Sash Windows – Timber vs uPVC


Sash windows are currently extremely popular in the UK, as they were in centuries past. Historically, sash windows became less popular as they were known to be high maintenance. There was also a time when ‘window tax’ was active in the UK, making this style of window much more expensive. Now, we don’t have window taxes and advances in tech and building materials mean the windows aren’t as high maintenance.

There have been a lot of technological advances since those old days, and sash windows are making a comeback all over the nation. They’re better looking, adding a touch of class to buildings, and are also actually longer lasting than regular windows. They’re also more reliable, and more efficient at cooling rooms when opened, because opening both the top and bottom creates a current, drawing hot air out of the room and cool air in. Windows with one opening do not do this.

A big question we see coming up is whether to get timber or uPVC sash windows. The frame material can affect the window a lot, so let’s take a look at how.


 The look of your windows is likely to have a big impact on your decision, as many people want sash windows because they look nicer than other types of window. They have a classical, exclusive look. For this reason, most people prefer to choose timber frames, as they keep the home looking more sophisticated and original.

Timber also doesn’t fade under the sun’s rays like uPVC does, so timber frames can be kept looking new for a lot longer. Timber is much easier to restore by re-varnishing or painting as well.


Timber is a natural insulator, while uPVC is not. This means a timber frame will be better at holding in heat, and keeping out cold. With modern glass, and double/triple glazing, this can make timber frame windows very effective insulators.


When it comes to durability, timber wins hands down. UPVC windows will last around 35 years on average, based on past studies, whilst wooded frames last for 60-80 years, or more, with the right maintenance. There are several old style sash windows around the UK that are over 100 years old. With the knowledge and skills we have today, new timber sash windows could last several lifetimes. Of course, this would require taking good care of the windows.

Environmental Factors

 It’s common knowledge that the production of plastics is bad for the environment. uPVC is not biodegradable, and is tough to recycle. Timber is an easily recycled and reused material. It is also completely biodegradable. The production of timber in terms of trees can be offset by using chain of custody forests. These forests are closely managed to ensure new trees are being planted and maintained, and that old trees are not being taken down too fast to be replaced.


Cost is a complicated issue for sash windows. UPVC are cheaper to buy upfront, and many people buy them for this reason. However, keep in mind that uPVC repairs cost more and are harder to do, so if there’s ever any damage to your windows it will cost more to repair if they are uPVC compared to timber.

Also, you need to consider the lifespan of the windows. UPVC are cheaper to buy upfront, though are only expected to last around 35 years (according to the Building Research Company). Timber frames can last well beyond this when they’re well looked after.


 For low maintenance windows, uPVC is the way to go. They don’t require much maintenance, and will usually last reliably for 30+ years with very minor maintenance. Timber framed sash windows need a bit more looking after.

Timber frames should be checked regularly for any cracks in the coating, as they have to be well protected from the sun and the weather. Not doing this can lead the frames to rot, which means you’ll need to either replace, or hire a specialist for costly repairs. Outside of this, regular cleaning and removal of dust, dirt and grime will be required.

Other Considerations

 Modern sash windows are not the same as those fitted hundreds of years ago. They are made in a much more reliable way, and many options are available for them. You can get sash windows with different types of locking mechanisms, catches, layouts, and a variety of security features.

These features can change many of the above factors, so they should also be considered. For example, maybe environmental impact is of no concern to you, while appearance is. Depending on the look you’re going for, the features and options you choose for your window may mean one type of frame looks better than the other.

Ultimately, you need to consider what’s most important to you, and then make your choice based on the above factors and your personal preferences.

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