Wooden Double Glazing Sash Windows

Call Us Today 07565028004


Welcome to Sash Window Refurbish

Experts in Sash Windows Repair & Restoration, Timber Windows & Timber Doors in east midlands

Hello and thank you for your interest in our double-glazed traditional sash window service. All of our double-paned sash windows come with a lengthy warranty. These headings should help you navigate the wealth of information on this website regarding wooden double-glazed sash windows.

Wooden Sash Windows Double Glazed Designs


Validation of double glazing for existing wooden sash window

To what extent can I double-glaze the original sash windows in my home?

Adding double-pane glass to your original sash windows is usually possible. Your sash’s length is the sole limitation. They should be at least 35mm in size. By employing either traditional or slim double-glazed modules, sash windows may be retrofitted for double-glazing.

The cost to double-glaze a set of historic sash windows is often far lower than that of new windows.

In most cases, the savings you’ll get by sticking with the original sash will more than cover the additional expenses. If the original sash can’t be salvaged, the box frame may be recycled, and new sashes can be made to fit.

Double glazed unit

When we double-glaze original sash windows, we keep the original sash and add a new glazed unit inside.

An example of an old sash frame that has enough space for the double-glazed unit

If the old sash is too thin or structurally unsound to double-glaze, we may have new double-paned wooden sash windows made and installed in the original frame at a reasonable cost.

Replica Original Timber Sash Windows with Double Pane Glass - It's a complete swap, from the sash to the frame to the inside trim. While we don't often recommend it, there are times when a new sash window is necessary, such as for new construction or to meet planning requirements.

Timber Sash windows grew double panes of glass and blossomed

In light of recent advancements in glazing technology, double-glazing the building’s sash windows is now an actual possibility. If planning has denied your requests, we may still be able to assist you with alternative modifications.

A ten-year structural warranty and a five-year glazing guarantee are included with installing a new sash into the original frame or with the double glazing of existing sash windows.

Oversight of Double-Paned Sash Windows made of Wood

We can determine whether the current wooden windows can be used. In most cases, we can double-glaze your existing wooden sash windows without replacing the woodwork.

Double-glazed windows: a viable option for single-pane sash windows?

With the proper understanding and the use of slim-profile double glazing, the original sash windows seen in historic houses may be double-glazed.

The Process of Adding Double Glazing to Existing Wooden Windows

1.    Current single glazing be taken out

2.    Replace the existing sashes with new, slim-profile vacuum glazing

3.    To balance the additional weight of the new, heavier glass, adjust the cords and add more weights

4.    Make the current sashes draft-proof

Historic homes often feature single-glazed traditional sash windows. Condensation forms on single-paned windows in the colder winter months are traditional, and homeowners have to spend more for heating because of this inefficient window type. Furthermore, the acoustic insulation capabilities of single glazing could be better.

Requiring new sim-profile historical double glazing and retrofitting double glazing to timber windows entails removing and replacing the old glass.

To achieve the same level of thermal insulation as triple glazing, we employ small profile, vacuum-sealed modules. Using our techniques, you may be sure that the building’s original features will be conserved, that living circumstances will be improved, and that the service life of the building will be prolonged.

What are the benefits of double-paned glass in sash windows?

Double-glazed sash windows are more energy efficient

Effectiveness in retaining heat

Sash windows with two panes of glass are more energy efficient and lose less heat than those with a single pane of glass.

Low-E glass in a vacuum and slim-profile double glazing (only 5:7-10mm) provides the same thermal and insulating performance level as 36 mm triple glazing. Compared to conventional double glazing, the energy efficiency of aminated glass insulated with interior gases like Krypton and Argon is much higher than that of the norm.

Sash window double panes may be single or double, vacuum or triple-glazed

The thermal efficiency, thickness, and stability of several glazing alternatives for sash windows that may be retrofitted into the original sashes are compared.

We utilized a thermal camera to record the amount of heat lost through each kind of glass by inflating a box with hot air and placing it inside.

A quieter environment

Double glazing may be retrofitted onto existing original wooden windows to help muffle outside noise.

Our glass, for instance, offers superior acoustic performance compared to single glazing, cutting down on the sensation of a draft by more than a third.

This will be especially helpful if you live on a busy road and often wake up with the early morning commuters.


Because they are more challenging to break, double-paned windows and doors make a home safer. The toughened glass may be used to create the units (laminated glass or tempered) when necessary per code. This has even higher levels of safety.

Boost your home’s resale price

After some retrofitting, your home’s worth should rise as well. Since windows are one of the most significant elements of the house, double glazing may provide excellent returns on investment whether you want to sell your home soon or in the future.

Any wooden window can be upgraded to double glazing?

