uPVC kitchen windows

A Guide to uPVC Windows

In the UK, the majority of window frames are manufactured using uPVC. uPVC windows offer several distinct advantages over windows made from aluminium or timber, the most obvious of which is their affordability.

In this article, we’re going to take a closer look at uPVC windows, and what they can and can’t do. We’ll do this by addressing a few questions about the limitations of uPVC, and discussing which ones can and can’t be overcome.

What is uPVC?

First, let’s establish exactly what we’re talking about. PVC, or poly-vinyl-chloride, is a form of plastic perhaps best known as a substitute for leather. You might have seen tarpaulins, dresses and coats made from the stuff. In this context, the material has been supplemented by a plasticising agent, which is what allows it to become flexible and stretchy.

That’s not the extent of PVC’s powers, however; if an extra ingredient is added, the material sets in a rigid, tough form. This material is known as unplasticised PVC. It’s particularly suited to use as a building material, and it’s the stuff from which most windows in the UK are now built.

Can uPVC Windows be Painted?

The overwhelming majority of uPVC windows are brilliant white, and those that do come in other colours are given their pigment at factory level, before the plastic has set. uPVC is naturally resistant to paint. Their surface is low-friction, which allows them to resist stains, and rainwater to quickly slide away. For the most part, this is an advantage, as it makes cleaning the windows easy, and it gives the surface of the material a durable, glossy appearance. It also makes painting your uPVC window very difficult.

This doesn’t, however, mean that painting a uPVC window is impossible – It just means that any coat of paint you apply will be more prone to peeling and warping over time, as differences in pressure and temperature gradually lift the paint from the surface of the plastic.

For best results, we’d suggest masking the glass thoroughly and applying a spray-on coat of matte paint. If you want a gloss finish of the sort you’d get on a door, then you’ll need access to a heavy-duty paint-sprayer. If you’re going with a gloss paint and a brush, then you should be prepared to apply multiple coats, and sand-down with extremely-fine sandpaper. Be very careful that you don’t sand all the way down into the plastic; once the top layer has been scraped off, you’ll never get it back.

While painting can be a great way to lend a new lease of life to aging uPVC windows, if you’re investing in new windows and aren’t keen on them being white, we’d strongly suggest opting for engineered timber or aluminium windows instead. The material simply isn’t built to be modified in this way, and looks and functions best when left in its usual glossy-white state.

Can uPVC Windows be Recycled?

One of the reasons that uPVC is so affordable is that it can be easily reshaped and recycled. It’s a thermoplastic polymer, which means it’ll melt when exposed to a sufficiently high heat. uPVC windows should therefore be taken to a recycling facility when they reach the end of their lifespan. Find your local recycling centre, and remove any non-uPVC materials, like seals, and metal hinges, from the window.

How Long Do uPVC Windows Last?

uPVC windows can easily last three decades or more. To be assured of the best possible quality, we’d strongly recommend checking the length of the warranty before deciding. If the supplier isn’t prepared to put their money where their mouth is when it comes to longevity, it’s time to start worrying. Look for a warranty of ten years.

Of course, this is assuming that your installation was carried out by an expert under good conditions. If the window is misaligned or otherwise poorly-installed, you can expect it to fail much sooner.

When failures do occur, it’s usually a part of the window that’s not made from uPVC that’s to blame. For example, moving parts like seals and hinges might wear out and become misaligned thanks to frequent stress and gravity. These hardware components can in most cases be replaced while leaving the window itself intact.

Finally, there’s another factor complicating things here, and that’s the improvement of the technology over time. Given that modern windows are far more efficient than those manufactured even just ten years ago, you might consider it worth your while to swap out for some new ones.

Signs of an aging window

If you think your uPVC windows are looking a little sorry for themselves, then you’ll want to keep an eye out for the following.

Condensation occurs between the panes of a double-glazed window when the seal around the edges has broken, and water vapour has been allowed to creep in. The presence of such a gap means that all of the inert gas inside the panel has escaped, which will hugely reduce the efficiency of the window.

Draughts around the window frame can be fixed without replacing the window, but they’re usually evidence that the window is on its last legs. If you find yourself shivering every time winter rolls around, investing in replacement windows might make financial sense.

