What Is a Window Sash?

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A window sash is truly the sum of its parts. If all of the pieces of a window sash were disassembled, it would probably be unrecognizable. Older windows can be disassembled, but newer windows increasingly come with parts that are factory-built and sealed. PVC window frames are welded together. Grilles are sealed behind glass. And the separate sheets of glass are no longer separate; rather, they are built as one unit, called an insulated glass unit (IGU).

What Is a Window Sash?

A window sash is the part of the window that you move up and down when you want to open and close the window. It’s a wooden frame keeping the panes of glass in place.

Glass

Two sheets of glass comprise a double-paned window. Sometimes this is called glazing, as in double-glazed window or triple glazed window. Single-paned windows are less common than in years past, with double-paned windows being more the norm.

Insulated Glass Unit (IGU)

The insulated glass unit is the heart of the modern window. IGU is a window industry term that refers to double- or triple-paned collection of glass, gas, seals, and gaskets. The window frame and peripheral items are not included with an IGU.

Window Frame

Window frame is a convenient term for the wood, fiberglass, vinyl, or metal parts that hold the glass together. In older windows, the window frame is actually composed of rails (horizontal pieces) and stiles (vertical pieces).

Window Grille

Within the window frame may be smaller sections of window that go under different terms but collectively called grillework. Older, single-pane windows may have true mullions, in which panes are separated by wood. Newer double-pane windows may have a mullion look. The industry term for this is GBG or grille-between-glass, in which false mullions are placed between the sheets of glass and serve no structural purpose. GBGs provide aesthetic appeal and allow for easier cleaning of the glass.

Gaskets

Glass must be sealed into the framework. Gaskets made of rubber or TPVs (thermoplastic vulcanizates) serve this purpose.

Argon and krypton are colorless, odorless gasses that are injected between the sheets of gas for its insulating properties. Single-pane windows have no gas. Seals allow for equalization of gas and outside pressure. IGUs come with the gas already inside.

Seals

Because of the difference in pressure between the IGU and the exterior, seals are built into the IGU to equalize pressure.

Double-Hung Windows

Window sashes are typically found in the double-hung window style, in which one sash is positioned above a lower sash. The lower window sash has the capacity to slide up and down until it is nearly parallel with the upper sash.

It is not uncommon in older windows for the upper sash to be fixed in place, while the lower sash remains operable. In this case, it may be referred to as a single-hung window. Newer double-hung windows, though, tend to have upper sashes that move up and down.

One benefit of this action is that it allows for the window to be open, without the hazard of people, namely small children, falling out of the window. An open upper sash is too high for most children to reach.

Fun Fact

Sliding sash windows became prevalent in England after the Great Fire of London, in 1666, when new building regulations stipulated that timber window frames had to be recessed behind stone or brick.

Casement Window Sashes

While mostly associated with double-hung windows, window sashes can be found on any type of window which moves, such as the casement window. Care must be taken with casement windows when they are open. A high wind can move casement window sashes and break them off.

Window Fogging and Leakage

Double-glazed IGUs often come with one problem: fogging. Fogging is the result of improperly installed gaskets or gaskets that have deteriorated over the years. Impaired seals allow gas to escape, greatly impacting the window’s insulating properties. As condensation builds, light and views are obscured.

Window defogging companies can fix this problem by drilling 2mm holes in the glass, injecting cleaning fluids, letting them dry, and then plugging up the holes. Window defogging is not a common practice, since the procedure often does not last for long.

Window Sash Replacement Kits

If the window sash breaks, it is possible to purchase a sash replacement kit. This avoids the cost and mess of total window replacement. Also, because it is designed for homeowners to be able to use, it helps avoid labor costs associated with entire window or individual sash replacement.

The UK’s most authentic uPVC sash windows

Our customers rate us

The highest quality

Every Rose Collection timber-alternative sash window we manufacture has more than 40 years of knowledge, experience and innovation built in. The result is the highest quality suite of sash windows on the market.

Fully bespoke builds

Our sash windows are tailored and built specifically for you. We have a broad range of customisation options, which choices to suit any type of property, from traditional to contemporary.

Options for everyone

There are three models in the Rose Collection; Ultimate Rose, Heritage Rose and Charisma Rose. Between them they offer styles and options to suit every home and budget.

Market Leading Sliding Sash Windows

Combining high-performing modern functionality with the traditional charm and character of an original timber sash window, the Rose Collection is the UK’s premium collection of timber alternative sliding sash windows.

With 40 years of manufacturing experience built in, The Rose Collection has been carefully crafted to give your home the stunning look of authentic sashes while being easy to use and maintain, while offering enhanced security, energy efficiency and noise reduction.

Whether you live in a traditional or contemporary property, Rose Collection sash windows will enhance your home and offer years of trouble free enjoyment. Our timber-alternative vertical sliding windows enhance visuals while keeping your home warm, quiet and secure.

Traditional Design

All our sliding sash windows authentically replicate timber to the highest degree.

Zero maintenance

There is little-to-no upkeep required with any of the Rose Collection windows.

Energy Efficiency

Our sliding sash windows keep your home warm in summer and cool in winter,

Window Security

Modern locks and security features ensure our sliding windows protect your home and family.

Noise insulation

Our timber-alternative windows help make your home a haven from the outside world.

Design Your Sash Window

Creating the perfect sash windows for your home needn’t be a tough task, thanks in part to our easy-to-use online design tools. Letting you tweak and visualise to an exact degree, everything from colour, astragal bar layout, and hardware can be customised to achieve the best result.

TheUltimateRose

The Ultimate Rose is the most authentic and high performance sliding sash window on the market. You won’t find a better product than the Ultimate Rose, which is completely indistinguishable compared with original timber. They are fitted with some of the latest innovations in the entire double glazing industry.
“Quite simply, the UK’s most authentic timber-alternative sash window.”

TheHeritageRose

Even as our middle model, the Heritage Rose comfortably outperforms other sliding sash windows on the market. They authentically replicate the visual effects of timber and offer exemplary standards of thermal efficiency, weatherproofing and home security.
“The quintessential period sash window, updated for the 21st century.”

TheCharismaRose

The Charisma Rose offers competitively priced period looks with a host of modern features. It has all the quality and features you’d expect from a Rose Collection sash window, but at a lower price, helping it stand toe to toe with the leading models of our competitors. They’re best for those in contemporary properties.
“Competitively priced period looks with a host of modern features.”

What Are Sash Windows? Types and Costs

Sash windows are a typical feature of our traditional Georgian, Edwardian and Victorian properties.Thanks to their distinctive design and aesthetics they have become a big part of our architectural heritage, but they are still installed today using modern and highly efficient materials.

What are sash windows?

Sash windows don’t open on a hinge. A traditional ‘sliding sash’ window is usually made up of two sashes that slide up and down (or side to side), one in front and one behind, in vertical grooves, counterbalanced by lead weights on cords. Sliding sash can be opened at the top or bottom, or both. Traditionally, they have no outward swing but modern designs tilt in and out for easy cleaning.

The glazed area consists of a number of smaller panes held together by glazing bars. The number of panes depended on the era. Sash windows for historic properties must be chosen to carefully to ensure you get the right period, as there were several developments and style changes in sash windows over the years.

Benefits of sash windows

Traditional charm

There’s no denying that sash windows are both charming and elegant. Described as the ‘eyes of the façade’, original sash windows have obvious aesthetic attributes. Handcrafted in original timber, they are stylistically in-keeping within the context of a traditional property.

Suited to homes in conservation areas

If living in a conservation area or a listed building restoration or replacement with genuine timber sash windows may be your only choice. Where possible existing sashes should always be repaired and waterproofed. However, if sash windows are beyond repair then many companies manufacture authentic replacements.

Increased ventilation

The sliding panes of sash windows are an excellent choice if ventilation is a priority for you. Two sliding sashes with an opening at the bottom and at the top of the window enables you to create a cooling convection flow which is ideal in summer.

The lack of hinges also means you don’t have to worry about a gust of wind slamming the window shut. Increased ventilation will not only improve your comfort, but also helps to remove dust from the air in your home.

What are double glazed sash windows?

Double glazed sash windows are like traditional sash windows but with the added benefit of double glazing. Particularly during the winter months.

Double glazing is made up of two panes of glass rather than only one. It may sound like a simple idea but choosing double glazing is beneficial for a number of reasons.

• Increased thermal efficiency
• Lower heating bills
• Less outdoor noise making its way into the home
• Fewer draughts
• Less condensation on the inside of the window
• Increased security

Types of sash window

There are 3 main styles of sash window to choose from; your choice will depend on which suits you home’s aesthetics and, potentially, which period it dates from.

Georgian: feature ‘six over six’ panes.

Victorian: feature a ‘two over two’ grid design.

Edwardian: include panes which are ‘six over two’ in design.

Horizontally sliding sash windows are sometimes called ‘Yorkshire Sash’ windows. Either one or two of the panes can slide open.

Frame materials

Traditionally sash window frames would have been made from wood, but today we have a lot more options to choose from.

Sash uPVC windows are often used as a substitute for painted wood. Although it cannot be recycled uPVC is low maintenance and energy efficient and also comes in a wide range of colours and finishes.

Off the shelf, uPVC is the cheapest option for sash windows with timber costing as much as 40% more for the windows alone.

Aluminium

Aluminium frames are more expensive than uPVC, but they are stronger which is better for security and durability. The material is also recyclable and, when compared to wooden frames, needs very little maintenance.

Composite

Composite sash windows are increasing in popularity with wood on the inside and clad with aluminium on the outside. This ensures they keep the classic look of wood internally, but are resistant to weather conditions and require virtually no maintenance externally.

Timber

Wood is very durable and an excellent insulator and if taken care of properly can last longer than the modern uPVC varieties. With the use of modern finishes (available in all colours or stains) timber windows don’t have to be high maintenance.

Cost of double glazed sash windows

The costs of replacing sash windows depends on:

• Age of the property
• Whether you live in a conservation area
• Size of the window
• Style of the frames
• Glazing (double glazed sash windows are a great option as they can help to lower heating bills).

The following table gives some approximate costs for the supply only of sash windows in white uPVC.

Size of Window (mm)	Average Cost Per Window (supply only)
500 x 500	£500 – £600
1000 x 500	£575 – £675
1000 x 1000	£600 – £700
1200 x 1200	£700 – £800

For the same windows in aluminium, it’s likely the cost would increase by around £400 – £500 per window, and wooden windows could cost £400 – £800 more per window. For example, after some industry research we found the following estimated costs, this time including installation.

Frame Material	Average cost per window (including installation)
uPVC	£600 – £1,000
Aluminium	£1,100 – £1,400
Wood	£1,000 – £1,800

Of course, these figures are intended as representations only and not quotes. To get exact prices for sash windows tailored to your home you will need to find quotes from installers near you.

Get free quotes for double glazed sash windows

The final price of your sash windows will be impacted by several factors such as their size, type of glazing and frame material, but will also vary depending on which company you choose to carry out the installation. To find the best deal you need to compare at least 3 quotes to ensure you’re being offered a competitive price.

Complete our enquiry form today and you’ll get free quotes from up to 3 window suppliers working in your area. So you’ll get tailored quotes without the hassle.