The most probable response is “yes.” Retrofitting double glazing to timber windows presents a number of difficulties. The size, shape, and condition of the window frames in question and the ease with which they may be accessed are all crucial factors.

Uniquely shaped

Speciality forms for slim-profile double-glazing units include curves, complete curves, trapezoids, and ovals.

  •      Dimensional Minimums and Maximums
  •      The largest dimensions allowed are 1.50 by 2.50 m/1.60 by 2.40 feet.
  •      Minimal: 0.20 meters x 0.20 meters

Compared to secondary panes or completely new replacements, double-glazing retrofits for sash windows may provide cost savings for homeowners.

When double-glazed, vacuum-sealed units are installed in the seshes, they blend in seamlessly. This new style of double-glazing makes historic sash windows seem identical to how they did when they were single-glazed.

Our experts can convert your existing sash windows with vacuum glass, making them as energy efficient as brand-new ones. On the other hand, new sash windows with normal double-glazed units and E-coating are 120–270% less efficient.

On the other hand, the supplementary glazing installed in sash windows alters the original windows’ overall aesthetic. There is a lot of inside window sill area it takes up, and it can be seen from the street.

Constant issues with double-paned sash windows

Poorly constructed frames that can’t support the added weight of double glass are a common problem we have to fix. To remedy this, we add concealed metal frameworks and stronger joints to preexisting frames, allowing them to support the added weight. Sash windows have their balancing systems and mechanisms fine-tuned and improved.

Authentic-looking double-glazing cannot be installed in the small rebates of original timber windows, a problem that other restoration businesses may encounter. We can securely and quickly operate inside the existing window rebates because of the advanced, ultra-thin double-glazing units we use. Thicker than a standard single pane by just 3 mm, our vacuum-sealed glazing provides the thermal benefits of triple-glazing despite its slim profile.

Can double glazing be used on windows in historic homes?

For the most part, it is yes. The development of technology and improvements in manufacturing techniques had allowed us to produce glazing pieces that were not feasible when your wood windows were first conceived and built.

Our double- and triple-paned windows and doors are thinner and stronger than standard options. In addition, their various benefits and enhanced performance may be attributed to the fact that they are vacuum-sealed.

Is there any impact of cutting-edge glass on your historic home? With this sleek profile, we can expertly install strengthened glass without sacrificing the look of the original. In most cases, the rebate depth is sufficient to accommodate the additional panes, with only minor adjustments required to maintain your windows’ authentic look and style.

How many distinct varieties of insulated glass exist?

When it comes to windows, we have a vast range of glazing choices to choose from. Each component has been meticulously chosen and placed to maximize utility and ease of use. You may get new double glazing like these from us to replace your old ones:

  •      Energy-Saving Low-E Glass
  •      Insulated, Bulletproof Glass
  •      Insulated Glass Units
  •      Restoring Normal Function

One disadvantage of adding more glass panes is the resulting mass increase. Fortunately, this won’t affect your windows’ reliability, stability, or security. Making the necessary modifications to the sashes’ weight and pulley system will ensure that they operate more smoothly, securely, and reliably than ever before.

We’ll rebalance your sash windows with new weights and replace and improve the sash cords on your windows. We inspect the pulleys and make any necessary repairs when we remove sashes to install new glass. When restoring hardwood frames and sashes, we also correct the sash joints.

Maintenance of sash windows and frames during retrofitting

We provide anything from sash window repair to a complete window refinishing service to ensure that your wooden windows are ready to support the increased weight of your glass upgrade.

Before installing the new vacuum glazing, we must fix the decaying window frames and sashes in the old box sash windows. The original timbers deteriorate from weather and wear over time, necessitating repair work. New glass may be safely installed after all rotted Wood in frames has been replaced, and all structural damage has been fixed.

Our crew can fortify original joinery and weak frames without altering their aesthetic value. Every one of our windows undergoes a meticulous inspection to guarantee a perfect fit and the highest efficiency.

In addition to installing double-glazing, we often implement draught-proofing solutions. The advantages of temperature, noise, and functionality have improved even more.

You can improve the quality of your living conditions, the value of your house, and the overall quality of the project by integrating services such as draught-proofing, decorations, repairs to woodwork, and double-glazing as part of the same project. These services complement one another and provide a streamlined, practical approach to restoration projects.


What is the lifespan of double glazing?

Even with contemporary double glazing, gas fills most of the space between the panes of glass. Argon gas is what you see here. This gas will eventually disperse and vanish. As a rule of thumb, this occurs every five years. However, here at Sash Window Refurbish, we employ cutting-edge vacuum double-glazing technology.

