Sash Windows

Can you have double glazed sash windows?

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Contemporary technology (potentially) meets heritage design

If you are excited about the idea of having sash windows fitted on your residential property, it’s probably because your home hews to a traditional look or you would like to bring a touch of heritage class to a modern property. However, the centuries-old design of sash windows could lead you to wonder whether they could be fitted with double glazing, a much more modern phenomenon.

What are double glazed windows?

A double glazed window is a window with two panes of glass rather than just one pane. In the window, the two sheets of glass are kept apart by a spacer bar leaving an air gap filled with insulating gas, allowing more of the room’s heat to be retained.

How expensive are double glazed sash windows?

This will depend on various factors, including the size and style of the windows and the age of the property where they will be fitted. However, while double glazing has a higher upfront cost than single glazing, it is more thermally efficient and so can be cheaper over the long run.

A modern solution to a traditional problem

If you have a particularly old home, such as one originally built in the Georgian, Victorian or Edwardian period, then the property probably has sash windows. Windows of this type are instantly recognisable from their panels – or “sashes” – which can be slid to open or close the unit. However, whether your window slashes slide vertically or horizontally, you probably don’t have double glazing.

Double glazing is a relatively recent invention, even if its exact origins are somewhat shrouded in mystery. It’s generally thought that the Scottish initially experimented with double glazing back in Victorian times, when harsh weather led Scottish homes’ existing, single-paned windows to plummet in temperature and make disconcerting rattling sounds. Such problems can continue to beset homes not fitted with double glazing.

What benefits can double glazing bring?

Most people who choose double glazing probably do so to improve their home’s heat retention – and, indeed, double glazing does meet this purpose while preventing cold air from leaking into the building and threatening the comfortable warmth in which the home’s occupants live. However, double glazing has been credited with a range of other practical benefits as well – like these…

  • Preventing too much external noise from being heard inside the home
  • Reducing the amount of condensation that forms on the inside of the window
  • Limiting the required level of energy expenditure in the home
  • Lowering the expense of the household’s energy bills
  • Increasing the property’s market value

However, you should also consider that, as double glazed windows can be designed bespoke, they aren’t necessarily identical in all of the benefits they can bring. For example, in fitting different sash windows with different glass products, we can help different clients to tackle different issues– like a bedroom bathed in too much sunshine, a home office overly exposed to outside noise… and so on.

Can double glazed sash windows be installed on period properties?

While this is possible in many instances, you might need planning permission if your home is a listed building or within a conservation area. To obtain this permission, you could be required to prove that the single-glazed windows you are eager to replace are beyond repair.

Would triple glazing also be an option for a sash window?

While double glazing can significantly improve your home’s energy ratings, triple glazing can be even better on this score – and it’s yet another glazing option we offer for sash windows. Triple glazing can also help to muffle noise from outside if you live in a particularly busy area.

How to fit double glazed sash windows in a period-sensitive way

It’s increasingly obvious, then, why you would probably strongly consider double glazing for sash windows on an old property. Many homes like this date from a time before double glazing and its myriad of benefits were commonplace, leaving these buildings inefficient – at least by modern standards – in how they use energy to stay warm to a sufficiently comfortable extent.

Nonetheless, there remains the question of how double glazing can be integrated in a way that, as may be required by planning regulations, does not noticeably harm the home’s historical character. The good news is that you might not need to do away with the existing window enclosure. However, using thick bars to divide up small units of double glazing can leave the window looking clumsy.

Fortunately, by dipping into our extensive experience of designing and building double glazed sash windows, we can find creative solutions to problems like these. For example, to overcome the problem cited just above, we could bond mock bars onto either side of just one double glazed unit as well as add spacer bars between the glass sheets.

What if your existing windows are beyond repair?

Some people choose to upgrade to double glazing simply to enjoy benefits they would deem nice-to-haves. However, other people might decide on splashing out on double glazing because their existing windows are damaged beyond repair and so clearly need replacing anyway. If you are in this situation, would it really be possible for you to source new window frames in an “old” style?

The reassuring answer is yes. We could, for example, provide your London home with uPVC windows in a wood-effect finish visually akin to the previous window. Nonetheless, if you live in a listed building or conservation area, a genuine timber sash window might be the only real option open to you. This is because old windows often come in intricate designs difficult to replicate with plastic.

Why should you prioritise getting new timber windows?

It’s important to acknowledge that uPVC sash windows still come with an array of notable benefits. They are – for example – energy-efficient, easy to maintain and cheaper than timber. However, as switching to uPVC sash windows for a period home can be heavily frowned upon, you should look into getting double glazed timber windows first – especially as they would have these advantages…

  • An impressive level of durability
  • Highly effective insulation
  • A long lifespan if suitably maintained
  • A wide choice of paint colours and stains for the window frame’s finish

You also don’t need to fear struggling to preserve the condition of your new timber sash windows for the long haul. In recent years, windows of this type have been carefully refined to ensure that the days of inconveniently high-maintenance timber windows are now very much in the past.

How expensive are double glazed sash windows?

This will depend on various factors, including the size and style of the windows and the age of the property where they will be fitted. However, while double glazing has a higher upfront cost than single glazing, it is more thermally efficient and so can be cheaper over the long run.

Would triple glazing also be an option for a sash window?

While double glazing can significantly improve your home’s energy ratings, triple glazing can be even better on this score – and it’s yet another glazing option we offer for sash windows. Triple glazing can also help to muffle noise from outside if you live in a particularly busy area.