What is a Sash Window? History & Facts

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Experts in Sash Windows Repair & Restoration, Timber Windows & Timber Doors in east midlands

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Sash Windows Refurbish specializes in providing repair and restoration services for wooden windows and doors in the UK, as well as various types of carpentry. During the process of fulfilling orders, we utilize a range of tools and paints, including saws, sprays, primers, resins, and adhesives. With more than 20 years of experience in carpentry, we have tested and used various brands and types of work tools, making us well-equipped to offer helpful advice on selecting the right tools and paints for your needs. Read more ...

If you’re looking to take your home to the next level, consider investing in sash windows.

These traditional frames bring a touch of history and classic craftsmanship to your home. Whether you’re looking for something modern or classic, sash windows come in many different styles to suit any aesthetic. From wood or steel frames to traditional Victorian-style or modern minimalist designs, there’s a sash window out there that complements your look.

But beyond looks, sash windows offer amazing benefits: they’re designed to give you more control over the airflow in and out of your home. They are ultra-durable and easy to maintain, providing years of reliable performance. They offer added security because they actually lock into place with a hook at the top and bottom corners of the frame so intruders can’t force them open.

We’ll explore all these perks – and more – in this article about why you should consider investing in sash windows for your home.

The History of Sash Windows

For centuries sash windows, or box-sliding sash windows, have been a symbol of craftsmanship and architectural heritage. This traditional style is one of the oldest window designs around and has maintained its charm throughout the years.

Sash windows are identified by their iconic design featuring two separate window sashes, which open inside the frame. Besides being esthetically pleasing, sash windows offer several functional benefits for homeowners. They allow air to circulate freely in a room, reducing mould and condensation while regulating temperature and humidity levels. Furthermore, they provide excellent security with their robust frames and locking mechanisms to keep out intruders.

These features make sash windows an excellent choice for many homeowners, allowing them to add a touch of timeless elegance to their homes while also taking advantage of all the practical benefits that come with them.

When Were Sash Windows Invented?

Sash windows have been in use for centuries and their origins can be traced back to the 17th century in England. The exact date of their invention is not well-documented, but they became popular in the late 17th century and were widely used in Georgian and Victorian architecture in the United Kingdom and other parts of Europe.

Sash windows are characterized by movable panels or sashes, that can be slid up and down to open or close the window. Over time, they have evolved in design and construction methods, but their basic concept has remained relatively unchanged since their inception in the 17th century.

What are Sash Windows?

Sash windows are a timeless and beautiful way to refresh any room, offering a unique blend of classic craftsmanship with modern convenience.

The traditional sash window features two large panels of glass held in frames, which can be moved up and down, or slid past each other vertically and horizontally depending on the type of window. This design makes them easy to open while still providing maximum security – something you won’t get with your average double-glazed windows. Plus, they help keep your energy bills low by providing excellent insulation year-round.

TODAY, sash windows come in an extensive variety of styles and materials such as wood, uPVC, aluminium and more. Whichever material you choose though, you can be sure that you will benefit from greater sound insulation from the outside world – making sash windows perfect for urban homes or anywhere that needs a little extra peace and quiet!

Read also: What are Timber Casement Windows?

What are Glazing Bars

It’s time to talk about glazing bars.

Glazing bars are an important part of sash windows, and it’s what you see when looking at the window. They are thin strips of wood, or sometimes metal that divide the glass in a sash window into different-sized parts.

A cross section of typical Glazing Bars

It’s all about esthetics here—historically, the smaller the glazing bars, the more sophisticated and elegant the window looked. And it’s not just a pretty pattern either—glazing bars actually provide extra stability to a window frame by taking some of the load off of the frame itself.

There is one downside to glazing bars though—they can block out some light if you’re not careful. If you choose too many or too thick of glazing bars, you might end up with less natural light entering your space than desired. That’s why it pays to do your research before buying sash windows so you can pick out one that looks great and is also functional.

Benefits of Sash Windows

Sash windows bring back traditional charm, but they also offer great conservation too. By installing sash windows in your home you’ll be making a long-term investment with lots of benefits.

Low maintenance

Another benefit of sash windows is that they are incredibly low maintenance. They don’t require regular repainting like wooden frames do, and their unique design means that it’s easy to clean both sides of the windows from the inside.

Energy efficiency

Sash windows can also help you stay comfortable all year round, no matter what the temperature is outside. Opt for double glazing, and you can maximize energy efficiency while reducing sound pollution and ensuring you feel safe inside your home. The added insulation will even help to lower your energy bills too!

Traditional Charm

Perhaps the most attractive part of sash windows is the traditional and timeless charm they bring to any space. Their classic design, and their panels that slide in a vertical position, can really give any home an archetypal English look and feel.

Offer Great Conservation

When it comes to energy efficiency, sash windows can be a great choice too. With the thoughtful installation of double glazing and draught proofing, they can achieve low U-values — which are key to helping retain heat in your home. That’s right, with sash windows, you can enjoy a warm room temperature while saving money on energy bills.

Moreover, advancements in insulation technology have allowed for timber window frames with low U-values — so it’s easier than ever to find the perfect energy-efficient solution for your property.

Simply put, sash windows offer a combination of classic style and modern energy efficiency; making them an excellent choice if you’re looking to protect your home from the cold winter weather, without compromising its unique atmosphere.

Enhanced security

You don’t have to worry about intruders either — modern sash windows feature state-of-the-art security technology, so you can rest easy knowing that your property is safe and secure at all times. And if you decide to invest in a specialist version like Sash Window Authority’s secret sash window range, then added ventilation can be achieved without compromising on safety either!

Types of Sash Windows

When it comes to sash windows, there are two main types: Georgian and Victorian. While both types bring timeless elegance and classic charm to homes, there are subtle differences between them.

