Different parts of a window

What Are the Different Parts of a Window?

A lot of people look at a window and see two separate parts: a pane of glass and a window frame. Of course, there are actually a lot more parts to a window than that. Depending on the size and style of window, there are many different components working together to create a solid, secure window.

When you’re looking to replace or upgrade your windows, knowing the technical terms for all these window parts will help you make informed decisions. Knowing your window jamb from your window mullion can help you when it comes to buying, choosing styles and asking the right questions during the installation process.

We’ve put together this handy introduction to the different parts of a window, so that when things get technical, you’ll know exactly what’s going on.

What Are the Main Parts of a Window?

Obviously, different styles of windows will have different parts. 

A box sash window relies on a complex mechanism to function and it’s frame will have extra parts to allow for this. On the other hand, a casement window opens on a straightforward hinge. A construction this simple means less parts involved. 

Whatever style of window you have, there are some parts that always feature. The main different parts of window are:

  • Glass
  • Frame
  • Head 
  • Jamb
  • Sash
  • Lintel
  • Sill
Different parts of a window

What Is Window Glass?

You can probably identify the glass in your window. Most windows will feature more than one sheet of glass, either side by side or one above, one below, depending on the style of window. These individual pieces are called ‘window panes’.

Modern windows will always use strengthened glass so they are harder to break. Usually this is tempered or laminated glass, both of which are safer and more secure than standard glass.

These days, they are almost always double glazed to help them keep the heat from your house inside, and the cold air outside.

What Is a Window Frame?

The window frame is another one of those parts you could probably identify without help. Usually made of uPVC, timber or aluminium, this is the name for the outside framework which holds the window in place.

There are also names for each specific part of a basic window frame:

  • Window Head: Almost self-explanatory, the head is the main horizontal part of the frame, located at the very top. 
  • Window Jamb: The technical sounding ‘jamb’ is actually just the vertical sides that make up the outside window frame.

What Is a Window Sash?

A window sash is the inside ‘frame’ which holds one pane of glass. Made of the same material as the frame itself, any handles or mechanisms to work the window are usually attached to the sash.

The sash is easily identified on most windows, because it is the bit that actually moves.

In sash windows, the window sash moves vertically to open the window. In casement windows, the window sash may just be referred to as a ‘casement window’ and it moves outward on hinge to open. 

What Is a Window Lintel?

The lintel of a window is a beam that sits horizontally along the top of the window (above the head of the frame).

Commonly made of wood, steel or concrete, the lintel is a key part of the window construction. This is what supports the brickwork above the window and could also be considered part of the building structure rather than the window. 

In older houses  you can sometimes see the lintel, made of stone or wood. They can be turned into a feature, if they are painted or stained a different colour and look very attractive.

What Is a Window Sill?

The window sill is the part which sits under the window, between the frame and the wall beneath. It’s another part that is structurally important, providing support to the window. 

On the outside of a building, the sill sticks out slightly, often at angle. As well as giving some definition to the appearance of the window, this lets any rainwater run off. It is important to keep water flowing away from the frame and the seals of the windows to prevent water damage.

Extra Parts of a Window

More decorative or complicated window styles may feature extra parts in the sash or frame as part of their ornate design.

Window Grilles/Window Grids

A window grille (also known as a window grid) is a decorative addition which appears to divide a large window pane into smaller panels.

In the past, this grid construction was necessary to build big windows, as it wasn’t possible to create glass that was strong enough to support a larger pane size. They were expensive, so used as a symbol of status in line with fashions of the time.

These days, grilles still feature heavily in period properties. Advances in glass construction means they aren’t structurally necessary any more, so they are often just laid over the top of one big pane of glass as a decorative but non-functional addition.

Transoms and Mullions

Transoms and mullions are used for windows which feature more than one pane or sash. They are parts of the window frame which separate the different panes of glass.

What Is a Window Transom?

If a window has two panes of glass arranged vertically, then the horizontal part of the frame that separates them is called a ‘transom’. 

What Is a Window Mullion?

If a window has two or more panes arranged horizontally, then the vertical part of the window frame that separates them is called a ‘mullion’.

