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Jump to: Benefits of double glazing windows | Double glazing costs | Best double glazing windows companies | Double glazing styles | How to select the right installer for you | What are my rights when buying double glazing windows? | Conclusion | Methodology
Double glazing windows were introduced in the 1970s, and since then have grown in popularity. The 2002 building regulations made it mandatory for new and replacement windows to be double glazed with a minimum efficiency rating of C. With the added benefits of thermal insulation, lower energy bills, noise reduction, and increased security, it’s no wonder that double-glazed windows are now the norm for UK homeowners.
With such high demand, double glazing suppliers are plentiful, many offering different design features to satisfy style-conscious homeowners. From bevelled glass to antique-style handles, the choices can be overwhelming. So what criteria should you bear in mind when selecting a supplier for your new windows? And how do you know which supplier to trust?
To help you, we’ve researched the best double glazing window companies in the UK in 2025. We look at the different styles offered, the energy ratings, prices, customer reviews, guarantees, and services—everything you need to select the best double glazing company for your project.
What are double glazing windows?
Double glazing windows consist of two panes of glass, separated by a layer of air or inert gas—usually argon—and set in a sealed, framed unit. Thermal transfer slows thanks to the air or gas-filled layer, meaning that the warm air inside your home escapes at a much-reduced rate. This allows rooms to remain warmer for longer, making heating systems more energy efficient and saving money on household bills.
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How will installing double glazing windows benefit you?
UK homeowners rave about the benefits of this proven technology. Here are some of the many advantages of double glazing windows.
Increased security
Double-glazed windows are much safer than single-pane ones. They are harder to break and the seals around them further protect against burglary. Most companies also provide add-ons such as security glass and locking features to further deter break-ins.
Reduced energy bills and higher thermal insulation
Double-glazed windows are designed to provide better thermal insulation than single-glazed windows. This translates to lower use of your air conditioning and heating systems, saving you money on your energy bills in the long run.
Reduced condensation
Condensation forms on your windows when they are cooler than the temperature inside your house. It can lead to the growth of mould and mildew, which can rot your wooden frames. Double-glazed windows help prevent this because the inner pane is closer in temperature to that inside the house.
Noise reduction
The additional pane of glass and the internal gas layer of a double-glazed window can reduce noise by 19%–57% when compared to single panes.
Higher property value
Double glazing makes a home more energy efficient and comfortable—and more attractive to potential buyers. Research shows that sellers can earn up to 10% more for their homes with double glazing.
How much do double glazing windows cost?
The final cost of your double-glazed windows depends on a number of factors, including which company you choose to do the installation, how many windows you need, the materials you decide on, and whether you choose speciality glass. As a general rule, you can expect uPVC casement windows to be among the least expensive options, while aluminium, timber, and composite frames will be on the higher end of the price scale.
Below is an outline of the average price you can expect to pay based on the number of windows being installed.
| Number of windows | Cost (excluding installation) |
|---|---|
|
4–5 |
£1,000–£1,250 |
|
6–10 |
£1,500–£2,500 |
|
10+ |
£2,500+ |
Best double glazing window companies in the UK
- Anglian: Highest rated
- Everest: Best guarantees
- Britelite: Most budget-friendly
- Britannia: Best finance options
- Safestyle: Most eco-friendly
Anglian
- Price range: From £250 to £910 per window
- Guarantee options: 10 years on parts and labour, 15 years on gas-filled units
- Energy rating: A to A+ for double-glazed windows
- Trustpilot score: 3.8/5
Anglian takes the top spot for the best overall double glazing windows company. With 50 years of experience and half a million installations carried out annually, Anglian is a household name, and it provides great value to its clients.
The company offers six window styles (casement, sash, flush, bay, tilt and turn, and cottage) and three choices of materials (aluminium, wood, and uPVC). Plus, Anglian has a variety of additional features available such as obscure or security glass. There are even decorative styles like bevelled and etched glass, ideal for customers who are trying to create their own unique style.
Wooden windows are rated A for energy efficiency, and for aluminium and uPVC windows you can choose either A, A+, or even A++ for triple-glazed options. Each rating offers good thermal insulation and savings on your energy bills.
Backed by organisations and accreditations such as Made in Britain, the British Fenestration Rating Council (BFRC), the Fenestration Self Assessment Scheme (FENSA), the Glass and Glazing Federation (GGF), TrustMark, Secured by Design, the British Standards Institute (BSI), and BSI Kitemarks, the double glazing offered by Anglian lives up to quality expectations. And Anglian’s 15-year guarantee on gas-filled units is slightly better than the 10 years offered by its competitors.
