Getting the best windows and doors – a practical guide

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Nick Dardalis

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As a potential buyer of new windows and doors, many product choices and conflicting sales messages can often seem overwhelming. There are over forty brands of bifolding and sliding doors and numerous window brands and types. Every salesperson or glazing company claims to offer the “best” product. But what does “best” really mean? How can you understand whether the best windows and doors being offered are right for you?

Buying windows and doors for your project may feel like a minefield. In this article, we will give you some insight and knowledge about the windows and doors you need to buy, helping you make sense of what you are being told and arming you with the right information to ask any door and window supplier. We will also help you understand more about the best windows and doors and the glazing industry in general.

Do the best windows and doors exist?

In the context of windows and doors, “best” can be subjective. What works best for a modern loft conversion or contemporary home will not suit the traditional glazing required at the front of a Victorian terraced house. Therefore, the best windows and doors significantly depend on the nature of the project and personal preferences.

The term “best” can often be misleading when used by salespeople or in marketing campaigns, implying that components of one brand are inherently superior to another. Whilst this is true in some respects, it is incorrect in others.

What is true is that some of the best windows and doors are engineered better. They can be designed in such a way that they have more technical capability, they can meet or be enhanced for specific use cases and come with more options in terms of function. If none of these more advanced features is necessary for your project, these are probably not the best windows and doors for you.

aluminium crittall-style doors in a new dining room extension supporting best windows and doors article.

When you encounter a salesperson dismissing a brand outright, it’s wise to be sceptical. There isn’t a ‘bad’ brand because most windows and doors are tested to the same standards and have similar aluminium, glass, and coatings specifications. The quality of a window or door often boils down to its manufacturing and installation.

There are four areas where the standard and the best windows and doors are very similar. Moreover, these are the areas where you may be told one product is superior.

The quality of the aluminium itself

Whether low-cost or the best windows and doors, each must meet certain basic standards and specifications. Aluminium is widely used in various consumer products and comes in many grades. The aluminium profiles for windows and doors are always of a quality suitable for ‘architectural use’. So if your salesperson says their windows have the best quality aluminium or premium grade aluminium, ask them to explain how and why.

The quality of window and door colours

Then we come to the powder-coated colour finish on aluminium windows. Who applies the colour matters a lot. The door and window system company usually has its own coating plant. Alternatively, they may subcontract the work to a network of very specialist and quality-assured colour applicators specialising in coating aluminium extrusions for doors and windows. The takeaway here is that if you are told the colour coating on an aluminium window is better than the competition, this is unlikely to be completely true, although it is true that some brands offer a marine-grade coating as standard, especially on the best windows and doors. This paint coating is thicker and more durable than the standard coating. However, marine-grade sales messages can be misleading, as explained in this article.

The glass quality in your new windows and doors

The significant component of any window is glass. With glass sheets being produced by major names such as Pilkington Glass, Saint-Gobain and others, again, it is unlikely someone’s glass is better than the competition as there are substantial standards applicable to glass, depending on how it is used and its location. Once again, be sceptical of companies claiming the glass in their windows is superior to others.

Security, weather performance and energy-efficiency

There is no question that security, weather performance, and energy efficiency are three of the most important features of the best windows and doors. It is also true that these performance credentials do vary from product to product. The testing of windows and doors can be quite a complicated subject to get your head around, made worse by the complexities of the testing process itself and what products specifically are submitted for testing.

A good example is doors. An outward-opening patio door may have been tested and has PAS 24 or Secured by Design, but an inward-opening model has never been tested. But your salesperson tells you that the brand you are looking at has Secured by Design certification and accreditation. You can check this on the Secured by Design Website by searching for the system company. If you don’t see it, you can contact us or get back to your salesperson and ask for clarification on what this means for the products you are interested in.

Questions to ask when choosing the best windows and doors

How can you navigate the window and door market effectively? We advise asking a few simple yet specific questions of your chosen installer. Each of these should demonstrate that you have done some research and are less likely to be told what a salesperson may want you to hear. With any of the answers you are given to these questions, you are welcome to contact us for more information and clarity. These questions apply to any window material, not just aluminium.

