The average price for a white UPVC double glazed casement window measuring 1 metre by 1 metre is around £300. For a bigger window measuring 120 centimetres by 120 centimetres, the cost will be between £350 and £400.
Which factors influence the final price that you pay for your double glazing? There are a number of different factors including the size of the windows you choose to have installed, the number of windows, the style of the windows, the material used for the frames, the company you choose to do the work, and whereabouts you live in the country.
More and more of us live in apartments than ever before and the average cost to replace the windows in an apartment with the newest double glazing is between £1,550 and £2,750.
For smaller detached houses or large semi-detached properties with 12 windows, homeowners should budget between £4,900 and £7,600 for brand new double glazing.
The prices that we’re quoting have all been sourced from smaller, local suppliers. Homeowners are increasingly finding that regional independent installers can deliver the same high specifications in the windows themselves, the installation service, and after-care that they can expect from larger, nationwide suppliers.
The difference is that smaller installers generally charge a lot less because the overheads they have are a lot lower than their national rivals – there is no big showroom network, television advertising costs, or salesmen’s commissions to pay for.
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Comparing Double Glazing Companies
Get up to four quotes from trusted and checked suppliers local to you by filling out the form below:
Because double glazing requires such a significant financial investment, homeowners rightly do as much as they can to get the highest quality installation possible at the lowest price.
For a 12-window installation, the quotes we received from partner suppliers, as you saw above, started at around £4,900. However, by getting installers to compete with each other, you might be able to get exactly the same work done using the highest quality products and installation standards for as little as £4,000. Within this £4,000, your budget would include varying windows sizes, window features like frosting for the bathroom, and you may even persuade an installer to include a new and fully fitted uPVC front door within the cost.
Use the form above to compare double glazing companies and their price lists for 2021 to get the clearest picture and the best deal.
We compare suppliers and offers and provide you with three bespoke quotes local to you. This is the fastest and safest way of obtaining the best deals on Double Glazing in your area.
What are the benefits of Double Glazing?
Double glazing is one of the most expensive and extensive home improvement projects you can undertake so, before you make any decision about having it installed, you need to be certain that buying double glazing will save you money in the longer term.
Double glazed windows retain 10% more of the heat in your home meaning that the cost of running your central heating will be considerably less. Double glazing lasts for 25 years and, over that length of time, what you save on your utility bills may actually add up to more than you actually paid for your new windows. A particularly important benefit for families is the increased security that double glazing provides – there is no price to put on the safety of yourself, your family, and your possessions. Most insurers now offer a discount on their premiums if modern double glazing has been installed at a property too.
Types of double glazing
Double glazing is available in a variety of different styles. In this article, we’ll explain the features and benefits of each type of windows together with examples of prices (before VAT and installation) provided by independent local installers.
UPVC white Casement
Casement windows are Britain’s most popular because of the competitive price they’re available for and their innate modernity and stylishness. Although casement windows are available with no openings, we wouldn’t recommend it because you won’t be able to let any fresh air in on warm days.
Casement windows with hinges are great for allowing lots of that fresh air to circulate around your rooms and your home on a sunny day. You can also choose whether you want the windows to open outwards or inwards – outwards is a popular choice for homeowners who have furniture or seating placed under their windows.
One of their in-built security features is to limit the degree to which the window itself will open – great for keeping burglars out and an additional layer of safety against curious toddlers from getting out. Ask your installer to show you samples of the different types of casement window including pivoted/centre-hinged, hopper/bottom-rung, awning/top-hung, sliding folding casement, top light casement, and side hung casement. There is certain to be the right type of window to suit you and your family’s needs from this enhanced range of options.
| Window type | Height | Width | Prices range |
| UPVC white Casement (no opening) | 500mm | 500mm | £150-£175 |
| UPVC white Casement (no opening) | 1000mm | 500mm | £175-£200 |
| UPVC white Casement (no opening) | 1000mm | 1000mm | £210-£250 |
| UPVC white Casement (no opening) | 1200mm | 1200mm | £235-£275 |
| UPVC white Casement (one opening) | 500mm | 500mm | £260-£300 |
| UPVC white Casement (one opening) | 1000mm | 500mm | £275-£320 |
| UPVC white Casement (one opening) | 1000mm | 1000mm | £305-£350 |
| UPVC white Casement (one opening) | 1200mm | 1200mm | £355-£400 |
Click To Get QuotesFrench uPVC white Casement
A popular but expensive variation of uPVC casement windows is the uPVC French-style casement window. Unlike with standard casement windows, there is no supporting bar across the middle of the frame.
