Fenster Glazing
uPVC Casement Windows
Casement windows are the practical all-rounder for warmer, brighter homes. We specify Liniar uPVC profiles, opening layouts, colour, handles and glazing around each room so the finished windows feel simple to use and properly suited to the property.
Key specifications
uPVC Casement Windows
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U-value
0.95 W/m²K*
* Lowest achievable.
- Colour choice 16 options
- Energy rating A+ rated
- Security PAS 24
It’s not just a uPVC window. It’s a made-to-measure, draught-sealed, A+ rated, multi-point-locked, ten-year-guaranteed uPVC window.
A casement hinges at the side or the top and opens outwards. Openers and fixed panes are made into one frame, so a single window can do more than one job.
It’s the 70mm Liniar EnergyPlus casement. We fit it as standard.
Energy efficiency
A standard uPVC profile has four chambers. This one has six.
Liniar call that profile EnergyPlus, and it is the one we specify on every casement we fit.
- 0.95W/m²K
- Whole window, with the 36mm triple glazed unit
- A+rated
- On the specification we list
- Sixchambers
- Through every frame section, against four as standard
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Six sealed air pockets, and each one interrupts the route heat takes out of the room. They sit inside the frame where you never see them, so nothing about the window looks different for it.
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The weather seal is formed with the profile as it is extruded rather than pushed into a groove afterwards, so it cannot shrink back or work loose at a corner. Corners are where a pushed-in gasket fails first.
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Panes, coatings, argon fill and a warm edge spacer decide most of the whole window figure. A 28mm double or a 36mm triple, with the triple reaching 0.95 W/m²K. The number we agree follows your glass rather than a brochure.
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Fixing, sealing and finishing are what connect a tested window to your actual wall. Our own installers do it, which is why the ten year guarantee on the work is ours to give.
Liniar profiles are lead-free and recyclable at the end of their life, designed, extruded and tested in Derbyshire. The frame carries a ten year Liniar guarantee; our installation carries ten years of ours.
Security
Multi-point locking is not an upgrade. It is what we fit.
It is a Kenrick Excalibur. What you can add on top of it is laminated glass, and a window tested to PAS 24 or Secured by Design.
Kenrick Excalibur multi-point mechanism
- One turn, the whole edge
- The Kenrick Excalibur strip runs the length of the sash, and one turn of the handle throws steel shoot bolts into the frame and bi-directional claws into keeps down the sash edge, so the window is held into its seals along its whole length rather than at the handle.
- Tested, and guaranteed ten years
- Kenrick test the mechanism to 100,000 opening cycles and 240 hours of salt spray, beyond what BS EN 1670 asks, and guarantee it for ten years.
- PAS 24 and Secured by Design
- Both available. Part Q asks for PAS 24 on new dwellings and some extensions, so tell us at survey if yours is covered and we will specify a complete window tested to it.
- Laminated glass, an optional upgrade
- A laminated pane has a bonded interlayer, so it holds together instead of breaking through. That is the difference between a broken window and an open one, and it is the upgrade we would point at first on a ground floor or any window out of sight from the road.
Versatility
One system. Every opening in the house.
Three ways of opening and any combination of them, in one outer frame, at any size we can make.
Side. Top. Fixed.
Side hung
Hinged on the stile and held at any angle by a stainless friction stay. Where a bedroom needs its escape route, egress hinges swing the sash to ninety degrees so the clear opening meets the Building Regulations minimum of 0.33m², at least 450mm each way.
Top hung
Hinged in the head with the handle on the bottom rail. The open sash sheds rain clear of the opening, which is why top-hung sashes sit above fixed panes and over kitchen worktops. A restrictor holds the first opening to around 100mm where children sleep.
Fixed pane
No hinges, no gearing, no handle. The glass is bedded straight into the frame, so a fixed pane costs less than an opener the same size and carries a slimmer border and more glass. Ventilation and escape come from the openers around it.
And any combination of the three.
This is where the range stops being a list: a fixed centre with openers either side, a run of top openers over a worktop, a three pane window, a splayed bay, a bow, a dormer. Transom and mullion positions are drawn for your opening rather than picked from a catalogue.