We hope this guide has helped you understand the different parts that make up a window. If you are looking for new windows, we have a great range with many different styles available. From our JELD-WEN brand range to timber and aluminium windows, we have something to suit any property. Just get in touch for more information. 

History of Window Shutters

There are many advantages of window shutters. In this article, we’re going to look at the advantages and disadvantages, and delve into the history of window shutters and their origins.

Window shutters are a common accessory for exterior timber windows. Shutters add character to your home’s exterior while being a great way to prevent direct sunlight from getting into your home.

What are window shutters?

A window shutter is a covering made from aluminium, MDF, and, most commonly, wood. Window coverings are either vertical or horizontal slats that cover the entire exterior of the glass in your window frame.

Advantages and disadvantages of window shutters

Window shutters have many advantages. Aside from preventing direct sunlight from entering your home, shutters also provide heightened security and protect your windows from the elements.

By having the choice of opening or closing your window shutters, you can improve your home’s security by closing them at night. The shutters act as a barrier between your home and the outside world and prevent anyone from looking into your home.

Window shutters also protect your windows. Depending on where you live and the general weather conditions for your area, you may need to install window shutters to prevent damage. Hail and strong winds carrying debris can cause your windows to crack or completely shatter upon impact. Having closed window shutters will remove the chance of this event occurring.

There are a couple of disadvantages that you’ll want to consider if you plan on buying window shutters:

Window shutters drastically reduce your visibility to the outside. Although window shutters are great for making it difficult for prying eyes to see into your home, this also means that shutters obstruct your view, too. If you want a clear view of the land outside of your home, it’s probably best not to go down the route of window shutters.

Window shutters aren’t easy to replace if a slat breaks. Depending on the manufacturer, if a slat breaks, you may have to purchase an entirely new window shutter.

History of window shutters

Image Credit

Window shutters are believed to have first been used in ancient Greece. The Greeks used shutters to prevent sunlight from beaming into their windows, and to provide ventilation during their summer season. After a short time, window shutters were used across the Mediterranean. They were eventually a popular add-on for windows around the world.

At first, window shutters were made from marble and installed internally. It’s believed that the Greeks used this material for its durability. Over time, window shutters’ popularity rose, and they began making the shutters out of wood – like they are today.

The shutters came to England in Tudor times. During this period, glass was considered a luxury, and only the rich had full glass panes in their frames.

When shutters arrived, many people during the Tudor period used them to close off their windows. People without a great deal of money only had glass in the top half of their window, so window shutters were used to close off the bottom half of their frames.

Before shutters arrived in England, lower-class people used wood to close off the bottom half of their windows. Replacing the wooden boards with shutters allowed homeowners to open and close the shutters whenever they pleased, therefore heightening their security while allowing ventilation into their home.

In the eighteenth century, external shutters became popular, specifically in the Victorian era. During this period, walls were thinner, therefore having to reach through the window to close or open the shutters became a more viable option. It also allowed seamless internal space surrounding the window as the shutters would be attached to the external frame of the window – therefore reducing wasted wall space.

Today, a lot of window shutters have been installed for aesthetic purposes. This is because window shutters can now be side-hinged and kept permanently open if the owner desires. This is a great way to add character to your home’s exterior without compromising the view from your window. Shutters look especially great on period properties and look great framing box sash windows or casement windows.

Image credit

Bay window

How Do You Dress a Window?

Dressing a window brings many benefits to your home – they don’t just make it look pretty. Adding curtains or blinds to your window will increase your thermal efficiency and security.

By covering your windows – or having something in place to cover them when you want to – you eliminate draughts coming through your window frame. You also decrease the chance of heat escaping through the glass which decreases your energy bills as you’ll require less heat to warm up your home.

Burglars are opportunists. In most home invasions, the criminal has seen something through a window that they want. By dressing your windows with blinds or curtains, you’re hiding any valuables that may have been on show. This drastically reduces the chances of your home being broken into.

Aside from those 2 major factors, the last reason to dress your window is for decor purposes. This can come in the form of hanging curtains or blinds, but you can also dress your windows by adding a plant to the window sill, or decorating the edge of the frame with fairy lights – this is a great option if you’re on a budget.

Curtains and blinds bring a lot to a room – even though they may get overlooked during the design process.

