When choosing how and where to buy aluminium windows, the retail supply and installation route still provides an easier process, better guarantees, and less for you to organise.

However, there are other ways to buy aluminium windows, save money, complete your property renovation faster, and, for those who love to project manage, have more control. We’ve created a helpful buying guide covering most of what you’ll need to consider when you buying aluminium windows.

Replacing windows vs buying for a new build or extension

When replacing existing windows, how and where to buy aluminium windows can differ from windows for a new build or extension. 

Replacing windows where no builder is involved is the most straightforward route. Often, the project involves a like-for-like replacement of the existing windows, which is usually a simple window installation. Slightly more ambitious could be deciding to change the look of your home with a new window design and colour. 

Choosing windows for a new extension or new home is a more complex task. It’s not just about creating the window openings, there are other factors to consider. 

• Ensure your selection suits your home and lifestyle in the long term.
• Arriving at the right window design or specification.
• Compliance with Building Regulations for energy efficiency, ventilation, and safety.
• Working with an architect, builder and carrying out research.
• Timing your windows purchase and installation with the build and other trades.

In addition, going down the supplier and installer route addresses potential installation issues and building regulations. For example, perhaps the new windows are above a conservatory or glazed roof – the installer can’t stand on the roof as most windows are fitted from the outside. You may need scaffolding to access hard-to-reach windows. What size of window cill or internal window board is best? You’ll need to consider first-floor windows as a means of escape or an easy cleaning facility. What about child restrictors? Do you need trickle vents? All of these considerations and many more are familiar to your window installer.

Moreover, the retail route works best when you buy aluminium windows for a new extension together with patio doors with a low threshold; otherwise, your door provider, builder and/or architect would need to work collaboratively to give you the desired flush look. Similarly, you may need to work out the positioning, opening modules, and how any shaped windows will work, such as an apex window above a bifolding door.

Where to buy your new aluminium windows

For most homeowners, the full supply and installation route remains the simplest and lowest-risk way to buy aluminium windows. The installer will have a showroom, they take the responsibility for the survey, manufacturing sizes, installation and aftercare.

They are best-placed to explain each product in detail and which one will be best for your project. This is also the best route to ensuring you get the full warranty possible as well as FENSA or CERTASS certification.

Here’s the buying routes comparison table:

Route	Best For	Pros	Cons
Retail supply and install	Most homeowners replacing windows or buying for an extension	Full survey, longer guarantees, aftercare, single point of responsibility	Usually the most expensive route
Builder supplies and fits	New builds and extensions where you trust your builder	Potentially lower pricing, faster lead times, one contractor relationship	Limited product choice, shorter guarantees, measurement errors more likely
You buy, Builder fits	Homeowners who want to choose their own products	You control the specification and brand	No product warranty, you carry the risk on survey, sizes and mistakes
Direct from manufacturer	Confident buyers who’ve done their research	Can save money, good showrooms, some offer survey and assisted fit	Responsibility still sits with you, limited warranty or aftercare
Online	Simple, standard replacements only	Potentially lowest price	Highest risk. Product may not match images, no survey, all responsibility on you, missing essential parts.

You buy the windows and your builder fits

With many online websites, homeowners can buy aluminium windows directly from some suppliers and their builder installs them as above. This provides the pros of the builder supplying with the additional benefit that you get to research the style and manufacturer you want rather than what the builder chooses via a preferred supplier. However here the cons, get greater:

• You’ll need to find a window supplier who will sell direct to the public
• Some manufacturers only sell to trained installers
• The same limited warranty applies
• You will be expected to supply the correct order details, sizes and specifications
• You will need to manage and resolve any product delays or mistakes
• If your manufacturer supplies unglazed products, you/your builder will need to order the correct glass.

The hardest part of this route is establishing manufacturing sizes. Manufacturers supplying direct rarely offer a surveying service. And if openings are irregular across the width and height. Does your builder have the expertise to do the window survey and allow the necessary tolerances? Any measurement mistakes will be very costly for you.

