Fenster Glazing
Replacement Glass for Misted and Blown Double Glazing
Replacement glazing is a new sealed unit, made to fit the frame you already have. When the seal around a unit fails, damp air gets into the gap between the panes and mists the glass from a side no cloth will ever reach. We measure the opening, check what the position needs and fit a new unit into the existing frame.
What has happened
The water is on the inside, which is why cleaning it does nothing.
A double glazed unit is two panes of glass held apart by a spacer and sealed all the way round. The seal is the part that fails. Once it goes, damp air gets into the gap, and on a cold morning it condenses against the glass where no cloth will ever reach it.
That is the haze, the tide marks and the streaks that come back however many times the window is cleaned. Cloudy, foggy, steamed up: they are all the same failure. The frame around it is usually still perfectly good, which is why the glass on its own is the job.
- A pane that mists over when the weather turns, then clears again
- Streaks and tide marks that do not wipe off from either side
- Often one pane in a window while the ones beside it stay clear
Before and after
The same window, five minutes apart.
Both photographs are ours, taken on the same afternoon from the same spot. Drag the handle across and watch the middle pane come back.
Look at the panes either side of it. They were clear the whole time, in both photographs, because only the middle unit had failed. That is what a failed seal looks like next to a good one, in the same window and the same light.
On the day
The frame stays exactly where it is.
The beads come off, the old unit lifts out, the new one goes in and the beads go back. The beads and gaskets already on your window are almost always the ones that go back on it, so the frame, the hinges, the handles and the locks are all left as they were.
It is a quiet job, and we leave the room as we found it.
- An hour at most for a single unit, longer where there are several
- We need to reach the window from inside and out
- The old glass leaves with us
What we can reglaze
Your frame stays, whatever it is made of.
A repair is the hardware, the alignment or the seals. This is the glass itself, made to your measurements. Plenty of jobs need both, and the same engineers price and do them together. Larger and commercial work goes through commercial replacement glazing.
- uPVC, aluminium and timber
- Beaded frames and putty glazed timber both. The unit is measured to the frame it is going into, and the beads and gaskets already on it are almost always the ones that go back.
- Windows and doors
- A pane in a door is the same job as a pane in a window, and a Velux takes a sealed unit swap in the same way. Doors and low panes get checked for toughened or laminated glass before anything is ordered.
- Leaded, Georgian and decorative
- A leaded diamond pattern or Georgian bars can be matched into the new unit, so a period window comes back looking like the one that failed rather than a flat pane in an old frame.
- Like for like, single, double or triple
- What the frame already holds is what goes back into it, cut and fitted the same way. A single pane returns as a single pane, a double as a double and a triple as a triple.
If the frame is rotten or no longer closing properly, we will say so rather than sell you glass for it. The survey is free either way.
Upgrades
New glass is a chance to change what the window does.
A unit is built to order, so what goes inside it is up to you. Blinds sealed into the glass, obscure glass where you want privacy, an aperture for the cat, or glass that cuts noise, heat or glare. The frame, the hinges and the handles all stay as they are.
It does not have to be a failed unit. If the glass in a window that is working perfectly well is not doing what you want, we can change that unit on its own and leave the rest of the window alone.
Integral blinds are the one people ask about most. The blind sits sealed inside the unit, so there is nothing hanging in the room and nothing to dust, and it goes into most windows and doors including frames we never fitted in the first place.
- Integral blinds, into most windows and doors
- Obscure glass where a bathroom or a landing wants privacy
- A cat or dog flap aperture cut into the new unit
- Toughened, laminated, acoustic and solar control glass
Each unit is made to your measurements, so whatever you want in it is chosen when it is ordered.
Where we work
Replacement glass across Milton Keynes and the towns around it.
Bletchley, Wolverton, Stony Stratford, Newport Pagnell and Woburn Sands among them, and out into the wider Buckinghamshire, Bedfordshire and Northamptonshire area. Glass is measured on site and made to the opening it is going into, so the distance matters less than the access does.
Every sealed unit we fit carries a ten year guarantee from the manufacturer that made it.
Our work
Units we have changed.
Every photograph here is a Fenster job, taken on the day. The two of the same room are before and after on one window. Click any image for a closer look. Every photograph is a Fenster job. Tap any for a closer look.
Product questions
FAQs about replacement glazing
Can misted double glazing be replaced without a new window?
Usually, yes. If the frame is sound and still opening and closing properly, the failed unit comes out and a new one made to the same size goes back into it. The frame, the hinges and the handles all stay. Where the frame is rotten or no longer closing properly we will tell you what we think is worth doing.
Why does cleaning it make no difference?
Because the moisture is sealed between the two panes rather than on either surface. Once the seal has failed, damp air gets into that gap and condenses against the inside of the glass, which is why the haze comes back whatever you clean it with and why it often looks worse on a cold morning.
How long does it take?
Around one to two weeks from the order, because every unit is made to your measurements. We measure first, then come back to fit, and a single unit takes an hour at most once we are there. We need to get to the window from inside and out, and the old glass leaves with us.
What does it cost?
Units start at £170 plus VAT, fitted, and the price moves with the size of the unit, the glass in it and how many there are. Send rough sizes and a photograph and we can usually give you a price without coming out, or price it yourself on our online tool. There is no minimum.
Will new glass make the room warmer?
A new unit performs the way a working one should, so where the old one had failed you will notice it. How much difference it makes overall depends on the frame around it, which is why we would rather look at the window than promise a figure. If warmth across the whole house is the aim, that is a conversation about the windows rather than the glass, and we will say so.
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
Send rough sizes and a photograph and we can usually price it without coming out, or price it yourself on the online tool. There is no minimum: one unit is a job worth doing.
Technical survey
Once you go ahead we come and measure before anything is ordered: the glass size, the spacer, the frame it goes back into and whether the position calls for toughened or laminated. The survey is free.
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
Ten years on the sealed unit, which is the guarantee the manufacturer gives us and we pass straight on. Anything afterwards you ring us rather than a call centre, and you are talking to the same people who fitted it.
What Milton Keynes homeowners say
Real reviews from real installations. Every one is public, so you can go and check them yourself.
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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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.
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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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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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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.
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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Tell us which window it is.
Rough sizes and a photograph are usually enough for us to price it without coming out. Tell us how many units and roughly how big, and say if anything about the glass wants changing while it is made.
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