It’s crucial for curtains and blinds to be measured and fitted correctly. When curtains are too large, your space will look smaller. If they’re too small, they won’t be fulfilling the purposes that made you install them in the first place.

If you want to upgrade your windows, please take a look at our range of high quality and thermal efficient timber windows and aluminium windows.

a bedroom window

What types of window coverings are in style?

The window coverings that are on trend for this year are mainly textured. It seems a lot of us are bringing texture to our interiors in the form of curtains and blinds. Whether that’s a thick set of velvet curtains or a sleek wooden blind.

Modern homes are typically minimal in design – think white walls, silver hardware, and glossy countertops. This is why texture from window coverings work so well. They can be used as colourful statement pieces against a plain backdrop or used to warm up a large open plan area – for warmth, think deep shades of orange wool.

There are many types of window coverings to choose from:

  • Curtains
  • Blinds
  • Shades
  • Linen
  • Velvet
  • Woven wood
  • Silk
  • Wool

Are curtains going out of style?

There are so many choices of curtains out there that them going out of style will never be a thing. Our personal style may change and you may prefer blinds over curtains but there will alway be a need for them. For some people, curtains give them a lot more benefits over blinds.

There are many options for curtains such as colour, design, and texture. Curtains are also easier to cut to size. Blinds are great for understated window dressing, however a lot of people aren’t a fan of their architectural design.

If you’re looking to dress your windows to improve thermal efficiency, curtains are the better choice.

Should I put curtains over blinds?

There is no right or wrong answer to this. Whether you decide to put curtains over your blinds or not is a matter of personal preference.

People often have curtains over blinds to give them more flexibility. Having a blind half open can reduce the amount of light coming in without completely compromising your view to the outside – which is what would happen if you closed your curtains half way. If your blind has slats you’ll still get a bit of light coming through it, even when they’re closed. Remove the light coming through the blinds by installing a set of curtains and closing them in the evening.

There are many ways that you can dress a window, some will want to install blinds or curtains (or both!) and others will want to use items to make the window look pretty.

When dressing your window, consider how much space you have around it, what your budget is, and whether you want to go for blinds or curtains. Think about the design that you currently have in your home, would a sleek set of blinds for your bathroom work better than a lacey curtain? And would curtains for your bay window be cheaper than blinds? Your circumstances are at the heart of your decision for dressing your windows.

Image credit

How To Upcycle Old Windows

We imagine many of you will be revamping your home when spring comes around – DIY jobs are perfect for this time of year.

Typical spring DIY jobs consist of potting plants, repainting internal walls, and clearing out your unworn clothes. However for some, DIY jobs are a little larger than this – installing new hardware, replacing old window frames, and purchasing bifold doors.

If you plan on taking on a bigger DIY project this spring, have you thought about upcycling the item that you’re replacing? In particular, upcycling old windows – there are many ways that you can repurpose your old window frames.

In this guide, we’re going to look at the different ways that you can upcycle your old windows and give them a new purpose.

How do you decorate an old window?

There are many ways that you can decorate an old window if you haven’t got the budget to replace them. Decorating a window doesn’t always mean repainting them – but, it’s a good place to start.

Start by purchasing some good paint – paint especially created for the type of window frame that you have. uPVC, aluminium, and wood, will require different types of paint. Sand away flaking paint and paint the frames with the desired colour.

If you want to decorate your old windows without painting them, there are a few ways that you can jazz them up a bit:

Ideas for repurposing old windows

If your windows are past saving, here are some upcycling ideas that may give you some inspo.

Antique Window Mirror


Remove the old glass from your window frame and sand away flaking paint. Cut and glue mirrored glass to where the glass panes once sat. You can now hang your new mirror on the wall or rest it on an antique side table for a farmhouse feel.

Chalkboard Window

my chalkboard (old window)

Similar idea to the first one, but this time we’re using chalkboard instead of mirrored glass. As before, cut and glue the chalkboard to the window frame. For an easier project, you can cut the chalkboard to the size of the entire mirror instead of cutting it into individual pieces. This is a great way to make something practical from an old window frame.


Window Sideboard

If you have extra wood lying around try your hand at a sideboard. Use the window frame and glass as the sideboard door and add screws to attach it to the rest of the reclaimed wood. Use sandpaper to remove flaking paint and to smooth off the edges. For a rustic vibe, leave the sideboard unpainted.