Buying Windows Direct from the Manufacturer

Whilst all of this sounds daunting, good direct-to-public suppliers of doors and windows have worked hard to make it easy. Some will provide a survey service for an extra cost, and many will provide information for builders about how to measure and install the doors and windows. A few even offer an ‘assisted-fit’ service for more complicated glazing. For further advice, we’ve created a full explanation of potential pitfalls with buying direct versus getting someone else to fit.

In most cases you can buy fully fabricated windows and doors directly from the manufacturer. Many manufacturers have excellent showrooms where you can view the products and discuss your project. Some even offer a chargeable survey to take the measurements or an assisted fit service, again chargeable. Whilst this route still places responsibility on you, if you’re confident managing this process, you can save money.

Buying aluminium windows online

There are the usual precautions to buying anything online, but with windows, it can get more complicated. First of all, it’s worth establishing whether the online supplier is a manufacturer of these or buying in via the trade route and then selling online.

The biggest risk to buying online is getting the right product and that the windows advertised are those you’ll get. For instance, are the images representative of the product? Windows aesthetics are frequently governed by sizes. You may see a slimline aluminium window image online , but what you get is thicker in profile because it’s larger than the sizes possible with slimline profiles. Unless your online supplier provides absolute clarity on the dimensions you’ll get, this is by far the riskiest route, even if the cheapest.

Overall, online places a larger responsibility on you. Of course, all the considerations with the builder or trade route above still apply to buying online.

Not All Aluminium Windows Are The Same

There has never been more choice when buying aluminium windows. However, one of the biggest misconceptions is that all aluminium windows are broadly the same. They are not.

Different systems are designed for different applications. Some are intended primarily for replacement windows in existing homes. Others are designed for contemporary new builds, large glazed openings or commercial projects. Understanding the differences can help you avoid expensive mistakes.

There are many aluminium systems companies and major brands of aluminium windows. Some of these are predominantly focused on the residential market and windows for dwellings. Other brands are used more in commercial buildings or developments of newbuild flats and houses. That does not make one better or worse than the other. Architects, developers, builders and homeowners often prioritise different aspects of a window. Whilst a homeowner may focus on appearance and sightlines, a developer may be more concerned with specification compliance, lead times and budget.

Then there are the different manufacturers of windows and doors. With just over 11000 window installers in the UK (source: Insight Data Market report) there are only around 900 companies making windows. Therefore, who manufactures your windows can be just as important as who installs them. A good installer working with a reputable manufacturing partner can often deliver a better result than a well-known brand installed poorly.

Our advice is to ask an installer not making your windows:

• Who is your manufacturing partner?
• What system am I purchasing?
• Are my windows made in the UK or sourced from factories abroad

There are several companies that rebrand or white-label existing window systems, making it difficult for homeowners to know exactly what product they are buying. If you are unsure what brand is being sold to you or you can’t locate it on this website, do get in touch and we can clarify the system for you.

The expertise of your installer is also important. For example, only specialist installers will carry out architectural glazing, structural glazing and the installation of high end sliding doors. They should also be able to demonstrate expertise in having a track record. Some installers focus only on replacement window and new build work. Others can offer the full range of services, and at the upper end of the market are those providing high-end sliding doors that require expert knowledge as well as all the required calculations any complex project demands.

Don’t Buy Aluminium Windows on Sightlines Alone

Where you live can affect your choice of windows and you should never buy on sightlines alone. This is especially important on large picture windows, gable windows, facade and stairwell screens and other complex window designs. Calculations need to be carried out to ensure the frame sizes and tolerances, inertia values and overall design is suitable for the product.

This is not as important in a suburban house that is sheltered from all sides, but is important if you live in the countryside, high ground, coastal areas and anywhere subject to driving wind, rain or other conditions.

Other reasons not to buy on sightlines alone include compliance with Building Regulations, security performance, maintenance requirements and long-term ownership considerations. Some window only meet U-Values triple glazed, some European systems are not designed for trickle ventilation are just two examples. You also need to consider the security testing carried out and any anticipated maintenance the product may need.