One frame, any arrangement. Now the glass, and the finish.
Design your windowGlass spec
Toughened glass comes as standard. The rest are upgrades.
All five share the same core: a low-E coating, argon in the cavity and a warm edge spacer. What changes is how many panes there are, and how the glass behaves if something hits it or the road outside is loud.
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Eco Toughened 1.2 W/m²K What it does
Our standard. If it is ever broken it goes to blunt granules rather than shards.
- Safety
28mm unit, toughened both panes.
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Eco Laminated 1.2 W/m²K What it does
Stays in the frame if it is broken, so it is far harder to get through.
- Safety
- Security
28mm unit, one pane bonded to a clear interlayer.
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Eco Acoustic Laminated 1.2 W/m²K What it does
Takes the edge off a busy road or a flight path.
- Safety
- Security
- Quiet
6.8mm Pilkington Optiphon, 18mm cavity, 4mm outer pane.
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Triple Glazed Eco Toughened 0.95 W/m²K What it does
The warmest rooms on the list.
- Safety
- Warmth
36mm unit, three panes and two cavities.
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Triple Glazed Eco Acoustic Laminated 0.95 W/m²K What it does
Quietest and warmest together.
- Safety
- Security
- Quiet
- Warmth
36mm unit with the Optiphon laminate in one pane.
U-values are whole window figures. The survey confirms the glass before anything is ordered.
Detail
Bars, horns and lead.
These are what make a new window look like it has always been there. All four are quoted with the window rather than added on afterwards.
Colour
Sixteen colours outside, matched or white inside.
A uPVC colour is a foil bonded to the profile at the factory rather than paint applied afterwards, which is why the woodgrains have a grain you can feel and why none of them need repainting.
- Smooth White No foil, RAL 9003
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White
Foil, RAL 9010
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Cream
Foil, RAL 9001
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Chartwell Green
Foil
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Irish Oak
Foil
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Golden Oak
Foil, RAL 8001
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Rosewood
Foil
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Anthracite Grey
Foil, RAL 7016
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Black Brown
Foil, RAL 8022
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Agate Grey
Foil, RAL 7038
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Silver Grey
Foil, RAL 7001
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Basalt Grey
Foil, RAL 7012
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Slate Grey
Foil, RAL 7015
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Gale Grey Finesse (Anthracite Smooth)
Foil, RAL 7016
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Blue
Foil, RAL 5011
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Dark Green
Foil, RAL 6009
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Dark Red
Foil, RAL 3011
Availability, lead time and cost vary by colour, so we confirm all three before you order rather than after. 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
Privacy glass
Privacy where the room needs it.
Bathrooms, en suites, ground floor side windows and anything overlooked. Obscured glass goes in the same frame and the same sealed unit, so it changes nothing about how the window performs.
Our work
Casements, fitted by us.
Every photograph here is one of our installations, taken on the day we finished. Click any of them for a closer look. Every photograph is one of our installations. Tap any for a closer look.
Two faces
Standard or flush.
The same 70mm Liniar uPVC, the same sixteen colours, the same fitters. The sash is the difference, and it changes both the look and the glass.
| Specification | Standard | Flush |
|---|---|---|
| The sash | Stands proud of the frame | Closes level with the frame |
| Fixed panes | Glazed into the frame, so more glass | Matched dummy sash, so equal lines |
| Glazing | 28mm double or 36mm triple | 28mm double |
| Whole window U-value | 0.95 W/m²K | 1.2 W/m²K |
| Energy rating | A+ | A+ |
| Suits | Most homes, and the wider specification | Period and cottage elevations |
Casement window questions
Plain answers, starting with the basics.
All of these refer to the 70mm Liniar EnergyPlus system on this page.
What is a casement window?
A window with sashes hinged at the side or the top, opening outwards. Opening sashes and fixed panes are made into one frame, so a single window can do more than one job.
What is the difference between casement and flush casement windows?
The sash. On a standard casement it stands slightly proud of the frame, and fixed panes are glazed straight into the frame so they hold more glass. On a flush casement the sash closes level with the frame for a traditional joinery look, with fixed panes matched to the openers so every pane reads the same. Standard takes 28mm double or 36mm triple glazing and reaches 0.95 W/m²K; flush takes 28mm double and reaches 1.2 W/m²K. Both are A+ rated.
Which Liniar system do you fit?
The 70mm Liniar EnergyPlus system in the sculptured profile, a six-chamber uPVC platform used for both replacement and new-build work. Glass and hardware are confirmed for your individual job.
Why do you fit Liniar?
The 70mm EnergyPlus frame carries six chambers, sculptured rather than chamfered, and welded at the corners rather than screwed. Triple glazed it reaches 0.95 W/m²K, and the profile is lead-free. Liniar guarantee the frame for ten years and we guarantee the installation for ten, which are two different things and both worth having.
What U-value can an EnergyPlus casement reach?
0.95 W/m²K, with the 36mm triple glazed unit, which makes it an A+ window. Size, layout and glass all move the complete-window figure, so the number we agree follows your final specification rather than a brochure.
Are casement windows secure?
Multi-point locking is what we fit as standard, not an upgrade, and PAS 24 or Secured by Design can be specified on top. Part Q asks for PAS 24 on new dwellings and some extensions, so tell us at survey if yours is covered and we will specify a complete window tested to it.
Can I have triple glazing?
Yes. The 70mm frame takes a 28mm double glazed unit or a 36mm triple. Whether triple is worth it depends on the sash size, the weight and what you are actually trying to improve, so we will compare it with you rather than treating it as an automatic upgrade.
Will new casements make the house quieter?
They can, when the whole specification is designed for it. Liniar publish around 33 decibels for a standard double glazed unit and up to 37 decibels, rated 37 (-2;-5), where the window is built for acoustics. Reaching the higher figure is the glass doing the work rather than the frame. Pane thicknesses, frame seals and the ventilation path all affect the result, and the ventilation path is the one people forget.
How many colours are there?
Sixteen foils, plus smooth white as the unfoiled profile. The colour you pick is the external face, with the same colour or smooth white on the inside. Liniar publish a wider foil catalogue, but availability, lead time and cost vary by colour, so we confirm before you order.
Can I have bars, horns or leaded glass?
Yes. Georgian bars sit inside the sealed unit, astragal bars are bonded to the glass face, mock sash horns dress the sash corners, and leaded glass comes in squares or diamonds. All of them are priced with the window rather than added afterwards.
Can you copy my existing window layout?
Usually, though an exact copy is not always the best answer. At survey we check escape, ventilation, handle reach, outside clearance and how the sightlines sit before the drawing is signed off.
What guarantee comes with them?
Two separate ones. Liniar guarantee the frame for ten years, and we guarantee our installation for ten years. They cover different things and come from different people, which is worth knowing if something ever needs putting right.
Are the frames recyclable?
Liniar describe their uPVC profiles as lead-free and recyclable at the end of their useful life. The profiles are designed, extruded and tested in Derbyshire.
From our case studies
Three casement jobs, start to finish.
uPVC casement window, Loughton
A badly fitted window left by a cowboy builder, replaced with a two-tone Liniar uPVC casement and finished cleanly inside and out.
Read case study
uPVC casement windows, Leighton Buzzard
A crisp white Liniar casement replacement in Leighton Buzzard, for warmer, brighter rooms and a tidier frontage.
Read case study
uPVC casement window, Broughton
A single two-tone Liniar casement in Broughton, replacing a boarded-up dormer window with a warm, secure one.
Read case studyRequest a quote
Tell us about the windows.
How many, what sort of property, and the main reason for replacing them. That is enough to start with.
What Milton Keynes homeowners say
Real reviews from real installations. Every one is public, so you can go and check them yourself.
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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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 Nicole 20 May 2025Shane and James fitted two sash windows for us at the front of our house and we are so pleased.
Read on Google Brigid Jordan 10 May 2025Everything went perfectly with our windows supplied and fitted.
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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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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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