Fenster Glazing
Aluminium Casement Windows
Aluminium windows are chosen for slim sightlines, strength and a clean architectural finish. We specify Sheerline aluminium systems around frame style, colour, glazing, security and installation detail so the finished windows suit the building and the view.
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Key specifications
Aluminium Casement Windows
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U-value
1.0 W/m²K*
* Lowest achievable.
- Colour choice Any RAL colour
- Energy rating A+ rated
- Outer frame 72mm
Product information
Aluminium Casement Windows
Aluminium windows are chosen for slim sightlines, strength and a clean architectural finish. We specify Sheerline aluminium systems around frame style, colour, glazing, security and installation detail so the finished windows suit the building and the view.
Slim modern frames
Aluminium strength allows narrower-looking frames and larger glass areas, helping bring more daylight into the room.
Thermlock technology
Sheerline aluminium systems use Thermlock multi-chamber thermal technology to improve insulation compared with older aluminium approaches.
Flexible window styles
Casement, French, tilt and turn and fixed aluminium windows can be combined to suit contemporary extensions and whole-home upgrades.
Powder-coated colour
Aluminium frames can be specified in a wide range of RAL colours, including dual-colour options where suitable.
Security-focused details
Robust aluminium construction, locking hardware and suitable glazing options help each opening feel secure as well as slim.
Slim modern frames
Aluminium strength allows narrower-looking frames and larger glass areas, helping bring more daylight into the room.
Thermlock technology
Sheerline aluminium systems use Thermlock multi-chamber thermal technology to improve insulation compared with older aluminium approaches.
Flexible window styles
Casement, French, tilt and turn and fixed aluminium windows can be combined to suit contemporary extensions and whole-home upgrades.
Powder-coated colour
Aluminium frames can be specified in a wide range of RAL colours, including dual-colour options where suitable.
Security-focused details
Robust aluminium construction, locking hardware and suitable glazing options help each opening feel secure as well as slim.
Product guide
More information on Aluminium Casement Windows
Aluminium windows give slim sightlines with important engineering behind them: thermally broken frames, bead options, security upgrades, concealed drainage and broad colour choice.
Sheerline Prestige
SBD option
System
Sheerline Prestige aluminium window system
Prestige is the main aluminium window system for slim frames, strong sections and a modern powder-coated finish.
Sightlines
Slim frame options with exact sightlines confirmed by opening style
Opening style affects how slim the finished window looks, so fixed panes, casements and dummy sashes are planned together.
Thermal design
Sheerline Thermlock multi-chamber thermal break technology
Thermlock technology separates the inside and outside aluminium to reduce heat transfer through the frame.
Security
PAS 24 and Secured by Design options available with suitable glass and hardware
The security specification depends on glass, locks and hardware as a complete window specification, not one isolated part.
Specification choices
Finish the design with your colours, glass and hardware.
Choose your colours, privacy glass and hardware; each guide helps narrow the detail before survey.
Colour
Twelve standard colours, powder coated in the UK.
Powder coating is baked onto the aluminium rather than painted over it, so it does not flake and it never needs redoing. Anthracite Grey and Jet Black are the two we fit most often, and both sit well against brick and render alike.
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Pure White
RAL 9010 Matt
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Hipca Gloss White
RAL 9910 Gloss
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Anthracite Grey
RAL 7016 Matt
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Jet Black
RAL 9005 Matt
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Cream
RAL 9001 Matt
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Agate Grey
RAL 7038 Matt
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Squirrel Grey
RAL 7000 Matt
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Pastel Turquoise
RAL 6034 Matt
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Chocolate Brown
RAL 8017 Matt
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Silver Metallic
Metallic effect
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Mid Bronze Metallic
Metallic effect
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Black Metallic
Metallic effect
You can have a different colour inside and out, and beyond these we can match any RAL colour, confirmed against a sample before your window is ordered. If you have a shade in mind, ask and we will tell you what is possible. Compare colours across every material
Handles
Six handle finishes, lockable as standard.
The S2 Signature range, in left and right hand versions so the operation matches the way the window opens. The release button and the screw cover cap match the finish you choose.
