The seven best double glazing companies in the UK

• We researched over 200 of the UK’s FENSA-certified double-glazing companies
• Of these, we rated the best seven firms against 11 key criteria
• Criteria included warranties, accreditation, and reviews from real customers
• Read our guide before choosing the best double-glazing company for your home

Double glazing is one of the best ways to improve your home’s energy efficiency and reduce energy bills. But as our article on double glazing prices reveals, it costs upwards of £10,000 to replace all the windows on a typical house, so you’ll want to hire the best company for the job.

To help you get your money’s worth, we set out to find the best double-glazing companies in the UK. After analysing current information about hundreds of firms, including big names such as Everest, Anglian, and Safestyle, as well as dozens of regional providers, we chose the best seven. We review them below.

We prioritised installers certified by FENSA (Fenestration Self-Assessment Scheme) and the BFRC (British Fenestration Rating Council). Still, our judging criteria also included warranties, choice of windows and other products, experience, and customer service. Crucially, all the companies in our list below receive good customer feedback.

See our methodology for more information on how we selected companies for our rundown.

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The best double-glazing companies at a glance

Here’s a quick look at how the UK’s seven best double-glazing installers compare on window guarantees, experience, and geographical coverage.

Best choice of windows: Anglian

After several key mergers, Anglian is now the dominant firm in doubling-glazing in the UK. For this reason, it should come as no surprise to find it offers the best range of windows in the UK right now.

If you’re keen to upgrade your beloved sash windows or unusual wood frames with made-to-measure timber, uPVC, or aluminium replacements, this is the company to try first.

Anglian Home Improvements, to give it its full name, launched just after Everest in 1966 and offers all the standard window types, including casement, bay, tilt & turn, and sash. You can also opt for custom shapes, etched and obscure glass in assorted designs, and cottage windows that meet tight rules in conservation areas and listed buildings.

Anglian even lets you order bespoke blinds to match your windows.

The website has some excellent free tools to help you visualise various window types on your home, plus an inspiration gallery and guides to home renovation. Anglian’s site is less transparent on pricing than Everest’s, and its timber frames can get very pricey, but its quotes are said by some customers to match or undercut other companies.

The company receives a slightly mixed score of 3.9 from customers on Trustpilot, although they have a huge volume of reviews – nearly 35,000 at the time of writing, with close to 60% at the maximum five stars. Recent reviews include a large number of happy customers as well as some with concerns about customer service or the sales approach.

What Anglian’s customers say

“They gave the best quote of five other companies, and one company couldn’t even match Anglian before they made some discounts. They fitted two weeks ahead of schedule, and the installer knew exactly what he was doing” – Martin Spaven, August 2024

“I had some issues to manage as windows were going in a new hipped roof, but Anglian bent over backwards to be flexible and work around the roofer. The windows were installed to a high standard and look very good” – Claire Briault, August 2024

Best one-stop shop: Everest

“Fit the best: Everest!” went the legendary 1980s TV advert that made Everest the best-known double-glazing company in Britain. Decades later, Everest still has the strongest brand recognition on this list. Does it deserve its high profile, especially now that it’s part of the Anglian family?

We think it does. In its original form, Everest is the most experienced firm of its kind, having begun to produce and fit aluminum secondary glazing in 1965. It later added uPVC and timber frames across the full range of window styles.

The company has been through a couple of incarnations, having gone into administration in 2020 (when it rose again as Everest 2020) and then in April 2024 before the takeover by Anglian. It also offers doors (including garage doors), conservatories, and roofline products such as guttering, adding to a convenient one-stop shop when renovating your home.

We found Everest’s website particularly easy to navigate, with clear information about guarantees, financing, and prices. Unlike companies on this list, Everest displays price estimates online rather than forcing you to submit details for a quote.

Prices start at £600 per uPVC casement window and rise to more than £2,000 if you opt for extras such as A++ rated triple glazing, custom frame colours, and a wealth of security features such as “GrabLock” locks. These extras can boost the value of your property and reduce your insurance premiums, but they are a sizeable upfront investment.

Everest receives a pretty average score of 3.8 on Trustpilot, with some concerns about customer service.

Read our in-depth Everest review

What Everest’s customers say

“Kept us well informed every step of the way. From first meeting to completion of work all involved were courteous and helpful, and answered any questions we had. Fitters were very efficient and treated us and our home with respect” – Mr and Mrs Clark, April 2024

“Had secondary glazing installed for sound proofing and its made a big difference. Windows all look great, fitted well, had some very minor issues they were quick to come in, inspect and resolve with very little hassle” – James, March 2024

Best for sustainability: Safestyle

Following its fall into administration in October 2023, Safestyle is now part of the Anglian Home Improvements family.

The Safestyle range isn’t as broad as Anglian’s or Everest’s, and its windows are all uPVC rather than aluminium or timber. But it also offers doors and roofline, and its windows cover a decent range of styles, including sash, leaded, etched, and French windows.

Safestyle’s commitment to sustainability genuinely impressed us. The company recycles your old windows and re-uses what it can to make new windows and other products. Every month, it recycles tonnes of used uPVC into drainpipes and plastic decking, turning wood into pellet fuel for biomass heating systems.