Both sides can swing open (either inwards or outwards) for maximum ventilation and to give the clearest and most unobstructed view of the outside world. On the hottest of days, we think that nothing will cool a room faster or quicker than having French uPVC white casement windows on your property.
French casement windows cost around 60% more than standard casement windows with one opening.
| Window type | Height | Width | Price range |
| UPVC white French-style Casement | 500mm | 500mm | £455-£495 |
| UPVC white French-style Casement | 1000mm | 500mm | £480-£515 |
| UPVC white French-style Casement | 1000mm | 1000mm | £510-£545 |
| UPVC white French-style Casement | 1200mm | 1200mm | £535-£570 |
Tilt/turn windows
Tilt/turn windows are an increasingly popular choice because of their attractiveness, their effectiveness, and their versatility. They are a superb choice for homeowners wanting maximum ventilation on hot days and they’re also very low maintenance because of the high manufacturing standards employed during their production.
Tilt/turn windows use specially placed handles to the side and the top of the frame. If you use the top handle to open the frame, it tilts inwards or outwards from the bottom allowing a greater degree of control over the amount of air inflow into your rooms and your home. If you use the side handle, it opens outwards or inwards like a casement window – great for when lots of ventilation is needed on a hot day. Tilt/turn windows cost about 50% more than standard casement windows with one opening.
| Window type | Height | Width | Price range |
| uPVC white Tilt & Turn | 800mm | 800mm | £405-£445 |
| uPVC white Tilt & Turn | 1000mm | 800mm | £455-£458 |
| uPVC white Tilt & Turn | 1000mm | 1000mm | £480-£520 |
| uPVC white Tilt & Turn | 1200mm | 1200mm | £510-£540 |
Click To Get QuotesSash windows
If there was a classically British style of window, it would certainly be the casement window. This is the type of window style you’d most expect to see on a historic or period property like a Georgian townhouse.
A sash window has two layers of double glazing – one at the top and one at the bottom. The sash window uses the frame as a tramline so that you can slide one of the layers either horizontally or vertically – in most cases, you slide the bottom layer up the tramline to open the window. You can fully open the window by bringing the bottom layer fully up to the level of the top layer or you can just open it gradually to your own preference.
You can choose sash windows for your new double glazing at a premium of around 20% more than French casement windows or double the price of casement windows with one opening.
| Window type | Height | Width | Price range |
| uPVC white Sash | 500mm | 500mm | £535-£590 |
| uPVC white Sash | 1000mm | 500mm | £610-£695 |
| uPVC white Sash | 1000mm | 1000mm | £635-£700 |
| uPVC white Sash | 1200mm | 1200mm | £740-£815 |
Double hung sash windows
A variant on the double-glazed sash windows is double glazed double hung sash windows. They are very much in style at the moment because of their superior aesthetics but they do come at a steep premium in comparison to the prices that you’d pay for standard sash windows.
With double hung sash windows, both layers of the window can be moved up or down. Whereas with standard sash windows, you can only let the air in by lifting the bottom layer up towards the top layer, you can move the top layer down to the level of the bottom layer with double hung sash windows.
Double hung sash windows are generally considered to be better for security (people getting out) and safety (toddlers and children getting out) than standard sash windows.
Bay windows
Another classic British style reminiscent of some of the grand houses and sweeping terraces from the 19th century, bay windows offer homeowner extra living space and an elegant vista to the outside world.