Jewellery Organiser

After:  A decorative jewelry display / organizer

Insert pins, tiny screws, and hooks to the frame of the window. You can use these to hang jewellery such as necklaces, bracelets, and rings. If you want to go a step further, remove some (or all) of the glass panes and insert a piece of material. You can use this to store your earrings by pushing the bar of the earring through the material.


If you like to keep things simple, you can use your old window for decorative purposes – this adds a great country cottage feel to interiors. All you need to do is make the frame look more presentable. Clean away any dust and dirt, wash the glass panes (or replace them), and if desired, give the frames a lick of paint. You can hang your new upcycled windows wherever you please – they look great in kitchens though!

Upcycling windows is a fun DIY task – think of the self-achievement. There is very little effort required to make something beautiful from an old wooden frame, all you need is a bit of inspiration.

If your DIY task for this year is to install new windows, please take a look through our range of timber windows.

mouldy window frame

What Is the Difference Between Wet Rot and Dry Rot?

Rot is bad news. When this happens to the structural elements of your house, it can spell disaster! But even if it’s just the superficial parts of a door or window that are affected, rot can be a real pain.

You might even have heard that there are different kinds of rot, which manifest in different ways. Don’t worry, we’re not going to delve into the biochemistry here (interesting though it may be); instead, we’re going to look at the practical consequences of rot, and how to avoid them.

What is Wet Rot?

Certain sorts of microscopic fungus will multiply when the moisture levels get high enough. As they spread, they’ll need to eat. And what they eat is the timber in your home. There are many species of fungus that do this, but the most common cause wet rot: they’ll discolour your timber and cause it to fall to bits.

What is Dry Rot?

Certain sorts of fungus have a distinctly different effect on the wood they’re chewing through. Timber infested with dry rot will become brown and crumbly, sometimes so much so that it can be broken into powder between your fingers. Despite what you might assume, dry rot needs a certain amount of moisture to survive – typically around 20%.

Dry rot is rarer than wet rot, though considerably more serious. It will spread away from the source of the damp rather than staying close to it, meaning it could quite literally bring the house down. Don’t delay in treating it!

How to Fix Window Rot

Once you’ve identified the sort of rot you’re dealing with, you can move onto fixing it.

How Do You Fix Wet Rot?

The affected area will need to be stripped out and repaired, blending any replacement timber in with the existing stuff. Of course, this will only prove effective in the long term if the source of the moisture is dealt with.

How Do You Fix Dry Rot?

Timber affected by dry rot should be treated with a suitable fungicide and wood preservative. Badly affected or warped timber should be replaced with a pre-treated substitute. This will lessen the chance of the timber being infected again. Given the serious consequences of a dry-rot infestation running out of control, this is something you’ll want to bring in specialist help for.

How Do You Stop Window Rot?

Prevention, as they say, is better than cure. And so, it’s best to stop rot from occurring before it starts. It’s a good idea to control the ambient moisture level around your timber, and to get damp looked at before it spreads. But if you’re dealing with timber on the outside of your house, such as in a window, this might not be an option. In this instance, look for a lengthy guarantee against rot and fungus when you’re buying the window. Our timber windows ship with a forty-year guarantee against rot and fungus, giving you peace of mind from the moment you install.

Image credit


Do Glass Windows Protect against UV Rays?

Ultraviolet radiation refers to light that is at a higher frequency on the electromagnetic spectrum than the light we can see. It’s notorious for being bad for your skin and eyesight, for being associated with various sorts of cancer, and for causing sunburn.

If you’re shopping for a new window, these are all things which should concern you. Does ultraviolet light pass through glass in the same way that visible light does? And, perhaps more importantly, can you get sunburnt from sitting beside the window? These are the questions we’ll be tackling in this article.

Do UV Rays Go Through Glass?

The answer is a little bit complicated. Not only are there different sorts of glass with different properties, but there are different sorts of UV light, too.

Shorter-wavelength UV-B rays are easily excluded, but longer-wavelength UV-A rays can easily pass through a normal glass window.

If you’re wondering, there is such a thing as UV-C – but these wavelengths tend to get blocked by the atmosphere before they even strike the surface of the planet. So, that’s one less thing to worry about!

