Sash & casement windows

When it comes to period properties, there are two main types of window: Sash windows and casement windows. But what is the difference between a sash window and a casement window, and why have their designs and popularity changed over the years?

Sash window design

Sash windows consist of two glazed panels, or ‘sashes’ that slide vertically with the help of weights and pulleys. One of the main advantages of sash windows over casement windows is that because the w