Bay windows are actually a collection of normally three, four, or five windows side by side which pleasantly angle outwards and then back inwards. You may often hear three-section bay windows referred to by installers as box windows.
| Window type | Height | Width | Prices range |
| uPVC white Bay Window (3 sections) | 2400mm | 1200mm | £1,070-£1,125 |
| uPVC white Bay Window (3 sections) | 2400mm | 1500mm | £1,150-£1,200 |
| uPVC white Bay Window (3 sections) | 3000mm | 1200mm | £1,175-£1,225 |
| uPVC white Bay Window (3 sections) | 3000mm | 1500mm | £1,275-£1,325 |
| uPVC white Bay Window (4 sections) | 3000mm | 1200mm | £1,425-£1,470 |
| uPVC white Bay Window (4 sections) | 3000mm | 1500mm | £1,530-£1,565 |
| uPVC white Bay Window (4 sections) | 3600mm | 1200mm | £1,585-£1,620 |
| uPVC white Bay Window (4 sections) | 3600mm | 1500mm | £1,645-£1,675 |
| uPVC white Bay Window (5 sections) | 3600mm | 1200mm | £1,885-£1,935 |
| uPVC white Bay Window (5 sections) | 3600mm | 1500mm | £1,990-£2,110 |
| uPVC white Bay Window (5 sections) | 4000mm | 1200mm | £2,040-£2,110 |
| uPVC white Bay Window (5 sections) | 4000mm | 1500mm | £2,120-£2,205 |
Bow windows
Bow windows are a variation on standard bay windows. Often referred to by installers as compass windows, up to eight panels placed next to each other form a grand but subtle sweep out from and back into your property’s outer wall. The most dramatic bow windows actually cradle a property on one side of a home stretching around to another forming a stunning turret shape.
| Window type | Height | Width | Prices range |
| uPVC white Bow Window (3 sections) | 2400mm | 1200mm | £1,085-£1,130 |
| uPVC white Bow Window (3 sections) | 2400mm | 1500mm | £1,160-£1,210 |
| uPVC white Bow Window (3 sections) | 3000mm | 1200mm | £1,185-£1,240 |
| uPVC white Bow Window (3 sections) | 3000mm | 1500mm | £1,285-£1,335 |
| uPVC white Bow Window (4 sections) | 3000mm | 1200mm | £1,430-£1,485 |
| uPVC white Bow Window (4 sections) | 3000mm | 1500mm | £1,530-£1,590 |
| uPVC white Bow Window (4 sections) | 3600mm | 1200mm | £1,580-£1,620 |
| uPVC white Bow Window (4 sections) | 3600mm | 1500mm | £1,630-£1,670 |
| uPVC white Bow Window (5 sections) | 3600mm | 1200mm | £1,875-£1,970 |
| uPVC white Bow Window (5 sections) | 3600mm | 1500mm | £2,015-£2,125 |
| uPVC white Bow Window (5 sections) | 4000mm | 1200mm | £2,040-£2,160 |
| uPVC white Bow Window (5 sections) | 4000mm | 1500mm | £2,065-£2,195 |
Click To Get QuotesBut Which Type is Best?
There is no such thing as the best double-glazed window that money can buy. Every homeowner has their own needs and taste and don’t forget that every homeowner’s choice needs to be compatible with the budget they have set aside.
Tilt turn windows offer additional safety features for families with young children however all the windows we’ve described, with the possible exception of single sash windows, keep toddlers and other children safe with restricted opening. You will doubtless have your own list of boxes you want to tick with your double glazing and the best people to take advice from are the installers who help homeowners like you make the right choice for their living.
One important aspect to consider when choosing double glazing is energy efficiency. Just like the electrical appliances you have around your home, double glazing has its own rating system measuring how energy efficient they are. Legally, no window can be installed now in the UK which has a grading lower than C to be compliant with the Government’s building regulations. In order to save the most money on your electricity and gas bills possible, try to select windows at or as near to A+ grade as possible. The higher the energy efficiency, the less the amount of heat will escape from your home keeping you and your family warm all year around.
How does double glazing actually keep heat in? Double glazing works by placing two sheets of glass very close to each other with the space in between filled with argon glass. Argon glass is an inert and non-reactive gas which allows the heat in but doesn’t let it all bounce straight back out of your home. In addition to preventing heat from leaving your property, the argon gas also provides homeowners with great noise insulation properties, particularly useful if you live near a busy road.
