What are sash windows?

Sash windows are windows that open vertically and have one or more moveable parts.

Commonly associated with traditional architecture and design, they contain two frames – one in front of another. More specifically, this is known as a sliding sash. The window units are positioned in frames with vertical grooves, which allow them to move smoothly and freely without causing frictional wear.

Counterbalances aid the seesaw movement of the sash.

These counterbalances may be exposed inside the window or hidden within the frame. Although these windows do not open on a hinge and do not have outward swings, their ability to tilt aids in cleaning.

What are glazing bars?

Glazing bars are vertical and horizontal wooden pieces that join two or more glass panes adjacent to one another.

This results in a traditional English window effect commonly associated with Edwardian and Georgian Architecture.

Originally, glazing bars were a necessity due to the limitations of the old glass making technology. Windows were made using the traditional glass blowing style.

Here, a cylinder was first blown, then cut and rolled whist very hot. In this technique, only small panes of glass could be made at any time. Larger windows were made from these smaller panes joined together by window bars. Although modern technology allows the production of much larger panes, some people prefer traditional windows.

Modern sliding sash windows are made from single panes, and they replicate the classic look by having window bars laid over them.

Benefits of Sashes

  1. Traditionally charming looks: sashes are undoubtedly lovely and exquisite. Their looks define the traditional 'Olde English' village, and they breathe an air of longevity on a property.

    Sometimes called 'the eyes of the facade,' and they indeed reflect the image of a traditional English village or victorian Christmas card!

  2. Perfect for homes in conservation areas

During renovation works, buildings in conservation areas or those classified as listed may need to install windows in keeping with the original units.

Also called Heritage windows, they are specially crafted to look closely like the building's units ordinarily have. When upgrading properties in conservation areas, special planning permission is required. Local authorities would generally prefer to repair windows rather than replace them.

If repair is not feasible, the authority will have to the window design. Preferably, it would help if you worked with a window manufacturer with experience in the design and installation of authentic replacement heritage windows. They can help get the necessary permission for your project and have a list of heritage window products that have passed the previous application, thereby making your application process easier.

3) Better Ventilation

Due to their ability to open at the top and bottom simultaneously, they provide excellent ventilation. Additionally, the presence of an aperture at the top and bottom regions allow the convection flow of air. This perfectly cools the room during summer, keeps it aerated, and gets rid of dust.

The absence of a hinge also prevents the window from being slammed shut by the wind.

Types of sash windows

There three main types. Your design choice depends on what is most suitable for your home and the period your home was built to emulate.

Georgian windows

Georgian windows are made from two window units containing six glass panes – known as 'six over six.'

Victorian Windows

With the advancement in glass-making technology in the Victorian era, the production of larger sheets of glass became possible.

As a result, Victorian windows have a two over two design. Each window unit has two panes of glass connected by a single vertical glazing bar.

Edwardian Windows

These windows have a six over two design. As the Victorian era passed, the Edwardian era came with more exciting features allowing even Larger windows.

This era emphasized opening up space in buildings. Floor to ceiling windows that will enable as many lights as possible into rooms became common. The lower window unit was made from two panes of glass, and fewer window bars mean more light. The top window unit was made of six panes, like the Georgian style.

This is sometimes called the 'Neo-Georgian' style. The upper windows were also sometimes made of stained or colored glass.

The use of these types of windows declined after the Edwardian era due to the introduction of steel or timber casement windows after the First World war.

Up until the 1930s, sash windows used to be considered to be fashionable. Recently, they have gained more popularity and become the choice of many.

What are they made from?

Initially made purely from wood, sash window frames are made from various materials to fit all tastes, applications, and budgets.

uPVC Windows

Sash uPVC windows are customarily made from painted or colored plastic to look just like a wooden frame. uPVC windows are quite efficient but can not be recycled.

Aluminum windows

Aluminum Windows provide excellent protection, and they are strong and durable.

Although more expensive than the uPVC Sash Windows, they are recyclable and have a longer life span with little to no maintenance cost. Aluminum Windows are commonly seen as being less pleasing to the eye than timber-framed windows

Timber Framed Windows

Timber framed windows can be built using any of the following woods:

Pine: This is cheap and an excellent choice when it comes to aesthetics.

If required for a long term service, it can demand a level of maintenance.

Oak: This is a strong, beautiful, and hard-wearing traditional English material. Oak made windows last longer and provide more security

Red Grandis: Being a south American modern wood, red Grandis is a soft but incredibly hard-wearing wood.

It is durable, relatively maintenance-free, and offers greater security.

Accoya: This is another modern wood found from sustainable sources in New Zealand and treated in the Netherlands. Accoya is carbon neutral. Due to the treatment process, Accoya is superbly strong and resistant to heat expansion or contraction and moisture.

It is a very long-lasting wood erection pills that seniors recommended proves to be applicable even in extreme locations like underwater. Just like Red Grandis, windows made from Accoya are very efficient and secure.

Can sashes have double glazing?

Modern windows have double glazing.

There are different types of double glazing:

Standard double glazing

Standard double glazed windows are more efficient than traditional single glazed windows, having two panes of glass and a sealed cavity.

Slim double glazing

Here, the cavity is filled with an inert gas like krypton or xenon, and the panes have a smaller gap – like 5 – 6mm.

Slim double glazing windows appear more pleasant to the eye and prove to be more efficient than standard double glazed windows.

Vacuum glazing

Following the narrow double glazed windows are the vacuum glazed windows. The cavity between the panes here is a vacuum.

Since there's nothing there, the gap is amazingly small, about 0.06mm. Vacuum glazed windows provide the highest degree of heat and sound efficiency.


The cost of a double glazed sashes depends on the kind of material used, the window size, and how good the manufacture and installation process is.

Cheap softwood double glazed windows may cost about 500 per window. Items with higher quality, longer life span, less cost of maintenance, and higher efficiency and security cost more than others, actually worth the extra fees.

Without a thorough site inspection and survey, most manufacturers wouldn't give quotes nor offer sash windows replacement cost except when all required data are available

Jeff Guest Photo Written by Jeff Guest from an original article on the Gowercroft Joinery blog.

Gowercroft design, manufacture and install award winning heritage windows all across the UK from their workshop in the Mindlands – read the original article here: