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Grants, Costs, and Price Guide for Double Glazing in the UK

Why Should You Invest in Double Glazing?

Double glazing is the technique of installing two panes of glass with a thin space of air between them. The gap is typically 12 to 16 mm wide and is sometimes filled with argon gas or just regular dry air.

It could be time for you to invest in double glazing if your energy bill or the noise outside is making you tense. A small air gap separates the two glass sheets used in double glazing, which effectively traps heat indoors. Double glazed windows and doors can significantly increase the value of your home.

Today, double glazing is found in six out of ten homes in the UK. Due to its ability to lessen heat loss and noise pollution, double glazing is a preferred option for households in the UK. Contrary to single glazing, double glazing can help you drastically lower your carbon footprint and save a lot of money on energy costs.

Fill out the quick form  to get up to 4 estimates if you’re interested in learning more about the installation and cost of double glazing. The services offered by GreenSavings Network are free and come with no additional responsibilities.

Window Double Glazing

Prices for double glazing

Double-glazing on doors

The Function of Double Glazing

Double glazing is a contemporary kind of building insulation that largely stops heat leakage. Double-glazed windows and doors have two panes of glass instead of just one. The tiny space between the two layers of glass, which is often filled with argon, xenon, or krypton, is what makes double glazing such an effective insulator.

The gas in double-glazed windows and doors lessens the convectional flow of heat. In essence, it slows down how quickly heat energy transfers from one side to the other.

Heat loss and noise are considerably decreased by the barrier that is created by the air that is trapped between the two layers of glass. Convection, a phenomenon that slows the flow of heat, is how double glazing works.

In other words, the air between the panes cannot adequately circulate because to the too-small gap, which significantly slows down the transmission of heat. Double glazing’s insulating qualities are a result of this procedure.

Even though heat transfer cannot be completely halted, it can greatly reduce heat loss and cost you significantly less money.

As a result, a structure with double-glazed windows and doors may experience a total temperature difference of up to 20 degrees between the inside and outside of the structure.

What Make Up the Parts?

The following six elements are crucial to double-glazed units:

the glass, the hollow, the first and second seals, and the spacer bar.

Two sheets of annealed, tempered, or laminated glass are typically used in double glazing. Additionally, you can choose from coloured, tinted, or reflective glass.

The spacer bar that separates these sheets creates a cavity that traps air, providing double glazing its insulating capabilities. The desiccant in the spacer frame typically absorbs all moisture to stop condensation from forming between the panes.

Two seals, the primary seal and the secondary seal, are linked to the glass to effectively trap heat while preventing further moisture from entering the double glazing. The secondary seal is attached to the back of the spacer frame, and the primary seal is attached to the exterior, around the glass panes.

Window Double Glazing

When purchasing double glazed windows, there are many different factors to take into account. Two of the key elements are costs and kind.

Double-glazed window cost

The price of double-glazed windows for your home is based on a variety of variables. Of course, the cost will vary depending on the size of the window and how much you want to buy. The price will increase as the window size or the number of windows required increases. In general, most businesses provide discounts if you purchase many double-glazed windows.

Another key factor is the composition of the frame. Due to its low cost, UPVC is the most preferred alternative for double glazing. Aside from their desired looks, other framing materials like wood and aluminium are more expensive but offer no advantages over uPVC.

Given both sash and casement uPVC windows are frequently chosen in the UK, we have listed their approximate pricing in the table below.

Prices for White Casement Windows
Number of
Number of White uPVC casement windows
(600mm x 900mm)
Average cost
2 4 windows from £1,000
3 9 windows from £2,250
4 15 windows from £3,750
Prices for White Casement Windows
Number of
Number of White uPVC sash windows
(600mm x 900mm)
Average cost
2 4 windows from £2,000
3 9 windows from £4500
4 15 windows from £7,500

Remember that the costs associated with double glazing cannot be summed up into a single set amount. Instead, the majority of glazing businesses will schedule a free meeting for a member of their staff to visit your home and assess the cost of double glazing based on your requirements. If you wish to compare double glazing prices, go here.

Different Double Glazed Window Styles

The type of window in your home is a consideration that will also impact the cost of double glazing. Customers can choose from a broad variety of different designs and styles thanks to double glazing providers. The most well-liked ones are these:

Bay Windows

Round Windows

Casement Windows

Sash Windows

Tilt & Turn Windows

Awning Windows

Fixed Windows

Dual Turn Windows

Secondary Windows

Palladian Windows

Double-glazing on doors

Similar to double-glazed windows, the price of double-glazed doors depends on a variety of criteria. Below, you’ll find some details regarding the double glazed doors’ prices and types.

Double-glazed door prices

Prices for doors are often most affected by the framing material and design. The least priced alternative is UPVC doors, whereas aluminium and wood are more expensive.

Sliding patio doors are typically less expensive than folding patio doors. In comparison to the other two, bi-fold doors are the most complicated and costly.

The average cost for the supply and installation of these kinds of double glass doors is shown in the table below.

Cost of White uPVC Doors
Type of Door Number doors Average cost
Sliding Patio 2 doors from £1,200
French 2 doors from £1,000
Bi-fold 2 doors from £1,500

The information above is relevant to doors with standard sizes. It’s crucial to remember that double glazing firms custom fit the doors to your home. As a result, prices and sizes differ from home to home

Different Double Glazed Door Types

The same as with double-glazed windows, double glazing businesses provide you with a selection of several door types and shapes. A handful of such are as follows:

Entry Doors

Dual Fold Doors

Outdoor Doors

Frech Style Doors

The UK’s Top Double Glazing Companies

In the UK, there are numerous businesses and organisations with a focus on double glazing. Before selecting the installer and manufacturer of your windows and doors, it’s crucial to complete your research. To help you decide a little bit simpler, we picked up a few of the greatest ones.