The good news is that any ‘claims’ made by a window company can be fact-checked relatively easily. In today’s digital age, abundant resources can help you validate these claims. This is precisely where platforms like the Aluminium Trade Supply Website come in. For over a decade, the Aluminium Trade Supply Website has been a trusted resource for consumers, offering clear, unbiased information on a range of aluminium products. Whether you’re curious about a particular brand’s origins, security features, energy efficiency, or design options, this platform provides accurate and up-to-date information to help you make an informed choice.

What is the window or door system?

Very few companies in the UK glazing industry have their own product or system that they have designed, extruded the aluminium, sourced the accessories, tested and brought to market from scratch. Therefore ask, “What is the window or door system”? An honest company will reveal this. Upon receipt of this information, you can then research the system company. System companies rarely make anything. They design and test the product, bring it to market, and sell it to a network of manufacturers. Some of these manufacturers make and fit their products. Others supply the product to installers nationwide.

Who manufactures your windows and doors?

Next, ask, “Who manufactures your windows and doors?” Most companies buy windows and doors from trade manufacturers. Researching the manufacturing company can give you valuable insights into their expertise, business tenure, and customer reviews.

Can you provide the test reports for security and weather protection?

With all the testing done by the system company or a specialist manufacturer, there should be no issue with an installer providing you with the required security and weather protection documentation. Windows and doors are tested by most providers, and you can often take this on trust, But if you do want to see the documentation, these are usually publicly available on the system company website or the manufacturing website.

Six top tips for choosing the best windows and doors for you

We hope the information given about the nature of windows and doors, their core materials and questions to ask your salesperson is useful and helpful if you are finding deciding which brand to choose a bit of a minefield. Here are our top tips to make the process easier for you.

sunflex heritage products at dusk on a contemporary house, regarded as some of the best windows and doors

There is no ‘bad’ window or door

With the significant materials in a window or door meeting certain standards and specifications, rest assured you are not buying a bad product by design. It is usually a badly made or badly fitted window or door that creates a poor customer experience and is rarely the product’s fault.

All claims made about windows and doors can be verified

In our experience, the most reputable window companies will give you honest advice and answers to questions. Remember, checking most of what you are being told is possible. Take the information, contact us, visit the system or manufacturing company websites and ask questions if something is unclear.

Be happy with the reputation of your chosen window or door provider

You will have seen advice everywhere about getting around three quotations and checking reviews and testimonials. This is indeed sound advice. We would also recommend checking your installer has experience with the products you wish to buy. A very good example is the latest generation of large and ultra-slim sliding doors. Sliding doors, steel-look glazing, and large windows with more glass are now popular in home design. The more complex the product, the larger and heavier it may be, the more experience your installer needs. So if you are about to buy a very large door or two-storey window, check if your chosen installer has experience in fitting these products, where a precise and professional installation is essential.

Consider a company offering several brands rather than just one or two

Expanding on the myriad options in the market, it’s also worth mentioning that not all window companies offer the same breadth of choice. Some companies may offer just one or two brands, while others have showrooms encompassing multiple windows, a complete range of sliding doors, and an array of bi-folding doors. These choices can come with varying styles, sightlines, and design elements. A company offering several brands demonstrates they are experts in more than just standard windows and doors.

Lean towards Approved installers and providers

It is usually a good sign if your chosen installer has an Approved Installer or Approved Dealer status. The manufacturing or system companies train and monitor their dealers, and some of the best windows and doors are only available via Approved Installers. Approved status is not just given to any window company. And you can always contact the manufacturing company to check that they are approved, although do bear in mind the system company or manufacturer and the installer are independent and unrelated businesses.

Try out the windows and doors

With the same material features, always try out the windows and especially the doors. How easily a bifold comes together and closes. How smoothly and effortlessly a large sliding door moves is often the best quality indicator. Just like other products, how something feels should reassure you.

Buying the best windows and doors – conclusion and summary

In conclusion, while the sheer number of choices can be overwhelming, remember that there are no inherently bad windows and doors on the market. Focus on the system, the manufacturer, the installer, the look and feel of the product, and its price. Considering these factors, you’ll be well-equipped to make the right choice. Remember, the “best” choice is relative, often depending on the unique requirements of your project and your individual preferences.

Since 2010 the Aluminium Trade Supply Website has helped homeowners and the trade find the right products from the proper suppliers. Contact us for more information and to discuss your project.

Providing expert help to homeowners and trade professionals since 2010




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16:42 30 Oct 23
Nick responded incredibly quickly to my enquiry (on a Saturday too!), and was able to offer invaluable advice on both aluminum systems and manufacturer / suppliers. Thanks Nick!
chris steerchris steer
16:18 09 Oct 23
Had a meeting with Nick during the grand designs show. Was extremely helpful and professional would highly recommend
Chris WesthorpChris Westhorp
19:55 13 Sep 23
Extremely helpful with pointing us in the right direction to find the products we required and suggesting firms that could reliably fit them.Nick was quick to reply and very detailed in his advice.Highly recommend reaching out to them.
Cathy GreenwoodCathy Greenwood
07:03 11 Sep 23
Update - A second email to nick for help on bifolds resulted in a detailed informative reply even on a Sunday ! This guy is so knowledgable and helpful .I approached Nick for an independent view on sliding doors v bifold and the different brand options . His reply was extremely detailed and prompt and allowed me to navigate this often confusing world in a much more informed way . Thanks so much Nick
Anthony CraigAnthony Craig
12:45 05 Sep 23
This is a must site for anyone looking for advice. Great service and very quick answers to questions. Nick has been of great help quiding us through the maze of aluminium products. Thank you
Philip DuffieldPhilip Duffield
20:24 26 Jul 23
I contacted Nick @ ATS for guidance on what aluminium sliding door systems would be suitable for an opening in an extension that is going to be both wide and tall. He came back really quickly with very detailed and incredibly helpful advice. He is clearly extremely knowledgeable about the systems on the market and their respective features and capabilities. If you’re feeling a bit lost by the overwhelming range of choices out there, I’d definitely recommend contacting him.
Dariush HekmatDariush Hekmat
17:25 19 Jul 23
Nick's advice is great. He is always quick to respond and spends time on responses, which really help to make an informed decision.
Alan FosterAlan Foster
07:51 12 Jul 23
Absolutely fantastic. Asked for advice about replacing Crittall (?) windows late last night and early this morning received 3 great suggestions and contact information for suppliers
Rachel LauRachel Lau
09:24 16 Jun 23
Fantastic website full of valuable and pragmatic advice about product selection and comparison: no other website gives information like this. Truly written for public interest. Don't hesistate to reach out to Nick via the mailing system. He responds very quickly, is friendly, and has very sound and high knowledgable advice. I have already shared this with my friend planning her own grand design.
guard Charlieguard Charlie
12:28 14 May 23
I emailed this company just on the off chance they could help me with new magnetic sliders for my patio door. They were not able to supply those but were so very helpful providing me with the name of a company who could. I am so very grateful at the great service. Dare say customers must be very happy. thank you so much.
Benjamin LewisBenjamin Lewis
10:06 04 May 23
Nick is very helpful indeed. Extremely knowledgeable on bifolds which was in relation to my query. Great website as well, some very useful articles. Particularly appreciated the article that lists all the major bifold options in order of their sightlines! Thank you!
P JonesP Jones
08:07 15 Apr 23
I asked Nick some questions about an installation we were considering and he replied within hours with some very useful suggestions that will probably lead us to using a different make and supplier. Thanks, Nick. Great work.
Nicholas WallNicholas Wall
13:18 02 Apr 23
Looking for fair and honest expert advice on all aspect of aluminium windows and doors? These guys will arm you with all the information you need to make the RIGHT choice in a highly complex, crowded marketplace. post a question and you will get a very quick professional answer you can rely on being based on fact. Thanks guys!
Giorgia SiriacoGiorgia Siriaco
16:25 21 Mar 23
After a lot of research to find doors that would meet our unusual size requirements and feeling increasingly uncertain about the best way to spend our small budget, I stumbled on the ATS website, and I'm so glad I did! I contacted ATS to request advice and Nick promptly replied with a wealth of information, providing us with options and relevant contact details. I only wish I'd found them sooner!
Carol NortonCarol Norton
10:01 17 Mar 23
I've been so confused about how to achieve the look I'm after, and going round in circles with various window/door companies, trying to get away from the huge chunks of plastic currently around my windows. I didn't expect an email to a company found through a Google search to really help - but I was desperate, so I tried. I'm SO glad I did. Finally I have clear explanations from ATS of where I've been going wrong, exactly what I'm looking for, and a list of local companies that might be able to provide it! The response has excelled my expectations and I feel as if I'm finally inching closer to a home with which I'll be happy and comfortable: thank you.