Can You Burn Through Windows?

Common glass windows in your car, home, office and in our range will block almost all UV rays that reach the Earth. Glass does struggle with UV-A rays as mentioned before, so whilst you may not feel burning, the UV-A rays can still cause damage to your skin. However, in the UK, you’re going to have to be sat by a sunny window for a long time for that to happen. If you are going to be by a window on a sunny day for hours and your skin is quite sensitive, then some sun block won’t hurt.

Sunburn, moreover, is just one type of skin damage that can result from excess UV exposure; certain sorts of people will be vulnerable to increased freckling and photodermatitis (a skin condition exacerbated by exposure to light).

For an average person in the UK, you really don’t have to worry about burning through your windows on a sunny day. But UV radiation and its effects on the skin aren’t to be ignored. Take care in sunny conditions and always err on the side of caution. Remember also, that you can get sunburnt on a cloudy day.

Of course, some of us deliberately seek out the sun in pursuit of a healthy-looking tan. We’ve covered how windows can contribute to tanning in a previous blog, so be sure to check that out.

Another factor we haven’t considered is that the UK doesn’t receive all that much sunlight – so unless you’re sitting in a conservatory for hours on the south side of a building, you’re unlikely to suffer much. While obviously being true, this fact doesn’t stop UV rays from being damaging. If you’re fortunate enough to work in a greenhouse all day (or unfortunate enough to work at a computer besides a sun-facing window) then it’s important that you aren’t blasé about the damage the sun can inflict. Draw the blinds (or apply some sun lotion) and give yourself peace of mind!

Image credit

Tree in a field on a sunny day

How to Recycle Window Glass

Glass recycling isn’t exactly a new idea. Hopefully you will have been using your local bottle banks for many years now, and recycling all your sauce jars and bottles wherever and whenever you can. But this isn’t the only sort of glass that can be recycled: the stuff in your window is just as amenable to being melted down, reformed, and ultimately reused.

Can You Recycle Window Glass?

There are a few differences between the glass in your windows and the glass that makes bottles. Window glass is treated using a special combination of heat and chemicals. This makes it more difficult to break, and also gives it a higher melting point. Moreover, when it does melt, those chemicals leak out – which if you’re creating new glass products designed for food and drink storage, is a considerable problem.

The long and short of all of this is that window glass can’t be mixed with general glass recycling. It can be either used to make more windows, or it can be ground into a powder and then used as a bulking agent in cement and concrete. This means putting in a special recycling bin. In the developing world, this requires infrastructure which simply isn’t yet in place. In the UK and Europe, however, the story is a little different. A Europe-wide project is currently underway, which aims to make the recycling of this sort of glass economically viable, and thereby spread the practice.

Recycling Glass Windows

So, you might be asking, how do I get rid of old windows? You have several options available, but the most straightforward is locate your nearest recycling centre and make a trip down there.

Where Can You Recycle Glass Windows?

The chances are good that you’ve a suitable glass-recycling facility within a few miles of where you’re now sitting. British Glass provide a useful tool which will help you to locate your nearest. Give them a call before you turn up, and check that they’ll take your window, and that they’re open to non-locals. You might find that you have other recyclable materials at home that can be disposed of on the same trip.

Re-using the glass

On the other hand, you might decide that you can re-use the glass elsewhere in your home. You might be able to extract the glass from your window and turn it into a cabinet, a tabletop, a picture frame, or even outdoor flooring. In the case of the latter, you’re going to be shattering the window into fragments, and leaving it to set on top of setting cement. When the whole thing is set, you can grind the thing down into a smooth, safe surface.

Obviously, this sort of thing is inherently dangerous, and requires that you take adequate precautions. Use protective goggles, gloves, and make sure that you sweep up any fragments or dust when you’re done.

Selling the Window

Of course, most of us will hesitate before going to all of this effort – particularly if we’re not all that creative. But you might find that someone else in your vicinity has a use for your old window, even if you don’t. Making a listing on a site like Gumtree or Facebook is free and may yield results. Perhaps someone needs a new window for their shed, or perhaps there’s a local artist who specialises in glass!