What homeowner reviews say
A Trustpilot score of 3.8/5, based on 26,493 reviews, highlights Anglian as a reliable and trusted brand. However, most of the negative reviews refer to installation issues, so be sure to contact Anglian to look at their team’s work quality and check out their reviews before making a decision.
Cost
Anglian offers competitive prices with a low rate monthly finance scheme at a representative 9.9% APR over 36 months. Costs can vary based on factors such as style, type of glass, and any additional features selected. Below are the estimated costs based on frame material.
| Frame material | Average price per casement window |
|---|---|
|
uPVC |
£250–£570 |
|
Aluminium |
£500–£605 |
|
Wood |
£845–£910 |
What we like
Anglian offers a great solution for double glazing windows in terms of price, quality, styles, and guarantee period. However, its payment plan options aren’t as good as those offered by Everest or Britelite. Overall, we recommend Anglian to clients who are style conscious and want more control over the design of their new windows.
Read our full Anglian double glazing windows review.
Everest
- Price Range: From £500 to £2,460 per window
- Guarantee options:
- 20-year guarantee against discolouration of white uPVC
- 25-year guarantee on aluminium finish
- 30-year guarantee against rot and fungus on timber windows
- 10-year guarantee on windows, including hinges, locking, and installation
- Energy rating: A+ double glazed, A++ triple glazed
- Trust pilot score: 4.3/5
Founded in 1965, Everest is one of the UK’s oldest double glazing window manufacturers, known for its high-quality products and for providing the longest guarantee periods. Everest’s double-glazed windows have an A+ rating for energy efficiency, meaning better energy bill savings for the homeowner. Notably, it even offers A++-rated triple-glazed windows.
Everest products come in a range of styles, including casement, sash, and tilt and turn, and in materials such as wood, aluminium, and uPVC. Additional features such as obscure glass, noise reduction glass, various handle designs, and locking systems are also available, so you’re highly likely to find something to suit your styling needs.
Quality is assured by industry-leading accreditations such as BSI and BSI Kitemarks, TrustMark, Made in Britain, Quiet Mark, Secured by Design, and the British Fenestration Rating Council (BFRC).
What homeowner reviews say
Everest has a reputation for providing quality products and excellent customer service, earning the company a 4.3/5 score on Trustpilot, based on 11,696 reviews. However, some customers have reported issues with the sales team trying to upsell features, so be sure to have a clear idea of your project before contacting Everest. As complaints of poor installation quality were also highlighted, we advise obtaining details about the local installation team in advance.
Cost
Everest is one of the most expensive manufacturers, but it does offer secured lending options ranging from £1,000 to £250,000, with flexible lending periods of up to 25 years.
The prices given below can vary based on several other factors such as style, type of glass, and frame colour.
| Frame material | Average price per casement window |
|---|---|
|
uPVC |
£500–£1,230 |
|
Aluminium |
£625–£1,540 |
|
Wood |
£750–£1,845 |
What we like
Everest offers a high-quality product, supported by industry-leading organisations. It may be more expensive than competitors such as Anglian and Britelite, but it’s worth the investment due to the guarantees and style options they offer. We recommend Everest to customers who aren’t too picky about the cost and want high-quality service done with less hassle.
Read our full Everest double glazing windows review.
Britelite
- Price Range: From £160 to £1,050 per window
- Guarantee options: 10-year transferable guarantee
- Energy rating: A+ double glazed, A++ triple glazed
- Trustpilot score: 4.1/5
With more than 50 years of experience in double glazing windows since its inception in 1970, Britelite offers the most cost-effective pricing of the companies we reviewed, while achieving an A+ energy rating. This ensures good thermal insulation and more savings on energy bills.
Offering four window styles (casement, sash, tilt and turn, and traditional residence) and three options for materials (uPVC, composite, and aluminium), Britelite has a limited selection compared to some other brands. Additional features are also limited, with your only choices being in terms of colour and handles.
Britelite provides a high-quality product, with industry-leading certifications such as Made in Britain, FENSA, TrustMark, GGF, BSI, BFRC, and Which? Trusted Trader. Britelite also offers a 10-year transferable guarantee, which can be passed on to the new owners when you sell your home.
What homeowner reviews say
With a score of 4.1/5 on Trustpilot, based on 1,237 reviews, Britelite scored well in customer feedback in terms of product quality. Still, reviews were mixed, with customers complaining about the poor after-sales service and the standard of the installation. We therefore recommend you get all the necessary details about the installation process and after-sales services from Britelite during the quotation stage to avoid disappointment.
Cost
While offering the lowest prices, Britelite also provides a monthly payment finance option and a buy-now-pay-later scheme, backed by Novuna Finance.
Below are the average costs for Britelite’s double-glazed windows, based on frame material.
| Frame material | Average price per casement window |
|---|---|
|
uPVC |
£160–£450 |
|
Aluminium |
£500–£605 |
|
Composite |
£475–£625 |
What we like
If you don’t mind the limited options and styles available, and price is your primary concern, then Britelite is your best option. But don’t let the low cost fool you—with an A+ energy rating backed by industry-recognised organisations, you can rest assured of the quality.
Read our full Britelite double glazing windows review.
Britannia
- Price range: £250–£605 per window
- Guarantee options: 10-year transferable guarantee
- Energy efficiency rating: A or A+ on double glazing
- Trustpilot score: 3.5/5
Covering the south and south-west of England, Britannia has been installing double glazing windows since the early 1980s. Offering a wide range of styles and materials, the family-run company manufactures its own products in the UK, allowing homeowners to customise their window designs. Accredited by Secured by Design, the official police security scheme, Britannia handpicks local installers to carry out its projects.
Britannia offers a range of payment options with flexible payment terms, making it an attractive choice when it comes to replacement windows.
What homeowner reviews say
With a 3.5 Trustpilot score, customers generally regard Britannia’s services as good, commenting on the efficiency and politeness of the installers, and high quality of the products. Many return for further windows or doors and are happy to recommend the company to others. However, many of the negative reviews are related to work done by local partners of Britannia, with some customers reporting their windows were the wrong size when it came to installation. Others have said it can be difficult to reach a resolution with the company if something goes wrong after installation or during the warranty period.
Cost
Britannia’s price points are not displayed on its website, allowing the company to quote customers directly. However, from price comparison sites and customer reviews, we determine that it generally compares favourably with Anglian and Safestyle.
| Frame material | Average price per casement window |
|---|---|
|
uPVC |
£250–£500 |
|
Aluminium |
£500–£600 |
What we like
Offering affordable style and quality double glazing windows, there’s a lot to recommend Britannia. A transferable warranty is great if you’re selling your home, or buying a property with new double glazing. The range of finance options make Britannia ideal for customers who want to spread the cost of replacement windows.
Read our full Britannia double glazing windows review.
Safestyle
- Price range: From £250–£1,050
- Guarantee options: 10-year standard guarantee (excluding handles)
- Energy rating: A-rated for double-glazed windows
- Trustpilot score: 4.1/5
One of the largest double glazing windows companies, Safestyle has made more than £100 million in replacement window sales since it started in 1992. Although it only offers uPVC windows, the company makes up for that in the number of styles and wood-effect finishes available.
Safestyle is committed to delivering a sustainable service, buying back old windows from customers and recycling them at its dedicated centres. Every month, Safestyle recycles nearly 700 tonnes of glass, metal, and uPVC, and plans to fully recycle its waste by 2024.
Offering value for money and flexible payment options, Safestyle has a reputation for delivering a good service.
What homeowner reviews say
Safestyle has a 4.1 rating on Trustpilot, with 80% of customers awarding it four or five stars. Many mention the punctuality and professionalism of the installers, great communication, and a smooth installation process. However, some customers have given negative reviews due to the company’s after sales service, saying they have had issues with getting problems rectified once the installation is complete. Other reviewers point out “pushy” sales tactics in the quote process.
Cost
Safestyle windows are given mid-range price points, but by offering a like-for-like price match guarantee, you could install Safestyle quality at budget prices. As the company focuses on uPVC double glazing windows, comparing price points with other major installers is difficult, so we’ve looked at the average cost for each main window style.
| Window style | Cost |
|---|---|
|
Casement |
£250–£570 |
|
Sash |
£500–£1,000 |
|
Bay |
£400 per bay section |
|
Tilt and turn |
£400–£650 |
What we like
It’s encouraging to see a successful company delivering on its commitment to sustainability, and this is a huge plus point for Safestyle. It also has a good Trustpilot score, demonstrating that the company is ticking boxes all round. We think the like-for-like guarantee is a great opportunity for customers to enjoy high-quality double glazing windows without the cost.