David NunnDavid Nunn
20:54 14 Mar 23
It is rare that I write reviews, however after my very positive communication with Nick - enquiring about suitable slim sash aluminium windows for my project, I felt that a review was definitely warranted. I can reinforce the many positive reviews posted so far, Nick was very quick to respond, providing comprehensive detail, with excellent independent advice.In summary, great service, thank you Nick.
Chantal AuerbachChantal Auerbach
13:04 09 Mar 23
Nick from Aluminium Trade Supply was incredibly helpful informative and pleasant to deal with. He responded quickly to emails and was very knowledgeable. Highly recommend being in touch with Nick if you are considering new aluminium windows or doors.
Lee JonesLee Jones
20:21 22 Feb 23
I dropped Nick at Aluminium Trade Supply an email re high security slim sightline bi-folds and their alternatives and he responded that quickly (and so comprehensively) that I felt bad I’d not paid him for his time!Nick Sir your product knowledge is outstanding and you are providing a level of service that goes wayyyy above and beyond expectations. I’ll definitely make sure I mention Aluminium Trade Supply to anyone I encounter looking for a fenestration solution 🙏🏼
15:13 13 Feb 23
We are looking to replace some old UPVC patios doors with aluminium ones. The ATS website is a great source of advice in an area where clear information is sorely lacking. Having used the website, I then followed this up with a number of specific questions relating to our search, and Nick came back very quickly with clear, detailed and very useful advice.I have been very impressed with both the website and with Nick's advice. My only regret is that I didn't come across ATS before replacing various windows in 2021 - I'm sure it would have saved me a lot of grief and money! Thanks again Nick.
Azza McCabeAzza McCabe
17:47 01 Feb 23
So impressed with this company.Responded to my query quickly andgave valuable advice. Nick was extremely helpful and we were able to move forward with our project.
Adri LoloçiAdri Loloçi
11:21 08 Jan 23
Nick was super fast to respond and provided some great recommendations. I would recommend this website to anyone looking to find bifold or sliding aluminium doors.
Stephen HoustonStephen Houston
16:16 03 Jan 23
Looking for aluminium crittall style internal door and external patio French doors. Noted good reviews and thought would ask for advice. Comprehensive reply with excellent independent advice and lists of fitters who could provide products and installation. Great service.
Inga GeachInga Geach
08:25 21 Dec 22
Nick from Aluminium Trade Supply has been extremely helpful with navigating the jungle that is aluminium glazing for our upcoming extension project. His advice was prompt, detailed and always impartial. Very grateful for your input, thanks Nick!
Amanda BurtonAmanda Burton
10:54 16 Dec 22
Brilliant website and an excellent service. Nick provided not only detailed advice and supplier contacts, but highlighted the considerations of various products so I could make an informed choice. Our Sunvista minimal sliders were fitted this week and I couldn't be happier, stunning. Thanks once again for your advice and recommendations, invaluable!
Keith BarnesKeith Barnes
17:18 10 Dec 22
Very helpful advice given to my question, including the name of 3 different companies that i could try for the product being enquired about. Many thanks
Munim ChowdhuryMunim Chowdhury
11:45 13 Sep 22
Nick has been very helpful on signposting me to a number of partner organisations for steel/aluminium doors.
SUSAN wallaceSUSAN wallace
17:26 31 Aug 22
My experience with this firm was exceptionally good and this is notalways the case as a female, dipping a toe into technical waters.I was spoken too with courtesy and at a level that helped me consolidate what was needed .On top of that I was given a list of companies and places where I could obtain the type of product I needed.I could not thank them enough and would certainly go there again and reccommend others do too.
Paul SalterPaul Salter
22:39 22 Aug 22
Contacting Aluminium Trade Supply is like contacting the Oracle direct. Advice is always comprehensive and balanced. On multiple occasions they have provided me with options that fully meet our objectives. Many thanks.
Nick McCormackNick McCormack
20:25 14 Aug 22
Really helpful and useful came back to me on a Sunday with some invaluable information. Highly recommended.
ray addisonray addison
13:14 14 Aug 22
received a prompt reply to my query,and helpful information from ATS