Discolouration. uPVC windows are white when they’re first installed, but this can change. Prolonged exposure to ultraviolet light can, over time, cause that white to turn yellow, which, amongst other things, will devalue your property. If your home is equipped with old, yellow windows, then a replacement set is probably long overdue.

Can You Drill into uPVC Windows?

Unlike timber, uPVC is not designed to be modified once set. While it’s possible to do so, there are better alternatives. For example, if you need to drill a hole to pass a cable from the outside of the property, it’s almost always better to drill said hole in the surrounding wall than it is through the window frame itself. The same applies if you’re fitting blinds or curtains to your uPVC windows.

uPVC windows are very rarely uPVC all the way through – they often contain metal cores which can make drilling problematic.

What’s more, sealing the edges of the hole once you’re done will be difficult. You’re more likely to compromise the performance of the window than you are to improve it. A gaping hole in your window frame will look amateurish, particularly when you come to sell the house.

But what if you’re looking to replace your uPVC handles? Won’t that require drilling into the window? No, because uPVC handles are not interchangeable, like their counterparts on timber windows. They’re designed to remain in place for the lifespan of the window.

How Can You Maintain uPVC Windows?

To ensure that your windows enjoy the longest possible lifespan, we’d suggest giving them some occasional TLC. We’ve covered how to clean and refresh them in previous blogs, so be sure to give them your attention.

What’s Wrong With uPVC?

As we’ve mentioned, uPVC compares favourably to timber in terms of how much maintenance it requires, but it’s not a perfect material. Amongst its disadvantages is a tendency to expand during periods of hot weather. In extreme cases, this can exacerbate any existing misalignment issues and make it difficult to shut the window. There are a few things you might do to combat this problem, and we’ve covered a few of them here.

Homes in conservation areas are subject to stricter planning controls, which might make installing uPVC windows impossible. For all of their many virtues, uPVC windows will reliably undermine the impression that you’re walking through a 16th-century countryside village. As such, check with your local authority before you place the order – as having to remove your windows a few days after installing them can be embarrassing, not to mention costly.

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An open casement window

How to Repair a Casement Window

The most popular style of window in the UK is the casement window. Unlike its closest rival, the sash window, the casement window opens by swinging outwards on a set of hinges.

This offers several advantages.

For one, casement windows are less complex and easier to maintain than sash windows, and they can be equipped with compressible seals which keep out draughts and can help cut your energy bills.

However, as resilient as casement windows are, problems can occasionally occur. Thankfully, the majority of those problems can be solved without the need to call in a professional. In this article, we’ll look at how to repair casement windows. We’ll examine some common issues, and see how they should best be addressed.

How do you fix a sagging casement window?

Throughout a casement window’s lifespan, it will gradually sag as a result of gravity, and it only takes a few millimetres of drop for the window to begin catching against the frame. If your window is dragging, you need to adjust the hinge channel to compensate. This should be done from the outside. You’ll need to first establish the direction in which your window is sagging, and then move the corresponding hinge.

Step 1.

First, we’re going to remove the arms that make up the hinge at the bottom of the window. Open it and unscrew everything. You’ll then be able to lift out the sash which tethers it to the window frame.

Step 2.

It’s time to fill in the existing holes. Do this with epoxy resin if your windows are uPVC, or wood-filler if they’re timber. Don’t be tempted to skip this step, as you’ll be drilling new holes just a few millimetres from the old ones, and the drill could slip into the old holes. Be sure to rub the filling smooth for the best possible finish.

Step 3.

Now you’re going to drill some new holes using an 1/8” pilot drill. Drill them a couple of millimetres across from the old holes. A little bit of guesswork may be in order here, given that there’s no way to test the window before you’ve secured it to the frame. If you’ve only just noticed the problem, chances are that moving the hinge across a small increment will result in a significant improvement.

How do you clean casement window hinges?

On the other hand, rust accumulating on your gears can cause the window to become stiff and eventually inoperable. Cleaning the gears thoroughly requires a little bit of disassembly – but it’ll help fend off corrosion and keep your window working as it should for longer.

Step 1.

First, we’re going to unclip the operator arm. This usually comes apart from the window via a clip. It’s attached at the other end via a series of screws, which can be removed with the help of a trusty cross-head.

Step 2.

Next it’s time to clean away the grime. Do this over a plastic tub using methylated spirits and an old toothbrush. Scrub until every last bit of grime has been removed.

Step 3.