Read our full Safestyle double glazing windows review.
Styles of double glazing windows
| Double glazing window style | Description | Suited to |
|---|---|---|
|
Casement |
Side hung like a door but can open from the bottom or top |
Contemporary but also very versatile and suit any home |
|
Sash |
Two panels that slide up and down, or one fixed and one sliding |
Period—Victorian, Georgian, or Edwardian |
|
Bay |
Projects out from the wall with extended brickwork to the ground |
Contemporary or period |
|
Tilt and turn |
Side hung to swing fully open and bottom hinges that allow tilting inwards for ventilation or safety |
Contemporary |
|
Bow |
Projects out from the wall without any brick extension supporting it |
Contemporary or country home |
Casement windows offer the most versatility when it comes to style, making them the most popular option for most homeowners. At their most basic, casement frames have two windows opening outwards with a vertical post in the centre of the aperture they close against. French casements remove the central post, making them perfect for an uninterrupted view outside, while many people choose a style that incorporates struts set within the window itself–known as Georgian bars—creating a panelled appearance.
Another popular design is the sash window, often called a sliding sash. The window divides in half horizontally, with one part—usually the lower—sliding open to create the aperture. Many manufacturers incorporate a tilt mechanism, enabling the window to be tilted, rather than slid, open.
Frame materials
Manufacturers of double glazing windows offer a range of frame materials, each with its own pros and cons.
| Frame material | Upsides | Downsides |
|---|---|---|
|
uPVC |
Low cost Highly durable Low thermal conductivity |
Limited customisation options White uPVC can discolour over time |
|
Timber |
High aesthetic appeal Low thermal conductivity Highly durable if cared for |
Highest price band High maintenance |
|
Composite (timber for the interior frame/uPVC or aluminium for the exterior) |
Highly durable Low maintenance Low thermal conductivity |
Mid-range price band Limited manufacturers |
|
Aluminium |
Highly durable Low maintenance Recyclable |
Can corrode in coastal properties High thermal conductivity Prone to condensation |
Window furniture
Handles and other window furniture is available in several styles to suit a range of properties. uPVC windows tend to have either espag or cockspur handles fitted as standard. Very similar in appearance, a key or button lock is typically incorporated into the handle.
Other styles include cast iron or brushed chrome monkey tails, traditional brass, or bulb-ended handles. These are more suited to timber or composite frames and often come with matching stays.
How to select the right double glazing windows company
New double glazing windows are a popular home improvement feature and can help you create a stylish, efficient living space. Still, there have been reports of companies providing poor installation, damaged products, and even damage to customers’ homes. Before choosing a double glazing company, you might want to consider the following factors.
1. Experience
Always choose a double glazing company with several years of experience. The longer they’ve been around, the more likely you are to get expert service at a reasonable price.
2. FENSA accreditation
To save time and money, check that the double glazing company you hire is registered with FENSA. This means you don’t have to register your window installation with FENSA yourself, and you’ll know that the company has been thoroughly vetted.
3. Customer testimonials
To make an informed decision, it can be helpful to read the feedback left by other customers about the quality and service of a supplier. How the company reacts to negative feedback can also give you an idea of whether or not this is the right choice for you.
4. Security features
Poor security features on your windows will make you vulnerable to break-ins. If you want to ensure the safety of your home, choose a double glazing company that includes options such as multi-point lock systems on its windows.
5. Guarantee periods
All double glazing companies must provide a minimum 10-year guarantee on materials and labour, according to building regulations, but bear in mind that some companies offer longer periods.
6. Styles and feature options
Many companies offer different styles, materials, glass types, and additional features. Do some research on the suppliers’ options and have a good idea of what you envision for your project—the best way to avoid getting sold features you don’t need.
What are my rights when buying double glazing windows?
Generally, home improvements, such as a double glazing installation, go smoothly when experienced, knowledgeable professionals carry them out, but sometimes things go wrong. Maybe the project isn’t finished on time or to the high standards you rightly expect, so what can you do if you encounter a problem?
As a customer, you do have rights in the unlikely event that you’re not happy with the service you’ve received, and these start from the moment you agree to a contract.
Your contract should include all the details of the project, so check it over carefully for the following before signing:
- Details of the project
- Details of the windows, including number, sizes, materials, and styles
- The total price, including installation and VAT
- The start and finish dates
Can I cancel my installation beforehand?
According to Citizens Advice, your contract should include details of your ‘cooling off’ period. This allows you to cancel any agreement made over the phone, online, or in person at your property at least 14 days after you’ve entered into it. If you signed the contract at the installer’s premises or the windows are specifically designed for your property and cannot be resold, you lose the right to cancel.
What if I discover issues after my windows are installed?
All professional installers should have a FENSA-backed guarantee, which covers you in the event of a problem with your double glazing windows, or the installation.
The Consumer Rights Act 2015 offers a high level of protection from faulty goods or services and ensures that your new windows, the installation, and property are in good order.
Your replacement windows should be as described, and the installation carried out using all reasonable care and attention. If this isn’t the case, your installer has a duty of care to address your concerns by replacing or repairing the windows and rectifying any damaged property.
Our recommendation
Style is only one of many factors to consider when selecting a double glazing window company. Energy efficiency and security are also important. When making your choice, it’s a good idea to look at the company’s certifications, as well as checking the credentials of the team that will actually be installing the windows. Keep these key aspects in mind as you make your decision.
Double glazing windows FAQ
What are double glazing windows and how do they work?
Double glazing windows are a sealed unit made from two panes of glass with a spacer bar creating a gap between the panes. This space is usually filled with argon gas, which is a poor conductor of heat, thereby increasing the window’s insulating properties. In the winter, the gas layer prevents the heat inside your home from transferring to the external pane of glass and escaping to the outside. In the summer, it can prevent the heat outside from getting into your house, but we’ll touch on that later.
How long do double glazing windows last?
The life span of double glazing windows depends on the material they’re made out of and how well they’re maintained, but in general you can expect them to last at least 20 to 30 years on average. Some windows, such as those with timber frames, can last upwards of 50 years or more if they’re looked after.
Do double glazing windows keep the heat out in summer?
Just as double glazing windows can keep the heat inside your home during the winter, they can also keep the summer heat out, though this comes with a caveat. Double glazing windows help to foster something called solar gain, whereby heat energy from the sun’s rays becomes trapped inside your house. While this helps to reduce your reliance on central heating in the winter, it can lead to uncomfortable temperatures during heatwaves. For this reason, it’s important to keep your curtains or blinds closed during daylight hours in the summer to prevent solar gain and allow your windows to keep cooler air inside your house.
Are double glazing windows worth it?
While replacement windows come at a significant cost, the energy-saving benefits of double glazing make it worth the investment. According to the Energy Saving Trust, upgrading to A- or A+-rated double glazing windows can save you £195 to £235 per year on your energy bills versus single glazing.
Can double glazing windows stop condensation?
Double glazing can help prevent a build-up of condensation thanks to its insulating properties. Because the internal pane of glass stays closer to room temperature and does not get as cool as the external temperature, condensation doesn’t have much chance to form on the glass. This in turn helps to stop the formation of mould, which is a common struggle for homes in the UK.
What if condensation forms between the panes of glass?
Because they are a sealed unit to prevent cold air from getting into the gas-filled chamber, your double glazing windows should never have condensation between the panes of glass. If this happens, it means the seal is broken and not functioning properly. You should call your installer to inspect the window and determine if the double glazing unit needs to be replaced.
Can double glazing windows be repaired?
Yes and no. Due to the fact a double glazing window is a sealed unit, you cannot replace just one pane of glass if it is broken—the entire unit must be replaced. This can usually be done without changing the entire window frame, but it is best to call your installer to find out what work needs to be done. If the seal is malfunctioning within the first few years after your installation, it could be a manufacturing defect.
Do double glazing windows reduce noise pollution?
Yes. Double glazing windows are ideal for homes near busy roads, railway lines, airports, or other noisy areas, as they have sound-dampening properties that can keep outside noise out of your house. This is especially true if you opt for acoustic glass, which is made of two or more sheets of glass bonded together with an invisible film that further dampens sound waves as they pass through the glass.
How we chose the top double glazing windows providers in the UK
To compile this guide, we conducted research and compared some of the top rated double glazing window fitters in the UK to help us offer an honest and informative review. In this research, we examined product guarantee, cost, customer reviews, expert opinions, design, and style choices. All of this enabled us to form our own opinion of each company’s windows and their installation process.