 sashes which comes out to 6 total panels. In the Edwardian and Georgian eras, English suburban houses were built with standardized windows. These windows are hundreds of years old, so they cannot compete with modern windows in terms of stopping drafts. Even the most well built Victorian window is probably so old that it needs help from a Denver windows company. Luckily these standard sizes are 4 feet across, making a replacement window Denver a snap. Handmade units may have been more beautiful, but can come in any size.

One good thing about the old vertical sash windows is the sashes slide vertically throughout the weatherstripping, giving the window a large maximum ventilation area equal to half the total area. Each sash has its own set of springs and balances that will hold the window open at any point.

The counterweight is a heavy metal, usually cast iron or lead, concealed within the window frame. Modern replacement windows Denver have no counterweight, and their springs are housed within the metal frame. The counterweight is connected to the window by a sash cord. Ancient windows have a chain system which runs through a pulley and spring balance system at the top. Some sash windows can be fully opened on the side on hinges. In the US, these kinds of windows refer to double hung windows that have two independent pane assemblies that move up and down. Single hung designs are the same as double hung, except the top sash is stationary. Some exotic window designs typical of northern church steeples have triple and quadruple hung windows.

The frames are made of sealed softwood. Contact a glazer when trying to convert from a single to double hung design. Although these wooden sash windows are beautiful and historic, they have problems with water. Typically they will become damaged over time by rot, swelling and shrinking. This makes them poor insulators. The sliding mechanisms and counter weight cords can fray and cut. High maintenance is offset by easier cleaning because of the mobility of the sashes. These windows are best when open, not closed.