Most windows with minimal sightlines may have a bonded or structural glass design. Therefore consider how easy it will be to replace the glass should it get damaged, especially if your installer is no longer in business.

We can help advise you on all aspects of slimline windows and advise where the slimmest frame isn’t always the best window for your project.

Building Regulations Matter More Than Ever

Whether you are replacing windows and doors or building new, Building Regulations Applicable to windows and doors, must be followed.

Your installer and their manufacturer should be experienced in meeting these whether for insulation, ventilation, fire safety, glass safety and even overheating as we use glass more and more in our homes.

Depending on your project, Building Regulations may cover thermal performance, ventilation, security, fire safety, safety glazing and overheating. Whilst you don’t do not need to become experts in these requirements, your chosen installer and manufacturer should be able to demonstrate how their products comply. For most replacement windows, your installer’s FENSA or CERTASS registration usually covers compliance as well.

Window guarantees when you buy aluminium windows

When you buy aluminium windows, the best guarantee is the one you get from the retail, supply and installation route.

Many window installers provide long product and fitting guarantees that actually exceed what they get from their suppliers. An excellent example is glass. It’s impossible to find a glass unit bought from a glass manufacturer with a guarantee longer than five years. Some installers pass on this same time period to you. Others choose to take a risk by offering you a ten year guarantee.

Similarly, there are products available from specialist manufacturers who honour their products for up to 25 years, but only when bought through an approved and trained dealer. You’ll miss out on this extended warranty and peace of mind guarantee when buying anywhere other than through the retail route.

Whether you buy windows and your builder installs, or leave the windows sourcing to your builder. Check the warranty you’ll get both with the product and the installation. Wherever you buy aluminium windows, the warranty and guarantee you’ll get won’t be the same.

Always ask for the warranty in writing and clarify whether it covers the product, installation, glass units and hardware separately.

When Should You Order Aluminium Windows?

When you order your aluminium windows is also something you need to think about and work with your chosen installer. Whilst most windows and doors are available in many ‘standard’ colours today, such as various shades of greys, blacks, whites and heritage colours, you need to consider:

• The installation schedule of your chosen installer which could be weeks or months ahead if they’re busy
• Manufacturers making residential and commercial windows tend to get very busy in the summer with schools shut and being refurbished
• Whether your windows are being made abroad
• A non-standard colour on extended lead times.

Some manufacturers have greater capacity than others, with very fast lead times, others need to take longer. Here are some additional things to consider:

• Ordering too early and your windows could get damaged on a building site by other trades
• Ordering too late and you will have new build openings that remain boarded up
• Lead times on different products vary. Windows, bifold doors, and sliding doors all take different times to make.

Once your windows enter production, changes can be expensive or impossible. Taking ten minutes to check the paperwork thoroughly before manufacture can save significant time, money and frustration later.

Ongoing maintenance and after-care

No window or door is a fit-and-forget product. Modern aluminium and PVCu materials are widely marketed as low-maintenance, giving the impression that your new windows, once installed, never need anything but a routine clean. This is not true.

Over time, all windows will require routine maintenance and adjustment. Many retail suppliers and installers offer such a service either free, as part of a service package, or at a one-off cost. 

Questions To Ask Before Buying Aluminium Windows

People contacting this website are often unsure what their quotations mean or what questions to ask their window company. You can always get in touch for help and advise. But the following questions, any reputable installer must be happy to answer.

• Can I see previous installations?
• Who manufactures the windows?
• What system is being used?
• What guarantee is included?
• Who measures, your surveyor or an external contractor?
• Who installs, your installer or external subcontractors/self employed fitters?
• What happens if measurements are wrong or there is a problem with my windows?
• Are replacement parts available?
• What aftercare is available?

Need Help Choosing Aluminium Windows?

With so many products on the market it is easy to get confused by marketing messages, the sheer choice and what some of the technical information means for your project. The Door and Window Experts Website provides independent and impartial advice to homeowners planning replacement windows, extensions, renovations and new build projects. We can help with:

• Help choosing products
• Help choosing installers
• Help comparing brands

Or if you have specific requirements, please do get in touch. Our service is free.