Windows and frames
The thicker your double-glazed windows, the better the glass and the argon gas are at keeping heat in and keeping noise out. Depending on how large your window is, the standard thickness of double glazing within the framing is between 14mm and 28mm.
There are three main types of framing used in double glazing installations in the UK – uPVC, wood, and aluminium. The most popular choice of framing is uPVC because of the considerable savings it offers to homeowners in comparison to the two other choices. But there are other benefits too – for example, uPVC is very low maintenance and wipe-clean. Looking after it is much easier than worrying about what to do about wooden frames that may be beginning to rot or aluminium frames whose paint has been chipped away.
Although uPVC technology and the designs now on sale are far better from the uPVC many of us might remember from the 1980s and the 1990s, the material is still not to everyone’s taste though. Aluminium is very much in vogue at the moment – just check out home furnishing magazines to see how often they’re featured. Aluminium offers the slenderest frames to homeowners meaning that you see more of the outside world unobstructed compared to uPVC or wood. Wooden frames look magnificent, classical, and stylish, especially on period properties, but, as with aluminium, it costs a lot than uPVC to install and badly manufactured wooden frames can deteriorate surprisingly quickly.
Double Glazing vs Triple Glazing
Tripe glazing is particularly popular in the Nordic countries but it has yet to catch on here in Britain just yet. Triple glazing is particularly suitable for homes in very cold environments because of its enhanced ability to keep in the warmth in comparison to double glazing. The reason it does it better is that the spaces between the panes of glass are filled with krypton glass rather than argon gas and because the frames themselves have additional layers of insulation.
According to one recent study, a room with a triple glazed window is up to 18 degrees warmer than a room with single glazing and between 2 and 7 degrees warmer than a room with double glazing. The industry is also examining the potential of quadruple glazing although limited demand for it is impeding any significant investment in the technology just yet.
Triple glazed windows offer even greater energy efficiency than double glazed windows and they also have better noise insulation qualities too. Triple glazed windows do cost more than double glazed windows because of higher material and production costs and they are harder to fit to a property too meaning that labour charges for installation will also be higher. Triple glazed windows also let slightly less light into a property however, in most cases, a homeowner would struggle to see the difference.
Replacement Double Glazing
If you’re now ready to make an investment in double glazing for your home, you’ll need to know as much as you possibly can about double glazing to make sure that the installation you eventually decide on is the right one for you.
The major advantages of double glazing are that you will keep more heat in your home, that your home will be more secure, and that, when the time comes to sell your property, it’s far easier to find a buyer for a home with modern windows than one with old-fashioned single glazing.
Double glazing, in most cases, will last between 20-25 years and most manufacturers now offer a guarantee of at least 10 years to customers. The main problems that occur with double glazing installations are condensation between the panes, leaks, chips, cracks, and draughts.
What if I can’t have Double Glazing?
Double glazing is, in nearly all cases, considered a Permitted Development for building regulations purposes however for owners of listed properties and for owners of properties within conservation areas, additional rules apply which may mean that double glazing is not going to be an option for your home.
Are there any alternatives to double glazing? You should consider secondary glazing although the performance of Secondary Glazing does not match that of Double Glazing – however, it is superior to just having a single glass layer windows.
Double Glazing FAQ
Who can fit Double Glazing?
Certain home improvements require specialist and accredited individuals to perform the installations – like a boiler needs to be installed by someone who is on the Gas Safe Register. There are no such rules regarding the installation of double glazing and homeowners are perfectly free to buy their double glazing direct from a manufacturer and to install it themselves.
DIY double glazing may be a way to save money on the cost of the overall job but there are potential complications if you decide that this is the course of action you want to take. Many window manufacturers will only stand by their guarantee if their windows are installed by a company which is accredited to or members of certain organisations like:
- Glass & Glazing Federation (GGF),
- The Fenestration Self-Assessment Scheme (FENSA),
- Certification and Self-Assessment (CERTASS), or
- FairTrades / TrustMark accreditation
There is also a significant safety risk in installing your own double glazing because it is more than a one-person job. Were the worst to happen and you injured yourself during the installation, your property will be vulnerable until the work is complete and you may lose money because of the time you have to take off from work.
