Single Double Glazed Window in Rowland's Castle

It depends on a few factors whether a new double glazed window will look different to existing ones. If your existing windows are very old, perhaps 10 years or more, then it’s likely that there will be some small differences.

The first thing to remember is that your double glazing is exposed to the elements as soon as it’s installed. So over time, unless you’re very good at cleaning and maintaining your windows, they’re likely to look a bit dirty. Window frames that are south-facing may also become slightly discoloured from the sun, so if you install a new window right next to it you might notice a difference.

Also, there have been lots of technical advances in windows over the years. If your existing windows are significantly older, you might notice a difference in the handles on openers, and if your existing windows were installed before 2010 they might not have trickle vents, which is an extra strip on the inside of your window to keep air flowing through your home. While it’s not a legal requirement for replacement windows to have trickle vents if the original one didn’t, it’s a good idea to have them installed as they help prevent condensation and mould.

The only truly noticeably different elements to a new double glazed window compared with existing ones are likely to be on the inside, which might not be a problem for you if you only have one window in a room. However, if you know the brand of your existing windows, you can ask your window installer if they can source the same ones. Even if they’ve been updated slightly, the difference should be minimal.

Yes, of course! It’s common for people to replace just one double glazed window. One reason that people want to replace one window is that the sealed unit inside has failed. You’ll know if this has happened because you’ll be able to see condensation on the inside of glass, which gets frustrating because you can’t wipe it away. In this case, you can choose to simply replace the sealed unit or the entire frame, which you might want to do if it’s looking past its best.

When you’re replacing just one double glazed window, if you know the brand of your current windows you could ask your installer if they can source the same ones. This will help to keep them looking as similar as possible, although if your existing windows are very old you may notice some discolouration on the exterior compared to the new one, and locks and trickle vents might look different.

Replacing just one double glazed window shouldn’t take a qualified window fitter long, and could cost as little as £400. If you want to simply replace the sealed unit, that may only cost around £250. You could try to fit a new window yourself, but it’s worth bearing in mind that all replacement windows need to be certified that they’ve been installed to meet building regulations, so you’ll need to apply to your local building control officer who will come and inspect the work then issue a certificate. If you ask an installer who is registered with a self-certification scheme (like FENSA) to fit the window for you, they can issue the certificate themselves when they’ve finished the work.

Double glazed windows are better than single glazed generally because they are more energy efficient. The clue’s in the name – double glazed windows have two panes of glass while single glazed windows only have one. In double glazed windows, there is a space between the two glass panes. This space is filled with inert gas or a tight vacuum, which helps to provide an extra level of insulation. That means that heat won’t escape your home easily, nor will it creep in, so you can keep your home at a more comfortable temperature.

The extra pane of glass also helps to increase your home’s security. Single glazing is pretty easy to smash through, whereas it will take much more effort to smash double glazing and will create more noise, so burglars might be put off.

Another reason why double glazed windows are better than single glazed ones is that they help to reduce noise. Of course, if you live by a busy road you’ll still hear some traffic noise, but it can be significantly reduced buy double glazing. In the same way that the inert gas in the middle of the two panes keeps heat in and the cold out, it also helps keep noise out.

With double glazing, you’ll also notice much less condensation. With single glazing, it’s common to see condensation on the inside of the windows, especially when the heating is on. This is because the outside of the window is cold, but the inside is warm. With double glazing, the insulation between the two panes stops there being such a difference in temperature between the inside and outside of the window.