Before we return the gears to the window, we need to ensure that they’re lubricated and protected from the elements. Apply your lubricant generously and use a soft cloth to distribute it across the entirety of the metal. Work it into the gears by moving them back and forth. When they move easily, you’re ready to reinstall.

Step 4.

Some casement windows are attached to an arm which runs along a track at the bottom of the window. These should be cleaned using a harsh, wire brush and solvents applied to a cloth (which should lift up all of those stray metal particulates).

Make sure you’ve gotten right into the track, and apply a layer of lubricant when you’re done, as just described. Again, you can work the lubricant in by moving the window back and forth.

Now, there are some instances where it’s impossible to repair the hinge, and you’ll need to look at replacing the hinge instead. Replacement hinges for casement windows are widely available and inexpensive.

How do you re-seal a casement window?

The seal around the edge of your window contributes enormously to its energy efficiency. If yours is damaged, then fixing it should be a priority. The stripping might have been pulled away from the corner of the frame, in which case you can address the problem by simply sticking it back into place with a dab of polyurethane sealant. On the other hand, repeated cycles of compression and expansion can, over the years, cause the stripping to lose its elasticity. When this happens, it’s time to replace it.

Step 1.

Pull the strip loose from the window. Do this slowly to minimise the risk of the wedge section of the strip remaining stuck in the grove. Should this happen, you’ll need to work it loose using a coat hanger or hobby knife.

Step 2.

Insert your new weather-stripping, starting from the corners. You won’t need to apply any adhesive, here; it should slide into the groove with a reassuring ‘click’.

How do you replace a handle on a casement window?

When your handle is spinning, but the window isn’t opening, a broken shaft is normally to blame. In most cases, this problem can be fixed with a replacement handle. You can buy replacement cranks which can be adjusted to fit different spindles, or you can contact the manufacturer and ask for a like-for-like replacement. If it’s the shaft itself that’s worn down, you can often correct the problem temporarily by filing the edge of the shaft so that the screw can lock properly. Don’t expect this fix to hold up for long if you’re opening and closing the window repeatedly, however.

Anything else?

Casement windows are incredibly robust and given the right care and attention, they’ll last for years. To stand the best possible chance of avoiding problems, we’d suggest taking a pro-active approach. Check your windows periodically for damage and if you notice a problem, don’t be tempted to delay in fixing it. The chances are that it’ll only get trickier (and more expensive) to solve!

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Victorian windows

A Guide to Victorian Windows

The Victorian era was one of enormous transformation for British industry and architecture. It was also during the Victorian era that window tax (a property tax based on the number of windows a house had) was abolished.

This result was homes being built with more windows. The industrial revolution also brought plate-glass manufacturing techniques which made large, heavy windows more affordable. Victorian windows were predominantly of the ‘sash’ variety. Victorian sash windows did not open out on hinges in the same way as casement windows, but instead incorporated two or more panels which moved behind one another on tracks.

If you’re the owner of a Victorian property, you’ll probably want windows that match the exterior of the building.

How Do You Clean Victorian Windows?

Ideally, windows should be cleaned twice a year – once in autumn, and once as part of your spring clean. Try to clean your windows when it’s cloudy, so the soapy water won’t dry out quickly and leave unsightly streaks on the glass.

What cleaner should I use?

Vinegar will leave your windows super shiny – and it’s safe and natural, too.  It’ll break down any caked-on grime in seconds, leaving a gleaming surface that’ll give the window a new lease of life.

That said, vinegar isn’t all that effective at killing germs, so we’d recommend at least occasionally using a specially-formulated window-cleaner, or old-fashioned soap and water. Scrunched-up newspaper or microfibre cloth should be used to work the cleaner into the glass.

Repairing Scratches on Victorian Windows

If you’ve been unlucky, some of the glass panels that make up your window might have received knocks and scrapes over the years. These can usually be addressed with a little cerium oxide (or jeweller’s rogue, as it’s better known). You’ll need to do a lot of rubbing to get this to work – either by hand, or with the help of a polishing pad attached to your household drill. You can also get special scratch-repair kits. They’re designed for car windows, but will work just as well on Victorian sash windows.

How Do You Insulate Victorian Windows?

Most homeowners choose double-glazing to increase the energy efficiency of their windows. By trapping a layer of inert gas between two glass panels, the transmission of heat from one side of the window to the other is greatly minimised.