As with all major home improvement projects, it is always better to either let a professional do it for you or to work in partnership with a professional. It’s important to remember that the savings that you make with a self-install will be limited – you will probably pay far more for the materials than your installer would because the company you choose to do the work will benefit from trade-only discounts.
Click To Get QuotesWho is the cheapest Double Glazing Company?
For homeowners looking for the best deal, this is the often most important question. There are many national companies advertising on TV and with local branches on high streets and on industrial parks all of which offer the highest-quality products, have some of the best fitters in the business, and teams of people looking after customer support.
All of that, plus salesmen commission of up to 20% of the price of your installation, comes as a cost to you though. And all of those extras are included in the final price you pay. Be particularly cautious if you are offered a special, one-day only offer where the salesman phones the branch manager for “authorisation”. This is a familiar tactic, designed to strong-arm a cautious customer into committing to a decision that they may not be ready to make.
It is always advisable to shop local and find a reputable company, preferably one that has been established for over ten years. Double Glazing is a substantial investment and taking a budget option now may prove to be an error when the time comes for you to sell your home.
We canvassed some of the trusted local suppliers we’ve partnered with throughout the UK and below you can see the average quotes we got on particular jobs:
| Property to be fitted | Number of windows (average) | Range of costs (uPVC white casement) |
| Flat | 4-5 | £1,550-£2,750 |
| Small house | 8-9 | £3,300-£4,950 |
| Medium-sized house | 10-12 | £4,900-£7,600 |
| Large house | 15-18 | £7,200-£11,600 |
The cost of your installation will depend on a number of factors. The figures above are initial quotes but we know that, when smaller independent suppliers are in competition with each other, prices come down but not at the cost of quality of product, installation skill, or customer service.
By comparing quote from different traders and by letting them know that they’re not the only company you’re talking to, you may secure up to a 30% discount on the prices shown above.
Which Double Glazing should I buy?
Which double glazing you should buy depends on three major factors – your budget, your personal preferences, and the building you live in. Older homes are more difficult to buy double glazing for because owners want to keep the character and the style of their property and any double glazing that they purchase for their home must be in keeping with that character and style.
With more modern buildings, there is much greater scope for flexibility and experimentation. A recent trend among homeowners has been the increasing popularity of tilt/turn windows because of the increased security and airflow they offer.
The world of double glazing offers far more options than many homeowners realise – the market has moved on a lot over the last fifteen years driven by customer demand for a wider range of options better suited to provide for today’s lifestyles. The best thing to do is to speak with an installer in your own home who can better understand what you want from your double glazing and the type of building you live in.
Why is Double Glazing better?
There are many different reasons why you should choose modern double glazing, even if you have double glazing that is 15 years old or more and particularly if you have single or secondary glazing. Single glazed windows struggle to retain heat and, as a result, they push up homeowners’ gas and electricity bills in the cold of winter.
To the naked eye, double glazing lets in just as much light as single glazing however three in five homeowners believe that their home is warmer since they switched to double glazing. The extra insulator properties of double glazing also keep destructive elements at bay with the risk of damp greatly reduced in homes which have upgraded their windows recently.
Do you live near a busy road, a pub, or somewhere else where people congregate regularly making a lot of noise? The technology in double glazing that keeps heat in your home also greatly reduces the noise coming into your home from the outside. The better the quality of your windows, the warmer and quieter your home will be.
Many families also appreciate the additional security brought to them with the installation of double glazing. That’s not only additional security against potential intruders but the substantially decreased likelihood that something hitting your windows during high winds or a game of football in the back garden will mean a call out to the glazing replacement firm because your window has been put out.
Why is Double Glazing so expensive?
Double glazing costs as much as it does because of the quality of the materials manufactured for your installation and because of the costs of installation. Fitting double glazing is difficult and it requires skilled and experienced tradesmen to get it right.
Every home is different too. Each double-glazed window fitted on to your property is bespoke to your property. And each property at which double glazing is installed has its own flaws and characteristics which often require extra attention from an installer to put right before a particular window is fitted.
Click To Get QuotesWhen should I replace my Double Glazing?