Like Anglian, Safestyle doesn’t publish any prices upfront. However, it offers a quote-match promise and a guarantee of up to 15 years on its windows.

Regarding customer reviews, it receives a relatively average score of 3.9 on Trustpilot, with some of the most recent reviews since the takeover by Anglian raising concerns about customer service and quality.

Read our in-depth Safestyle review

What Safestyle’s customers say

“One workman arrived who was polite and respectful. He proceeded to remove five windows, fit the new ones and all their trim, clean (the) wreckage up all by himself… gone before dinner with no breaks. Brilliant!” – Christine de Hamel, July 2024

“The windows and doors fitted all look great and are really good quality. We liked the fact they are made in the UK too” – Tamsyn, October 2023

Best for security: First Home Improvements

First Home Improvements will make any window you want in any style, as long as it has a uPVC frame. There are no wood frames here, alas. The company also installs conservatories, porches, and doors, including composite front doors, which you can plan online using the website’s Door Designer tool.

All these products will enhance the security of your home, but First Home Improvements goes the extra mile by including Yale’s patented Blade Lock system – which it claims is “the strongest, safest and most secure lock on the market” – with all its windows and doors.

First Home Improvements guarantees the entire window, including locks and frames, for an unusually generous 12 years, compared with the typical 10 years for anything other than the sealed glazed unit. Customer reviews were among the best, up to an “excellent” 4.6 average on Trustpilot.

What First Home Improvements’ customers say

“The installers turned up on time and were friendly, getting on with the job immediately. They worked non-stop until it was complete, doing a very professional job including taking away the old windows” – John Adams, August 2024

“When installation was complete, all window locks and opening/closing functions were explained thoroughly. A very good job done very well” – PB, August 2024

Best on a budget: Britelite Windows

Britelite is another company that doesn’t publish prices upfront. Still, when we asked for a free quote, we were pleasantly surprised by the result. A uPVC casement window costs around half the price of Everest’s equivalent window. What makes this even more impressive is that all windows come with a 10-year guarantee that’s fully transferable if you sell your house.

We haven’t taken the quote process any further, so it’s hard to judge whether you get what you pay for with Britelite’s windows. However, customer reviews mention “superb quality” and say the windows “stay looking good for a lifetime.”

Customer reviews aren’t as glowing for Briteline as for other companies on our list (notably First Home Improvements, Clearview, and Scottish company CR Smith). That said, it still scores a respectable 4.5 on Trustpilot, praising the company’s quick responses and professional approach.

What Britelite’s customers say

“Luke and Paul came to install my bay window. Clean, efficient, very friendly and finished the job on time too. Definitely recommend to anyone wanting windows that last and stay looking good for a lifetime” – Ana Partlett, July 2024

“The workmen were clean and efficient, they worked hard, were diligent and tidied up everyday they were in the house. The windows are superb quality” – Liza Stubbs, August 2024

Best for 3D previews: CR Smith Windows

Many double-glazing companies we researched offer 3D preview tools to help you visualise how your new windows, door, or conservatory will look in your home. But none offer quite the design process that Scottish firm CR Smith does.

During CR Smith’s “virtual appointment,” the consultant uses photos and measurements of your property to create an immersive preview of how your home’s windows or conservatory will look. They talk you through the options available and suggest alternatives if you’re unhappy.

The company provides and installs Lorimer windows in many different finishes and styles. You must choose between uPVC (the cheapest) and timber (the most expensive) rather than opt for anything in between. If you go for those gorgeous wooden frames, you can at least spread the cost via the company’s finance options.

With customer feedback averaging a superb 4.9 on Trustpilot, we can only find one significant downside with CR Smith Windows: you have to live in Scotland to use them. Another reason to move north of the border, perhaps?

What CR Smith’s customers say

“Fantastic service from start to finish. We were kept informed every step of the way. The installation team were professional and friendly throughout, hardly knew they were there. Extremely happy with our new window, great quality and value for money!” – KW, August 2024

“We wanted a company that we could trust and that’s what we got. The service from start to finish was great, the team are easily accessible by phone and email which made planning simple” – Rachael, July 2024

Best for warranty: Clearview Home Improvements

The average double-glazing guarantee is around 10 years, roughly a third of the expected lifetime of a window, but Clearview doubles that with a 20-year warranty. This market-leading pledge is one of the reasons the company has won the industry’s G Award two years in a row.

Clearview’s website and customer feedback have a strong focus on living spaces, including conservatories and extensions rather than windows. Still, the company offers a decent range of window styles, albeit only in uPVC and aluminium. 

As with CR Smith, the key limitation with Preston-based Clearview is geographical coverage: North West England, in this case. However, this is only a downside if you don’t live there.

If you do, you will benefit from the company’s local knowledge and teams – as confirmed by the firm’s excellent customer feedback, adding up to a strong 4.5 score on Trustpilot.