Manufacturers of double glazing

Rehau, Crittal, and Eurocell are a few of the top double glazing producers in the UK.

If you’re looking for high-quality uPVC products that come in a variety of forms and colours, Eurocell and Rehau will be able to meet your needs. Both businesses, which have garnered numerous accolades, concentrate on creating recyclable and energy-efficient doors and windows.

Crittal is the company to go with if steel windows are something you’re interested in. They put their products through a rigorous procedure, and because of their adaptability, they are suitable for both new and ancient residences.

Dual Glazing Installers

The biggest and most seasoned double glazing businesses in the UK include Safestyle UK, Everest, and Anglian Ltd.

They have all been in operation for some time, and their clients appreciate their knowledge and high calibre double glazing. While Safestyle gives you an online quote, Anglian and Everest only do it after one of their staff members has visited your home.

When selecting one of these double glazing installers, you will have the option to price-compare with other businesses and select a financing option.

Dual Glazing Industry Organizations

Find a reputable and expert double glazing organisation to guarantee that your double glazing is installed appropriately.

The Glass and Glazing Federation-implemented FENSA and Certass are two government-approved programmes that collaborate with a number of double glazing contractors. As you are required to receive guarantees and warranties for the installation of your double glazing, their services defend your rights.

The Double Glazing & Conservatory Ombudsman Scheme, often known as DGCOS, is another programme that provides you with additional security.

Five Benefits of Double Glazing

Four drawbacks to double glazing

Double-glazed glass and various frame types

To establish the ideal fit for your home, several double glazing providers offer a variety of frame materials and glasses. The spacer bar and the type of gas used to fill the space between the panes can both be customised in addition to the frame material and glass.

Different Frame Types


The most common window and door frame option for double glazing is unplasticized polyvinyl chloride, or short uPVC frames. They typically cost less but offer comparable insulation to other frame materials. uPVC frames come in a wide range of colours. Do keep in mind that it is advised to choose uPVC frames with a warranty of at least 10 years because the colour may fade and the frame may expand over time if exposed to harsh sunlight.


Compared to other framing materials, wooden frames have a more traditional appearance. With proper maintenance, they can make double glazing 1800 times more insulating than aluminium frames. But compared to uPVC frames, timber frames are unquestionably more expensive and require more maintenance.


Aluminum frames provide an extremely modern and contemporary appearance. Due to the durability and low maintenance needs of aluminium, they might last you a very long time. However, it is less insulating than uPVC and timber, making it the least preferred option among the three for double glazing.

Various Styles of Glasses

You can change the type of glass used in your double glazing in addition to the frames.


One of the most common glass options is low-emissivity, or low-E, glass because it increases the energy efficiency of double glazing. While letting sunlight in, low-e filters out dangerous UV and infrared rays. This keeps the heat inside during the winter.

Broken Glass

This kind of glass is safety glass. Since it is more robust than typical annealed glass, the danger of injury and accidents when it breaks is lower.

Leaded Glass

like toughened glass A common option for safety and security glass is laminated glass. It is extremely hard to break because it has two layers.

Dark Glass

a film that is added to double glazing to cut down on ultraviolet light transmission through doors and windows. It provides you with more privacy and shields your furniture from the sun. It also helps to keep your home cooler in the summer.

Mirrored Glass

a metallic coating that gives windows and doors a more contemporary appearance. By reflecting radiation, it efficiently cools your house in the summer and warms it in the winter.

Decorative Glass

Almost any colour is available in a variety of glass kinds. Different metals are added to molten glass to produce coloured glass, which is then utilised in the double glazing process.

Is Repairing Double Glazing Simple?

Many web forums offer Do-It-Yourself advice on how to fix double-glazed units, but we don’t advise doing it yourself in this situation.

There are numerous potential ways that your double glazing could have become damaged. Condensation is a defect that arises frequently through wear and tear over time. You should notify your installer right away if you discover this issue with one of your double-glazed windows or double-glazed doors. You ought to be able to receive complete coverage for the repair if your warranty is still in effect. If not, you might need to spend money on new double-glazed units

Are There Any Double Glazing Alternatives?

supplementary glazing A secondary internal window or door is attached to an already existing unit using secondary glazing. Compared to double glazing, it is less expensive primarily because it is a DIY project.

Secondary glazing could save your energy costs by up to 10%, but it does not retain heat as effectively as double glazing. The overwhelming victor, however, in terms of noise reduction, is secondary glazing.

In general, secondary glazing can be an excellent substitute for double glazing if you want to reduce costs and improve acoustic insulation.

The term “triple glazing” refers to the use of three panes joined together similarly to how double glazed units are. Triple glazing is more energy-efficient than double glazing because it traps more heat inside. Additionally, it is more resilient and noise-canceling.

However, triple glazing is more expensive, and because the glass is so heavy, it needs stronger framing materials, which raises the price. In the world’s colder regions, triple glazing would be most effective. So triple glazing might be the answer for you depending on where you live in the UK.

Quadruple glazing: There are a total of four layers of glass in quadruple glazing. In contrast to double glazing, quadruple glazing is still a relatively new product in the UK, and few window and door fitters offer it. Compared to triple and double glazing, it is more energy-efficient and acoustically insulating.

The additional layer does have a price, though. According to estimates, quadruple glazing costs about £1000 more per unit than triple glazing.

Locate the UK’s Top Double Glazing Businesses

When determining who should install your double glazing, we at GreenMatch are aware that it might be difficult to make a choice. It takes time and effort to find the ideal supplier that can meet your demands and desires. We’re prepared to assist.

Remember to complete out our form  if you want to add double glazing to your home to improve style, security, and sustainability. Free and without any further commitments, you can receive up to 4 quotations from reliable vendors.