If you’re getting rid of your old windows and looking for new ones, check out our JELD-WEN brand range, our timber window range and aluminium window range. Just get in touch if you have any queries.

timber sash window

How Many Windows Are There in the World?

Over the course of any given day, we’re asked all manner of questions about windows. Some of them come up frequently, and have straightforward answers which we’ve written about on these very pages. But there are other, more difficult window-related questions which can be a little bit trickier.

Candidates in job interviews are sometimes attacked with the age-old ‘how many windows are there in a given area’ question. It’s designed to test your ability to think logically under pressure. It’s also pretty unfair. But we’re not going to leave high-flying job applicants squirming; we’re experts on all things window-related, and so we’ll try to shed some light on the matter.

What do we need to know to work out how many windows there are in the world?

It’s impossible, of course, to give a precise answer to this question. But we can do a little arithmetic based on a few carefully-considered assumptions, and come up with a serviceable estimate.

One factor we have a decent knowledge of is the number of people in the world. We can put this at around 7.7 billion, but for the sake of easy maths we can call it eight. Now all we need to work out is how many windows there are per person, and we’re set.

But we’ve just kicked the can down the road, here, because we’re no way of knowing how many windows there are per person. If you’re living in some parts of the developing world, your house might have just a single window shared between a dozen people. If we say that the average family has four members (ranging from one-person households to those with thirty or more), that means 2 billion households. We might say that the average house has around ten windows, which puts us at twenty billion. Plug in a few more accurate statistics and this figure may rise and fall dramatically, but it’s still a number.

Where things get really messy

Of course, this doesn’t account for government buildings, hotels, swimming pools, hospitals or offices. Nor does it account for the windows which haven’t yet been installed, and sit in factories, warehouses, and in showroom floors. Any what about the windows that have just been taken out and dumped in landfills?

And what about greenhouses? Do they count as one giant window, or several dozen small ones? For that matter, are we just talking about windows attached to buildings, or windows in general? Do car windows count? The average car has six of them – so if your household has two cars, you might have doubled the number of windows per household. And what about buses, trains, boats and aeroplanes, each of which can have hundreds of windows?

But not all glass panels count as windows. Obviously, a pair of eyeglasses should not count towards our estimate. But what about the sides of an aquarium? Is that a window, or is it just a big glass panel through which we look at fish?

Clearly, this is a problem just as much of definitions as it is of maths. So, the answer we’d suggest, if you’ve faced with this fiendish problem, is to say fifty billion. It’s not the right answer, but it is a plausible one. Of course, there may then come follow-up questions. But if you’re sure to mention all of the complicating factors that we’ve mentioned, you may look as though you’ve given the question at least a bit of thought. Besides, some interviewers might just be looking for an admission of ignorance: there is no good answer, and it might be worth fronting up and saying so!

bow window

What Was Used in Windows Before Glass Was Invented?

While the modern window might seem like a pretty simple contraption, it’s actually made from dozens of carefully-engineered parts. Double-glazed windows are able to insulate far better than a single sheet of glass – but even that required hundreds of years of refinement and engineering before it could be made thick and flat enough to actually see through.

Before the earliest forms of glass came to be, a window would be a simple hole in the side of a building, over which could be hung crude animal-skin curtains at night-time. Not terribly comfortable! So how did the modern glass window come about?

When Were Glass Windows Invented?

Glass, as a material, is rare in nature. Usually, it comes in the form of obsidian – which is entirely black. Synthetic glass first came to be widespread in ancient Egypt and Mesopotamia in around 3500 BCE, and came to be used for vases and cups thousands of years after that.

Glass windows, on the other hand, came much later. The ancient Romans used them, sporadically, in the more upmarket villas and government buildings – though their optical qualities were far behind what we might expect today. In certain places, like churches, this difficulty became an opportunity: stained glass windows allowed for the depiction of certain religious scenes. In this setting, transparency didn’t matter.

The earliest forms of window glass were ‘broad sheet’. These were made by first blowing a tube of glass, and then cutting off one side and rolling the whole thing flat.

The difficulty of manufacturing glass windows made them something of a status symbol – and this continued right up to Tudor England, where only the wealthiest households could afford windows of a decent size. In Europe, the Italian renaissance left no aspect of culture or industry untouched. Windows there became taller and sleeker, and separated by mullions and transoms (the wooden crossbeams which run across the surface of a window). As time went by, these elements were made progressively narrower – so that more light could pass through the window.