Georgian Sash Windows

Georgian sash windows were typically made of timber and featured two large vertical sashes that slide up and down. The bottom window is fixed in place while the top one can be opened for ventilation. The frames usually have a thick milled border with moulded corners that give them a traditional look.

Victorian Sash Windows

Victorian sash windows are typically made of UPVC or timber and feature a pair of large, rectangular sashes joined together by cords and weights known as pulleys. They have slender frames with slim lines, which creates an elegant look that complements any home’s style. The top sash can be opened for ventilation while the bottom one stays fixed in place.

What are Sash Windows Frame Made From

No matter what you opt for, sash window frames come in a variety of materials. Each material has advantages and disadvantages. Let’s look at some of the more popular ones.

uPVC Sash Windows

uPVC windows (unplasticized polyvinyl chloride) are a great choice if you need windows with excellent insulating properties, low maintenance requirements, and reasonable prices. It’s also available in a range of colours to suit any interior style. The only downside is that it can be prone to fading over time.

Aluminum Sash Windows

Aluminium is an incredibly strong and lightweight material that won’t rot or require repainting like wood does—in fact, all it needs is occasional cleaning. However, aluminium isn’t as thermally efficient as uPVC and is generally more expensive.

Wooden Sash Windows

Timber sash windows offer the best insulative qualities and are the most esthetically pleasing option—perfect for period homes or if you’re after a certain traditional look. The downside? They need regular maintenance to keep them looking their best, with painting every couple of years to protect them from moisture damage.

Double-Glazed Sash Windows

Did you know that sash windows come in double-glazing options? Not only is double glazing great at keeping noise out, but it’s also great at keeping the cold air out and the warm air in. Sure, single-glazed sash windows are beautiful, but double-glazing makes them even better.

Standard Double Glazing

When you choose standard double glazing for your sash windows, you get two pieces of glass with an air gap between them that can be filled with argon gas for extra insulation. Plus, these pieces of glass are sealed together to make sure hot and cold air doesn’t escape through any cracks or gaps.

Slim Double Glazing

If you’re looking for superior insulation without compromising on style, then you should consider slim double glazing. This type of double glazing has two panes of glass with a narrow 20mm gap between them and more argon gas to keep your home warm and cosy. And don’t worry, because this type of glazing won’t add too much bulk or change the look of your windows.

Read also: Secondary Glazing Sash Windows

Sash Windows Cost

You may be wondering, how much do sash windows cost?

The cost of your sash window project will depend on a number of factors, from the size and style of the window to any additional features you add. Generally speaking, a full-size sash window costs between £400 to £800 per side, depending on the materials and hardware used. For larger projects and custom specifications, you may want to consider hiring a professional sash window installer who can provide a tailored quote for your property.

When budgeting for your new windows, also take into account any additional costs such as painting or staining if you’re purchasing unfinished frames. Also, factor in the potential savings you’ll make by replacing your old windows with new energy-efficient models – these can help reduce your energy bills and keep your home comfortable all year round while adding value to your property.


Sash windows appear to be making a comeback and for good reason. Not only are they esthetically pleasing, but they provide a range of advantages in terms of energy efficiency, security, and sound insulation. They are also cost-effective, as they last longer than most other window designs.

Overall, sash windows are the perfect choice if you want to add a classic, traditional look and feel to your home. With the right materials and installation process, they can not only make your home look more beautiful but also contribute to your comfort and reduce energy costs. So, if you are looking for something different and special, consider adding sash windows to your home.

About the author

Glen Ramsey, who presently holds the positions of customer support and content manager, is a cherished member of the Sash Window Refurbish team. He is in a unique position to provide advice on all questions pertaining to the renovation of historic windows because he has a wealth of experience in all elements of window renovation, dealing with clients regularly and assisting them in choosing the best window-related course of action. He oversees the creation of information for all of our platforms in his capacity as content manager, including web content and other materials. Glen has witnessed the whole gamut of Sash Window Refurbish's window restoration activities, from our work on significant listed Georgian homes to a wide variety of smaller-scale private residential projects.


My technician Andrew replaced all my sash windows that had rotten sills. Accessing the rotten sills was not an easy task. He explained to me what needed to be done in order to fix the problem. He is a great person and I’m happy that he was the one who did the job. He is reliable, tidy, friendly and very professional. I highly recommend him.



I hired Andrew and Alex a while back to repair my damaged sash windows. They were was very considerate and very patient as he did his job. A few days ago, I had another problem with one of my sash lock keys and I called him again to come and fix the problem. I’m very impressed that Liam responded quickly and he not only fixed the problem but he also gave me a spare key. What a great after sales service!

Alan W.


I’m very impressed with the new windows that Andrew installed and also the reconditioning job that he did on other sash windows. The quality of his work is by far more superior than what we got when we hired another company a few years back. We will certainly hire him again if any window work arises

Kelly (Sleaford)


Our decorator referred us to Andrew because some of the work needed a window expert. Andrew together with our decorator did a fantastic job. The work was done efficiently and to the highest standards. Andrew is understanding, committed and very professional. I recommend him without any hesitation.

Steaven Reader


Alex did a great job in fixing windows in our terraced house. The windows were broken, frames damaged and the wood was also rotten. Alex's job was high quality and he did it pretty fast. I was also very impressed that he was considerate of my son’s asthma condition and maintained cleanliness. Top work.



Andrew just recently replaced three sash windows in my Edwardian house. He also repaired and replaced some sills and draught proofed three windows. In addition to that, he also did some carpentry work. What I like the most about Liam is that he did a clean job. He is very professional and always updated me about the timescales and costs. He also did his job with minimal disruptions. I highly recommend him.

Cris M.