Increase thermal efficiency with new double glazed windows

At Sash Window Conservation, it’s our goal to provide customers with the best quality windows, whilst being respectful of the history or heritage aesthetic of a building.

With this in mind, we will work with you throughout your purchasing journey to ensure that both your design and performance goals are achieved.

Product Features

Why choose new double glazed windows

How would your project benefit from new double glazed windows?

Installing our new, traditionally crafted double glazed windows will ensure that your project benefits from effective thermal insulation, saving inhabitants money on bills and also increasing noise insulation.

Customers will also benefit from modern security features such as restrictor bolts and vent locks, and have the option to upgrade to acoustic glazing or our Sash Secure 240 product depending on your bespoke requirements.


Installing new double glazed windows will ensure that your project has the latest in security, with the option of key operated locks and security/safety glass. We also offer our Sash Secure 240 product for projects with high security requirements.


Our double glazed windows can be made to your specification, so long as they are traditional. If required, we can make full sized samples and models to help you achieve planning permission and meet local authority requirements in our Kent-based factory.


Installing new double glazed windows will increase your project’s thermal efficiency and noise insulation. Our products offer U-values as low as 1.2 W/m2/K which is within building standard requirements and we also offer acoustic windows.

Our Buying Process

At Sash Window Conservation, we aim to keep the buying process as simple and straightforward as possible, giving you the peace of mind to focus on your project. Read more about how it works below.

Share your goal with us

When you contact us, we will arrange a call to run through your specification and ideas. You can then share any documents or drawings you have of your project, and what you’d like to achieve with the end result.

We will take this and see what we think is realistic and would work best for your project, timescale and budget.

We will then share our thoughts with you and see how they match up with your vision.

landscape image of university of the arts in london using traditional sash windows

We may pay you a visit

We may arrange a visit to ensure that the bespoke design or refurbishment plan that we have in mind will be just right and fit with the rest of the building and its neighbours.

We can then make any necessary adjustments and begin preparing your bespoke quote.

Canal side of Jamie Oliver HQ, Regent's Canal, King's Cross using new windows retaining the traditional sash window aesthetic

Providing your quote

Once your specification and requirements have been agreed upon, we will put together a bespoke quote. This will include a price per window so that you know exactly what you’re paying for, a range of options to ensure you choose the best solution for your needs, together with our own recommendations based on your individual project.

Our quote will also suggest ways in which you could save money, to help you to stay within your agreed budget, whilst getting maximum value from your order.

Society of Antiquaries building using traditional timber sash windows, also showing the arched entrance

Creating your bespoke design

Following your approval of our quote, we will get to work on creating your bespoke design in our Staplehurst factory.

Once our team have created a selection of samples, you will be offered the chance to visit our factory to review them before we go ahead with the final product.

university of the arts in london using traditional sash windows
Close up image of an arched window

New double glazed windows for your bespoke heritage project

Our full surveying and reporting service helps us work together with you to ensure your windows achieve the traditional heritage aesthetic that you’re aiming for, whilst our bespoke advice means you will always get best value for money. Our careful craftsmanship means that although brand new, your windows will not look out of place next to those originally installed.

Having our own joinery factory and full team onsite in Staplehurst, Kent, means we can provide full scale models and samples to help achieve planning permission for your project, and also offer our customers a factory visit to check you’re happy with the product we’ve designed.

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More economic but just as stylish

Though installing our new double glazed windows will inevitably increase the thermal efficiency of your project, also saving its future inhabitants money on their bills, you can rest assured that this will not affect the heritage aesthetic of the product.

With U-values as low as 1.2 (W/m2/K), our new double glazed windows are more than compliant with modern environmental standards, whilst maintaining the historic aesthetics and integrity of your project’s traditional design.
We work together alongside main contractors and architects to ensure your chosen design will achieve planning permission and meet London Authority design standards where applicable.

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Double glazed windows with a traditional sash window design

Case Studies

See how our bespoke heritage products have enhanced previous projects with testimonials from our valued customers below.

Who we’ve worked with