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White
White Powder Coat
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Black
Black Powder Coat
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Chrome
Chrome Plate
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Gold
Gold Electroplate
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Satin Silver
Satin Silver Electroplate
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Monkey Tail
Traditional Monkey Tail Handle
Handing, restrictors and key-locking are settled at survey, alongside how far the sash swings and whether the handle can be reached comfortably. See the full handle specification
Product questions
FAQs about Aluminium Casement Windows
Why choose aluminium windows?
Aluminium is strong, slim and durable, making it a good choice where clean sightlines and larger glass areas are important.
Are aluminium windows energy efficient?
Yes. Modern thermally broken aluminium systems improve comfort significantly compared with old aluminium frames.
Can aluminium windows be coloured?
Yes. Aluminium can be powder coated in many RAL colours, with dual-colour options available on some systems.
Do aluminium windows suit traditional homes?
They can, especially where slim frames or heritage styling is wanted. We will compare standard, flush and heritage options.
Will the sightlines be checked before ordering?
Yes. We review frame sizes, mullions, opening positions and glass areas during specification and survey.
Order process
A clear process from first quote to aftercare.
Four steps. The first one has two ways in: price it yourself online, or have us come out. After that it runs the same either way.
Your price
Price it yourself on the online tool, or book a free consultation and we build the same quote with you. Both run on the same price list, so the figure matches.
Technical survey
Once you go ahead we survey before anything is made. Not a second sales visit: the measurements, thresholds and fixings the factory needs to build it right.
Installation
Fitted by our own installers rather than subcontractors, trained on the systems we sell and working carefully in a house someone lives in. We clear up after ourselves before we leave.
Aftercare
A ten year insurance-backed guarantee through the CPA on new windows and doors, and your FENSA certificate sent direct. Anything afterwards, you ring us, not a call centre.
What Milton Keynes homeowners say
Real reviews from real installations. Every one is public, so you can go and check them yourself.
Stuart Matthew
7 months ago
Fenster have just completed a front door installation on my new property - fantastic job and strongly recommend! The online design tool is great, Perry back at HQ is brilliant as is his communication. Andy, who installed the door, is a top gent and professional. Will definitely be a returning customer.
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Joanna Hayes
3 months ago
Really happy with the service we received from Fensters Windows. Aaron and Shane turned up on time and were both really friendly. They explained any issues as they went along and talked us through the different options, which we really appreciated. They did a great job fitting our new back doors and cleaned up everything afterwards. We also paid exactly what we had originally been quoted, with no unexpected extra costs. Really pleased with our new doors and would definitely recommend Fensters Windows. Thank you Aaron and Shane!
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Digger
3 months ago
We have used Fensters for years on a variety of glazing work, and 2 door installations. They are competitively priced and responsive. They take great care over measuring and specifying the work, giving you a clear quote so you understand what you are getting (thanks Perry!). The fitters are all extremely competent and personable. We had to replace our front door for accessibility reasons, they gave us confidence that our requirements would be met, reproduced the intricate leaded and stained-glass pattern of our old door, and did a quality fitting job (thanks to Johnnie and Shane!). In summary they are our go-to suppliers for all replacement and repair work.
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Silvia Peraro
2 months ago
I had an excellent experience with Fenster Glazing from start to finish. Nick Perry and David managed the initial quote to installation process seamlessly, keeping communication clear, honest, and completely stress-free. When it came to the actual fitting, Zac and Shane did a fantastic job with the installation, working efficiently and leaving everything spotless. The professionalism from the entire team was top-notch, and the final result looks brilliant. I highly recommend them.
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Bernie Raffe
4 months ago
Great service from Fenster Glazing, very happy with our new bi-fold door, glass door and windows (with built-in blinds) There was an issue with the wrong spec of glass provided to them from their supplier, so they had to temporarily board up a door and a window, but this was put right within a few weeks. Recommended, thanks.
Read on Google Zak Jessup 12 Jun 2025Cannot recommend higher! Nick and Perry were really helpful in getting my windows sorted ASAP.
Read on Google Norman Cummings 10 Jun 2025The best service ever, great workmen, very high standard and in the finish, excellent eye to detail.
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Related products and service areas
Double Glazed Windows Milton Keynes
uPVC Casement Windows
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Sliding Sash Windows
uPVC Tilt & Turn Windows
Bow and Bay Windows
Aluminium Flush Windows
Aluminium Heritage Windows
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Where we fit
Aluminium casement windows in Milton Keynes and the towns around it.
Each town has its own page: the homes there, what to check before you order, and who to ask about permission.