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Best double glazing companies


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Put us to the test

Our Test Labs compare features and prices on a range of products. Try Which? to unlock our reviews. You'll instantly be able to compare our test scores, so you can make sure you don't get stuck with a Don't Buy.

We reveal what double glazing customers think of Everest's service and products, based on the results of an independent Which? survey.

Our survey of more than 2,000 double glazing customers reveals what they really think about big-name brands Everest, Anglian and Safestyle, as well as local independents. You can use the results of our research to find out which double glazing company is best. 

The results of our survey reveal vast differences between companies. Customers raved about our top-scorer, which achieved a score of 86%. While the bottom-rated brand got just 56% - 30 percentage points less.

Log in now to unlock all the ratings below, including customer comments about Everest. If you're not a member, you can get instant access to this, and thousands of reviews, for a trial subscription to Which?.

You'll also gain access to our page on the average price of double glazing, which will help ensure you don't pay too much for your double glazing, and our tips on how to side-step sale tactics. 

If you want to compare all the double glazing brands in our survey, go to the best and worst double glazing companies.

How did Everest score in our double glazing survey?

The table below shows how Everest's customers rated it for a variety of important areas of the buying and installation process.

Everest survey results
Sales or installation factors Which? rating
Overall customer score
Knowledge of staff
Clarity of documents
Customer service
Quality of products
Value for money
Installers keeping to arranged times
Knowledge and helpfulness of installers
How well the installers communicated
Mess during and after installation
Quality of installation
After sales support

We asked Everest's customers to tell us how satisfied they are with the brand and whether they would recommend it to a friend. We then use this data to calculate our customer score. 

We also asked them to rate elements of the buying and installation process. This includes the knowledge of staff (both sales and installers), quality of products and installation, and clarity of documentation - such as the contract. These ratings help you understand which elements the companies in our survey succeed on, and where they fall down. 

Everest customer comments

In addition to our ratings, we asked customers to give us any comments on their experience with the company. You can reveal these comments and find out what Everest's customers really think of it by logging in. If you're not yet a Which? member, you can sign up for a trial subscription to Which?.

Signing up or logging in will also give you access to:

Everest double glazing

Flick through the images below to see some examples of the types of double glazed windows and doors Everest provides, and read on below to learn more about its services.

What does Everest offer?

Areas in the UK Everest covers: England, Scotland and Wales, but not Northern Ireland.

Types of windows: casement, sash, tilt and turn, dual turn, in uPVC, timber and aluminum. It offers double glazing, triple glazing and secondary glazing options.

Types of doors: entrance doors, bi-fold, French, patio in uPVC, timber, aluminum and composite.

Window energy ratings: A+ rating as standard for uPVC casement windows. Triple glazing is A++. It doesn't state the energy ratings for other double glazing.

Window and door guarantees: 10-year guarantee on all new windows. Windows and doors of different materials can have different additional guarantees, such as 30 years against rot and fungus on timber windows and doors. Some have a lifetime guarantee. These can be switched to a different owner, but at a cost.

Other services Everest offers: conservatories, garage doors, flat roots, roofline/rooftrim (such as guttering, bargeboards, cladding etc), driveways, artificial grass and security alarm systems.

Competent Persons Scheme: accredited by Fenestration Self-Assessment Scheme and Glass and Glazing Federation, which means Everest installers can self-certify that the double glazing is compliant with building regulations.

To find out more about the different types of windows and energy ratings, go to double glazing explained.