Unfortunately, the difference in pressure between the interior and the exterior of a double-glazed window can produce a pronounced ‘bowing’ effect, which somewhat undermines the authenticity of a Victorian-era property. As such, it’s often frowned upon by conservation officers.

So what alternatives are available to owners of Victorian homes looking to reduce their energy expenditure?

Secondary glazing

Secondary glazing works in much the same way as double glazing, except that rather than having everything contained in a single pressurised unit, another window is placed behind the first one.

This will improve heat retention without compromising its appearance from the exterior of the home.

Unfortunately secondary glazing is vulnerable to sagging over time. An alternative is a sheet of plastic which can be unrolled and attached to the sides of the window in winter, when heat-preservation is more of a concern.


Victorian sash windows aren’t generally as effective at keeping draughts at bay as casement windows.

There are various ways to reduce draughts in Victorian-era windows, ranging from quick masking-tape solutions to major overhauls which require disassembling the entire window. Replacing old and worn brushes with new ones can have a considerable effect on the window’s heat-retention. This is worth considering if your windows are particularly old.

We should also remember that Victorian properties were built to ventilate, and that blocking draughts can cause moisture to build up inside the property, which can in turn, cause damp and mould.

How to Dress Victorian Windows

If you’re fortunate enough to live in a well-preserved Victorian property, then it’s important to keep all of your décor consistent – and this extends right up to the window dressing. In the Victorian era, most windows were equipped with wooden blinds and shutters, which provided protection against sunlight on warm days, and security when the homeowner was away.

bay window

Many Victorian homes also have high ceilings, which will allow you to stack roman blinds over the top of your window, and operate them with a cord.

Finally, you might want to hang heavy curtains in front of your windows. This will prevent the cold air near to the glass from mingling with the warm air in the room. If you’re going down this route, then you might want to install two sets of curtains: a lightweight ‘voile’ set that’ll ensure privacy while permitting sunlight, and a heavier blackout set of curtains to go over the top.

If you’re going to achieve a consistent and authentic look for your Victorian-era home, then taking your windows seriously is a must – but that needn’t mean compromising too much on modern conveniences like energy efficiency. Through regular maintenance, cleaning, and the right dressing, you can ensure that your Victorian-style sash windows last the distance – and that they look fantastic, too.

Need new windows? Browse our sliding sash or casement windows or find out about our handmade bespoke windows.

Wintery street

How to Winter-Proof Your Windows

If, like most of us, you want to reduce your heating bills, you’ll need to pay close attention to your windows – largely because they lose heat much faster than the surrounding walls. This, as you might imagine, is especially important when temperatures drop, so it’s worth thinking about before winter arrives.

What are the Most Winter-Proof Window Designs?

Let’s look at a few popular varieties of window, and how effective they are at retaining heat.

Casement Windows

A casement window operates via a hinge, and usually opens outwards. This makes it compatible with draught-reducing silicon seals, which run around the edges of the window and are compressed when the window is closed. These seals will degrade over time, gradually losing their elasticity, and so must be replaced every so often.

Sash Windows

By contrast, a sash window moves up and down (or from side to side) within the frame. In place of soft seals (which would create friction and prevent the window from moving), sash windows feature draught-excluding brushes.

Like the seals in casement windows, these brushes will wear away over time, and so should ideally be replaced every few years.

Older Windows

If you’re the owner of an older property in a conservation area, the changes you can make to your home will be limited. This is because your planning officer will want any replacement windows to conform with your existing windows.

houses in a UK village

In fact, it can sometimes be tricky to get double-glazing installed in older properties. Firstly, the difference in pressure between the interior and exterior of a double-glazed window can produce a noticeable bowing effect on the glass. Then there’s the fact that double-glazing for period properties tends to cost considerably more than typical double-glazed windows.

That’s not to say that owners of older properties are out of luck – there are plenty of new windows which work well in older properties.

Bay Windows

Bay windows, technically speaking, aren’t windows.

They’re groups of several windows, arranged together. As such, bay windows can either be casement or sash. Given that bay window protrude slightly from the building, they’re a little more vulnerable to cold spells than most other types of window.

This means you’ll want to dress the windows properly and ensure they’re thoroughly maintained.

Arched Head Windows

Arched head windows feature an arch at the top for added visual interest. The top of the arch is usually sealed into place, with the bottom of the window functioning like a traditional sash window.