The tell-tale signs that your double glazing needs replacing are increased and stronger draughts that you can feel around your property, condensation in and around your windows, and chips & cracks to both the windows and the frame. Experts recommend that you replace your double glazing when one or more of the following appears in your home:
- Are your windows looking tired? You could always try to maintain them yourself but, if there is mould and damp around the frames or one or more of the windowpanes is cracked, it might be more economical over the long run to replace your windows now.
- Rotting wooden window frames? Wooden frames can last a very long time but, even after its thorough treatment in the factory, it is still a natural substance prone to slow degradation and eventual rot. If rot has started to appear, you will be losing a lot of heat from your home and, over time, the frame itself may become dangerous and unstable.
- Difficult to operate your windows? Are you finding it much harder than before to open or close your windows? The hinges will be reaching the end of their life and, over time, they are likely to become a security risk because entry will be much easier to force.
- Is your home cold? And, even putting aside the seemingly annual rise in utility bills, does what you’re paying for gas and electricity seem like it’s getting out of control? This is a likely sign that your window seals are starting to fail – if this is so, you may have also noticed condensation between the windowpanes.
- Effect on your furniture – as double-glazing ages, it lets more harmful uV rays into your home and, over time, this will fade the colours on your furniture, carpets, and sofa.
What are my rights when buying Double Glazing?
There are a number of rights that homeowners enjoy to protect them when purchasing double glazing. Your installer must tell you in advance the anticipated cost of the work you intend to have done prior to your signing any contract.
If you sign the contract in your home, you are entitled to a cooling off period of 14 days – this is known as an “off-premises contract”. If you sign the contract outside your home, for example in the installer’s showroom, then there is no legal requirement for the company to provide a cooling off period although, in the interest of best practice, many do. However, please always check before committing to anything.
All purchases over £100 are covered by the Consumer Credit Act of 1974. You may wish to part pay for your installation on a credit card because, if something goes wrong later on, your credit card company will be equally liable for any breach of contract, even if the amount you paid on a credit card was minimal in comparison to the overall cost.
How do Double Glazing windows work?
Today, most homes are built with an outer wall and an inner wall (or “leaf”). The gap between these walls is the cavity and one way to keep more heat in your home is to purchase cavity wall insulation. The material used in cavity wall insulation makes it much harder for the heat in your home to escape to the outside.
Double glazing uses the same principle with argon gas between the two panes contained within your frames. When heat reaches the window it will seek a conductor and the condensed air between the two windowpanes is a vacuum. As a result, the heat will stay in your home for longer.
This extra barrier will also protect your home from exterior noise. Instead of just a solitary pane of glass, any sound will need to infiltrate the outer pane, negotiate its way through the vacuum of condensed air, and then pierce the interior window.
How does Double Glazing save energy?
Yes – because less heat escapes through your window, you don’t need to use your radiators as much. Because you use your radiators and your storage heaters much less, you don’t need to use as much energy and, as a result, your heating bills go down. See “How do Double Glazing windows work?” and “How does Double Glazing reduce heat loss?” on this page for more information on how this works.
Are grants available for Double Glazing?
Unfortunately, the government’s Affordable Energy initiative does not cover the cost of Double Glazing windows even though it does provide grants for cavity wall and loft insulation. However, on rare occasions, grants are issued under this scheme, particularly for aged properties in a state of disrepair. It may be worthwhile making enquiries to find out if the scheme applies to you.
What is Argon Gas, and why is it so important for Double Glazing?
As we mentioned earlier, in the way that insulation inside a cavity wall stops heating from escaping, so does the Argon Gas contained inside the windowpane.
Argon is a non-toxic, tasteless, colourless, and odourless asphyxiant gas which is 38% denser than the air in the atmosphere. Argon differs from cavity wall insulation in that, while it is superbly effective at stopping heat from escaping, it lets in a lot of the ambient heat from the outside into your home further reducing your need to use your central heating to warm your home.
Alternatives to Argon include Krypton and Xenon. These gases are even more effective at retaining heat, but come at a higher cost, and are thus usually reserved for Triple Glazing projects. Krypton and Xenon also require increased width between windowpanes to be effective.
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