A traditional style of window featuring movable panels, or sashes, that slide vertically or horizontally within the window frame to open and close. They are commonly found in both historic and modern buildings and offer timeless elegance, versatility, and functionality.

Main features of sash windows

• Feature vertical sliding sashes that move up and down within the window frame. Each sash is counterbalanced by weights concealed within the window frame, allowing for smooth and easy operation.

• They typically have a double-hung design, meaning both the upper and lower sashes are movable and can be opened independently or together for ventilation and airflow control.

• Traditionally, sash windows are wooden made from woods such as pine, oak, or mahogany. Modern sash windows may also incorporate other materials such as aluminium, uPVC, or composite materials for improved energy efficiency and low maintenance.

• Sash windows are divided into multiple panes by vertical dividers called ‘muntins’. These dividers give sash windows their distinctive grid-like appearance.

• Counterbalance mechanism: traditional sash windows utilise a counterbalance mechanism consisting of weights and pulleys concealed within the window frame. This mechanism allows the sashes to remain in position when opened and provides smooth operation with minimal effort.

Advantages of sash windows

• Architectural elegance

• Ventilation and airflow

• Space-saving design

• Energy efficiency: modern sash windows feature advanced weatherstripping, insulated glass, and energy-efficient materials to improve thermal performance and reduce heat loss.

• Ease of maintenance: designed for easy maintenance and repair, with removable sashes that allow for convenient cleaning, painting, or replacement of individual components. This reduces the need for extensive maintenance and prolongs the lifespan of the windows.

Disadvantages of sash windows

• Historic preservation: in historic areas, maintaining the original sash windows may be required to comply with preservation guidelines.

• May have security vulnerabilities due to movable panels and traditional hardware. May require additional locks to ensure windows are secure.

• Moisture and rot: wooden sash windows are susceptible to moisture infiltration, which can lead to rot, decay, and structural damage over time.

• Noise reduction: while they provide excellent ventilation, they may also allow for the transmission of external noise into interior spaces.

• Operational smoothness: Over time, sash windows may experience wear and tear, resulting in issues such as sticking, rattling, or difficulty in opening and closing.