What Clearview’s customers say

“Each stage ran like clockwork with no delays including when the roof and windows were fitted in a mini monsoon… Not only thrilled with the end result but extremely impressed with the individual and collective work, and definitely the end product” – John Barnard, August 2024

“Clearview were excellent from start to finish, from the initial design stage to final completion. We encountered delays outside their control, and they were very patient with us until we were in a position to proceed” – Keith Mcguire, April 2024

Our methodology explained

Our team of four researchers spent 28 hours investigating double-glazing companies to find the top seven firms across the country. Here are the key criteria we used to whittle the list down to seven:

• Warranty – windows need a solid warranty to protect them from unavoidable wear and tear. The average double glazing warranty is 10 years, with only the sealed units typically guaranteed for longer, so we prioritised companies offering more extended warranties.
• Choice – one window size does not fit all houses, and not everyone wants boring white uPVC. So we looked for companies that offered a wide range of materials and styles and made all their windows to measure.
• Customer feedback – we couldn’t test our best double-glazing companies by hiring them, so we turned to our most trusted sources: customers. We analysed nearly 1,000 verified customer reviews via TrustPilot and Check-a-Trade and prioritised companies with many positive reviews.
• Customer service – we gave companies credit for responding quickly and graciously to feedback and offering easy ways to get in touch. Some of the companies we considered for this article had customer service email addresses that immediately “bounced back,” so we decided not to include them.
• Accreditation – don’t even consider hiring a window installer in England and Wales who can’t give you a FENSA certificate because it will make your house harder to sell (take it from one who’s experienced it!). We also prioritised companies accredited by the TrustMark and the Glass and Glazing Federation.
• Industry experience – companies with 50 years of experience aren’t necessarily better than those with five years of experience. Still, if a firm has a long and successful history of providing and fitting windows, you can be reasonably confident that it knows its stuff.
• Security – double glazing naturally enhances the security of your home, but we wanted to see what else companies could offer for extra peace of mind and potentially lower insurance premiums. For example, security glass, complex locking mechanisms, and break-in guarantees.
• Previews – ideally, you want to know how windows will look in your home before you commit, so we looked for clever preview tools such as 3D virtual consultations that give customers a realistic idea of the finished job.
• Affordability – we didn’t just look for the cheapest windows overall but instead considered a balance of cost, quality, and transparency about pricing.
• Finance options – following Anglian’s purchase of Everest and Safestyle, there’s less competition in financing for home improvements, and interest rates have risen in recent years. We looked for companies offering easy, flexible repayments.
• Geographical coverage – we awarded star ratings for wide UK coverage because there’s little point in raving about a double glazing company whose locality means you may be unable to use them. That said, we recommend considering installers who are local to you. They will benefit from local knowledge and may be able to book you more quickly. Use our free double-glazing quote tool to find installers near you.

Next steps

By now, you’ll have a good idea of which double-glazing installer is right for you. The next step is to find the best deal – and that’s where we come in.

Enter a few details about your home on our window quotes form, and let us do the rest. We’ll pass on your details to our hand-picked professional installers, who will then get in touch to let you know their best prices. You have no obligation to take them up on it.

If you want to let some light in through a window in your roof, look at our guide to buying skylights and rooflights.

Summary

• We reviewed over 200 FENSA-certified double-glazing companies in the UK to identify the top seven installers.
• Our evaluation focused on 11 key factors, including warranties, customer feedback, product range, and accreditation.
• From national leaders like Anglian and Everest to regional specialists like CR Smith, we highlighted the best choices for different needs, including energy efficiency, security, and budget.
• Our guide reviews each company’s strengths and weaknesses, backed by verified customer feedback and industry expertise.
• Use our window quotes tool to connect with the best double-glazing professionals and find competitive pricing for your home improvement project.

Written by

Jane Hoskyn Contributor

Jane is a freelance journalist and copywriter who has spent many years reporting on the benefits of technology for consumers, businesses, and our planet. She currently writes on consumer issues and sustainability for The Guardian, Expert Reviews, and The Eco Experts. After starting her career in local papers and the music press, Jane found a professional home in magazine features. She was a regular BBC Radio guest during her time as Features Editor on IPC's Web User, then took on similar roles at Broadcast and Computeractive. Jane has also written for titles as diverse as IT Pro and Cosmopolitan and created online content for leading brands. London-born Jane now lives with her husband and their cat in her old university city of Southampton, where she enjoys running, photography, and spotting pigs in the New Forest.

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Reviewed By

Christopher McFadden Contributor

Christopher is an Environment, Health & Safety (EHS) specialist with extensive experience advising consumer and trade clients on energy efficiency and sustainability. With a Master's in Earth Sciences from Cardiff University, Christopher has attained professional energy and sustainability auditing qualifications and various postgraduate certificates and diplomas. He is a qualified and accredited Level 3 and Level 4 non-domestic and domestic energy assessor, a Green Deal assessor, and a Practitioner member of the Institute of Environmental Management and Assessment (IEMA). He also recently qualified as a level 5 Retrofit coordinator. In addition to his day job, Christopher has also honed his skills as a STEM writer for several well-known online publishers, sharing his knowledge and passion for science, engineering, and dinosaurs with millions of readers around the world.

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