The Sash Window

The 17th century saw the introduction of an entirely different sort of window: the sash window. This variety of window consisted of two moving panels, which could slide behind one another to create an opening. Windows of this sort needed to be made from ‘crown glass’: a more affordable material created by spinning discs of the stuff, and then cutting those discs into broad sheets.

Modern Windows

Today, our windows are almost universally made from machined ‘float’ glass. This process came about in the mid 19th century, and though it’s been extensively refined since then, the principles used today remain the same: the molten glass is poured into a bath of molten tin. The two materials are immiscible, meaning the sheet floats upon the molten tin as it cools (like oil might float on water). The result is a perfectly smooth sheet on both surfaces, which, after a little bit of extra treatment, becomes perfectly transparent.

If you are looking for quality windows, take a look at our range of JELD-WEN windows and our own timber & aluminium windows. Just get in touch with any queries – we’re happy to help.

uPVC kitchen windows

Standard Window Sizes: Explained

Confused about window sizes and standard window dimensions? Read on and we’ll explain everything you need to know about sizes when shopping for windows.

Do Standard Window Sizes Exist?

First of all, let’s address the fact that ‘standard window sizes’ are actually a myth. There is no industry-wide standard sizing, especially when so many windows are custom-made for houses. Standardisation of window sizes differ between manufacturers, who will make windows in sizes that they deem to be standard. 

As windows and houses are now mass-produced, this has led to an industry-wide standard of sorts, but again, it’s at the discretion of the manufacturers to decide what they think is standard. Those “standards” will also change over time.

Standard House Window Sizes

Before we get into the broad-stroke standard dimensions for house windows, let’s explain how these sizes are specified. There’s a really straightforward system for identifying window sizes. 

Window size is noted in a 4-digit figure. The first two digits refer to width and the other two are for height. For example:

4030 = 4 feet wide and 3 feet high

So, if you want a window that’s 38 inches wide (3ft2) and 68 inches high (5ft8), its size would be noted as 3258. You may need a inches to feet converter (and vice versa)!

This is a handy way of immediately identifying and noting sizes, making it easier for you to shop. 

If you are currently undertaking a project, or want to know the ballpark ranges of common window sizes, then here are some new construction window sizes and average window dimensions:

What’s a Standard Bathroom Window Size?

For this one, we’re going to look at two different standard window sizes. First, standard sliding window size:

Width: 36 to 84 inches

Height: 24 to 60 inches

Standard picture window size:

Width: 24 to 96 inches

Height: 12 to 96 inches

What’s a Standard Kitchen Window Size?

You’re also likely to find picture windows in kitchens – the standard sizes for that is above. Another type of window commonly found in kitchens are double-hung windows:

Width: 24 to 48 inches

Height: 36 to 72 inches

For kitchens, it’s also handy to note standard casement window sizes:

Width: 14 to 35.5 inches

Height: 17 to 73 inches

What’s a Standard Bay Window Size?

Width: 42 to 126 inches

Height: 36 to 78 inches

What’s a Standard Awning Window Size?

Width: 24 to 68 inches

Height: 20 to 42 inches

What’s a Standard Sash Window Size?

Width: 14 to 68 inches

Height: 24 to 128 inches

Things to Consider 

Window sizes are often in whole figures, but generally speaking they’ll be half an inch shorter than the specified number, as this makes installation easier. So don’t worry if your aperture is 37.8 inches high and the replacement window you want is 38 inches high. Double check with the vendor, but it should be still be fine for installation.

If your aperture will not fit a standard sized window, all is not lost. One option is to spend money on custom windows, but if you’re on a budget, this may not be viable. 

The most cost-effective thing to do is adjust the aperture so it will meet standard window sizes. This can’t always be done but if it can, it will certainly be less harsh on your pockets. Custom windows may be necessary in older homes, as they were built before windows were being mass-produced. 

For an outstanding range of JELD WEN windows for your home, buy online today at Windows & More. We have selections of casement windows and sash windows as well as hand made bespoke windows that can cater to all of your needs. We also offer free shipping available to anywhere in mainland UK.