Sheerline Classic
Aluminium Heritage Windows
Original steel windows look wonderful and behave badly. This is the aluminium answer to them: the same slim dark grid and the same stepped sash face, with a thermal break through the frame, modern glass and nothing left to rub down and repaint.
Key specifications
Aluminium Heritage Windows
- U-value 1.4 W/m²K
- Colour choice Any RAL colour
- Sightlines 60.5mm
- Energy rating A rated
What it replaces
The steel window, without the cold.
Britain put steel windows into a great many houses between the wars, Crittall being the name most people remember, and they are still the reason those houses look the way they do. They are also single glazed, they rust from inside the frame outwards, and by now most of them bind in the wet and run with condensation from October to March.
Sheerline Classic is aluminium drawn to the same proportions and given a thermal break, modern glass and a powder coat that does not need painting. It has quietly become the window the trade reaches for when somebody wants steel back, and we fit it with the stepped sash, which is the profile that keeps the shoulder and the shadow line the original had. Get that wrong and you have a nice window that reads as new.
- 60.5mm on a casement, and from 36.5mm on a fixed pane
- 1.4 W/m²K double glazed
- Twelve powder-coated colours, or any RAL you can name
The look
A stepped sash, and the bars in the right places.
Two things decide whether a window reads as steel. The sash has to step, so the face throws the shoulder and the shadow line an original had, and the bars have to be laid out the way the house would have had them. Everything else is colour and glass, and you can settle that later.
No bars
The frame and the mullions do all the work. Right where the openings are already small, or where the original had no bars in it.
Georgian grid
Bars both ways, squaring the glass up. The layout most people picture when they picture a steel window.
Horizontal
Bars across only, wider apart. The 1920s and 1930s pattern, and the one that suits a bay or a long low opening.
You can build the window itself on our designer, bars and colour and sizes together, and it prices as you go. It is the same software and the same price list we use at a consultation, so the figure is the real one.
The system
What you get that the original never had.
Sheerline Classic is one system, and we sell the whole of it: these windows and the heritage doors that go with them. What follows is the part of it a steel window cannot answer back to.
- A thermal break through the frame
- Sheerline run their Thermlock multi-chamber break through the Classic frame instead of the polyamide strip most aluminium systems use. Double glazed the window reaches 1.4 W/m²K, where an original steel window has nothing at all between the outside air and your curtains.
- Slim, and slimmest where it shows
- 60.5mm sightlines on a beaded casement, and fixed panes from 36.5mm. On a small stone opening, that is the difference between a window and a frame with some glass in it.
- Tested to PAS 24, and beyond it if you want
- Sheerline hold PAS 24:2016 on the Classic window, and Secured by Design, the police standard, with a laminated glass upgrade. Both are theirs rather than ours, and the second is something you choose rather than something every window arrives with.
- Corners cleated, not welded
- The mitres are cleated, which keeps the frame square. Corners that move are the usual reason a slim window starts to catch after a few winters, and they are the first thing to go on the steel window this replaces.
Figures and accreditations are Sheerline's published specification for the Classic system. What suits your opening, and what it costs, depends on the opening.
Our work
Three windows, three stone openings.
White Classic frames in an ironstone gable, one window into each original opening so the stone mullions still carry the elevation rather than being hidden behind a single wide frame. On a building like this the stone is the architecture and the window is a guest in it.
It is also the argument for aluminium on an old house in one picture. A frame this slim leaves the openings looking the size they were built, which is the thing you notice from the road without being able to say why.
The set
The doors match, down to the bar spacing.
The Classic heritage door is drawn on the same system as these windows, which is why the two sit together properly rather than nearly matching. The stepped face runs on at the same depth, the bars line through at the same spacing, and both come in the same twelve colours, so a garden door between two windows reads as one piece of work.
It is worth deciding both at once even if the door comes later. We can hold the colour and the bar layout on file, and the survey takes the door opening at the same visit.
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 Heritage Windows
Are heritage windows the same as steel windows?
No, and that is the point. They are thermally broken aluminium shaped to look like steel, so you get the slim gridded appearance of an original Crittall style window without the cold frame, the rust or the repainting.
Can you replace original steel windows with these?
Yes, and it is what the system was drawn for. Old steel frames are usually set straight into the masonry, so we survey the opening first and tell you what making good will involve before you order anything.
What bar layouts can I have?
A Georgian grid, or the horizontal layout that suits a 1920s and 1930s house. Bars can go on every pane or only the ones that need them, and you can put the layout together with the sizes and the colour on our online designer, which prices it as you go.
Will they be warmer than what I have now?
If you are replacing single glazed steel, considerably. Sheerline publish 1.4 W/m²K for the Classic window double glazed, and the thermal break through the frame is what stops the condensation an old steel window collects, which is the thing people actually notice on a February morning.
Do they match your heritage doors?
Exactly, because they are the same Sheerline Classic system. The stepped face, the bar spacing and the twelve powder-coated colours are shared, so windows and doors specified together look like one job.
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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Where we fit
Aluminium heritage 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.