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Can original sash windows be double glazed?

February 10, 2023

Sash windows are a timeless piece of engineering that can be found on many traditional homes.

All that style and elegance, however, can come at a cost, with ageing designs often draughty, leaky, and not exactly energy efficient. 

Replacing original sash windows altogether is an option; although newer windows are not always in keeping with the design style. And replacement costs can be off putting.  

If you’re against ripping out your original windows, and don’t want to ruin the look of your period property, there is a solution. 

Installing double glazing to your sash windows will retain the traditional style, improve comfort and energy efficiency; all while keeping costs down. 

Factors affecting whether double glazing is possible on original sash windows

  1. Age. A crucial factor is the age of the sash windows if you’re considering double glazing. The older the windows are, the less feasible it may be to upgrade them in this way. Historic windows in particular may not be strong enough to support the weight of the double glazing, and their frames may not be the right depth to be able to house the thicker units. In this instance, it may be necessary to completely replace the window.
  2. Efficiency. For double glazing to be installed, window frames must have a certain level of efficiency. If the sash windows are in good condition, then they may be suitable. However, if they’re draughty or inefficient, it may not be worth the investment. This is because double glazing will not significantly improve the efficiency of inefficient windows.
  3. Likelihood of future rotting. Sash windows that are in poor condition, or have been previously damaged, are at risk of rotting. Rot can cause significant damage to the windows as well as to the structure of the building. If the windows are likely to suffer from rot in the future, replacement is probably the best option.
  4. Type of sash window. You need to consider the type of window you have, as different types of sash windows have different requirements for double glazing. If yours boasts an original thin single glazed unit, it may not be possible to replace it with a double-glazed unit without affecting the classic look of the window.
  5. Building regulations. In some conservation areas, there may be certain restrictions on the types of windows that can be installed. It’s important to check with a professional before making any modifications to your windows to ensure that they are compliant.

How long does it take to double glaze a sash window? 

The time it takes to double glaze a sash window can vary greatly depending on a number of factors, including the size and complexity of the window, the type of double glazing being installed, and the experience of the installer. 

It could take anywhere from a couple of hours to a full day to double glaze a sash window, depending on the specifics of the project. 

However, the most important factor is ensuring the quality and experience of the installer. A professional installer will be able to complete the job more quickly and efficiently.

Want to speak to the experts?

Age, energy efficiency, building regulations, the likelihood of future rotting.

When it comes to sash windows and installing double glazing, there’s certainly a lot to consider.

And that’s before you even begin to price everything up, or look at timescales. 

If you are considering a sash window upgrade, it’s vitally important you seek out the expertise of a trusted and experienced company. 

At VEKA, we are committed to providing high-quality products and expert installation services to ensure that your sash windows are functioning efficiently and effectively for years to come. 

Our experienced team of experts will work with you every step of the way to make sure your windows are the perfect fit for your home and your lifestyle.