What is Best for Winter: Double or Triple Glazing?

Argon-filled double glazing is the gold standard for modern windows, but there are ways to make the technology even more efficient. You could choose windows with a denser gas, like krypton or xenon – but that’s often overkill, especially since they cost considerably more than argon-filled windows.

Another option is to increase the depth of the cavity, but this would result in an incredibly thick window, and exacerbate the bowing effect we’ve already discussed. What’s more, a cavity that’s too thick can create convection currents, via which heat can be transmitted from one panel to the other.

In Scandinavia and other particularly-cold parts of the world, a popular solution is triple-glazing. Triple-glazing is formed of, as you might have guessed, three panels of glass rather than two.

houses in Svalbard

Triple-glazed windows are trickier to manufacture than double-glazed windows, so they understandably cost more. They also reduce the amount of light entering the property’s interior, and how much heat is gained through sunlight exposure. As such, if your window is south-facing, you might end up reducing the energy efficiency of your property by installing triple-glazing.

We should bear in mind that winter is relatively short in the UK, so the added expense incurred by triple-glazing should be offset against the light-reducing effect it has for the rest of the year. For most of us, there are many energy-saving measures worth considering before triple-glazing is worth the expense.

Window Ratings Explained

If you’re comparing different windows, you’ll have probably encountered all sorts of arcane terminology. To confuse matters further, British and American manufacturers use different rating systems.


The u-factor (or u-rating) measures the rate at which heat flows from one side of a window to the other. The lower the number, the more efficient the window.

U-rating is usually determined using the centre of the glass, which means the effect of the frame is discounted. You should expect a good double-glazed window to achieve a u-rating of around 0.3. U-factor is related to R-value, which is more commonly used to calculate the efficiency of solid brickwork.

Solar Heat Gains Coefficient (SHGC)

Whenever sunlight hits your window, some of it will pass through, leaving the remainder to bounce away. In doing so, this portion will help heat your property. The higher a window’s SHGC, the more heat it gains through solar energy. In winter, this extra heat will make a difference to both your comfort, and to your energy expenditure.

Visual Transmittance (VT)

This works just like the SHGC, except instead of measuring the proportion of heat energy entering the building, we’re measuring the amount of visible light. The two don’t always correlate, as manufacturers add special coatings that filter out certain wavelengths.

Air Leakage (AL)

Air leakage measures the volume of air that can circulate through a window in a given timeframe. The lower the AL rating, the draughtier the window. In many cases, a little circulation is required to allow the building to ‘breathe’ and thereby prevent damp.

British Fenestration Rating Council (BFRC)

The BFRC are the central body responsible for upholding window standards in the UK. They issue licences to approved manufacturers, and stipulate which retailers are authorised to sell approved windows. To make things a little less confusing for the customer, each window approved by the BFRC comes is rated between E and A++. This rating combines all the measurements we’ve described into a simple grade, so it’s easy to make rough comparisons between different windows.

How to Insulate Your Windows for the Winter

Whatever windows you’ve chosen, there are several steps you might take to increase their heat-retaining abilities for the season.

Heavy dressing

Heavy curtains can reduce heat lost through the windows by preventing the cold air around the glass from mixing with the warm air in the room. To get the best from this, you’ll need to actually draw your curtains at night-time.

Secondary Glazing

Secondary glazing works a little like double-glazing, except instead of two glass panels built into the same unit, a second panel is fitted to the inside of the existing window. Since there’s no pressure difference, there’s no bowing effect. What’s more, you can remove the secondary glazing when the weather gets warmer.

You can also get flexible and rigid plastic secondary glazing, called winter window clings, which can be fitted to the window frame for winter.


As windows age, the seals which run around the edges wear out – i.e. the stuff that runs around the edge of the frame, and the brushes and rubber strips that sit on the frame’s inside. Make a habit of inspecting these every year, and replace them when necessary.

Draught Excluders

These are long, tubular cushions, often crammed underneath leaky doors. If your windows are draughty, they can serve the same purpose.

Low-e glass

Low-emissivity glass is glazing that’s coated with a very thin layer of reflective metal, that helps prevent heat escaping. Most modern windows are low-emissivity.

Need new windows? Browse our sliding sash or casement windows or find out about our handmade bespoke windows.

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