Compared to gas-filled double glazing, the lifespan of vacuum double glazing is substantially greater. Besides reducing noise and lasting 15 years, vacuum double glazing has several other advantages. Because of this, we have used Fineo for all of our window refurbishment jobs.

Compared to triple-glazed windows, its double-glazed shape gives the same protection against heat, noise, and moisture. It will insulate your house for a lot longer and uses less energy than standard double glazing.

When compared to double glazing, what is the function of secondary glazing?

Secondary glazing is an extra pane of glass installed inside an existing window frame on the interior of a building. Double glazing refers to an insulated window consisting of two independent panes of glass that are bonded together and then separated by an insulating spacer bar.

Insulation may be created by gassing or vacuum sealing the space between the panes of glass. Although it improves soundproofing, secondary glazing is ugly and alters the appearance of a building’s exterior compared to gas-filled double windows.

The aesthetics of your house are preserved while the heat loss is reduced by half with double glazing, slimmer than secondary windows. However, the acoustic and thermal insulation characteristics of double glazing are both outdone by high-quality vacuum double glazing. This is why our window refurbishment projects use vacuum double glazing.

What can I do to improve the efficiency of my currently installed but ageing windows?

Due to the inadequate level of insulation that they provide, older houses that only have one pane of glass in their windows may save a significant amount of energy and money. You could genuinely gain something by installing double windows.

However, there are restrictions on the kinds of double glazing that may be installed in many older homes and buildings. Double glazing installation, which can change the look of a listed structure, is prohibited. Sash Window

Refurbish can install double glazing into preexisting old sash window frames without compromising the aesthetics of a building because double glazing is only slightly thicker than single glazing. However, in some instances, approval from a conservation officer may be required to proceed with the installation.

If one wishes to prevent heat from entering a room, why is double glazing superior to single?

Having two panes of glass instead of one makes double glazing more effective in preventing heat loss. Two options are filling the interlayer space with gas or sealing it off to create a vacuum. This separates your home’s air from the outside environment. In other words, the barrier prevents the temperature difference between the air within and outside from being too great.

Insulation in your home’s walls and ceilings performs similarly to double-paned glass in windows. Therefore, the air inside your house will not change temperature as a consequence of the weather outside, thanks to the double glazing. For the same reasons, these glass panels reduce both noise and humidity.

What about secondary glazing? Is it more affordable than double-pane windows?

Secondary glazing, instead of double glazing, is more cost-effective. To be sure, secondary glazing is only sometimes the ideal choice: Put simply, secondary glazing doubles the glass area in an existing window. As a result, cranking open the window is a hassle. Having less of a window sill makes a room seem smaller.

The inside may be just as ugly as the outside, if not more so. While the cost reductions of secondary glazing are appealing, some negatives exist. In contrast to secondary glazing or even gas-filled double glazing, vacuum-sealed double glazing, which is the kind of double glazing that our company installs, does not affect the appearance of your home in any way while giving a higher level of protection and insulation.

Do I need to get my windows removed?

Not at all; we do everything right there on the spot.


My technician Andrew replaced all my sash windows that had rotten sills. Accessing the rotten sills was not an easy task. He explained to me what needed to be done in order to fix the problem. He is a great person and I’m happy that he was the one who did the job. He is reliable, tidy, friendly and very professional. I highly recommend him.



I hired Andrew and Alex a while back to repair my damaged sash windows. They were was very considerate and very patient as he did his job. A few days ago, I had another problem with one of my sash lock keys and I called him again to come and fix the problem. I’m very impressed that Liam responded quickly and he not only fixed the problem but he also gave me a spare key. What a great after sales service!

Alan W.


I’m very impressed with the new windows that Andrew installed and also the reconditioning job that he did on other sash windows. The quality of his work is by far more superior than what we got when we hired another company a few years back. We will certainly hire him again if any window work arises

Kelly (Sleaford)


Our decorator referred us to Andrew because some of the work needed a window expert. Andrew together with our decorator did a fantastic job. The work was done efficiently and to the highest standards. Andrew is understanding, committed and very professional. I recommend him without any hesitation.

Steaven Reader


Alex did a great job in fixing windows in our terraced house. The windows were broken, frames damaged and the wood was also rotten. Alex's job was high quality and he did it pretty fast. I was also very impressed that he was considerate of my son’s asthma condition and maintained cleanliness. Top work.



Andrew just recently replaced three sash windows in my Edwardian house. He also repaired and replaced some sills and draught proofed three windows. In addition to that, he also did some carpentry work. What I like the most about Liam is that he did a clean job. He is very professional and always updated me about the timescales and costs. He also did his job with minimal disruptions. I highly recommend him.

Cris M.