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When it comes to installing new windows in your home, it seems like the obvious thing to focus on the glazing itself. But the window frames are just as important and are rarely afforded the same level of consideration.

Not only do the frames alter the look and feel of your windows but they also have an impact on energy efficiency.

The choice of frame is particularly important when you’re opting for sash windows, as the frame takes up so much of the surface area and is responsible for the majority of the window’s aesthetic.

The two main modern choices when it comes to window frames are classic timber or more modern and affordable uPVC and here, we’ll be putting both timber and uPVC sash windows under the microscope.


Timber sash windows will always look incredible in older properties, as uPVC could potentially look a little out of place.

There is the option of uPVC with a woodgrain effect but when it comes to sash windows, it’ll be easy to spot the difference on closer inspection. A timber sash frame will also generally be thinner and look more organic.

More benefits:

  • It looks stunning and has a classic texture and feel to it.
  • It’s a natural insulator, and when combined with double glazing, you’ll retain ample heat in your home.
  • You might need to give them a little love and attention every few years but if you do, these frames could last as long as you do!
  • They can be finished in a range of different stains for a variety of effects.
  • Timber is a natural resource so is a more sustainable material than uPVC.


There is a common misconception that uPVC is more energy-efficient than timber simply because it’s a more modern and completely man-made material. This is only because many older timber framed sash windows had single glazing though. In fact, timber is a naturally insulative material. Where the rumours do ring true, however, is in how much easier uPVC is to maintain and clean.

More benefits:

  • uPVC is a much more affordable option than timber.
  • As we’ve already mentioned, cleaning it is really simple. As simple, in fact, as taking a cloth and soapy water to it every now and again. Given the little nooks and crannies, you’ll find in most sash window designs, it’s very convenient to have frames that are easy to clean.
  • uPVC sash window frames are designed with multiple chambers that trap the heat in your home.
  • They can emulate the appearance of timber sans windows for a fraction of the price.
  • Whereas timber can crack over time, uPVC is going to hold its good looks for longer with no maintenance. Though white uPVC can yellow over time.

Both are great options and which you opt for will depend not only on your budget and the existing design of your home but on your individual tastes and preferences. Generally speaking though, replacing timber with uPVC is always going to be a decision you live to regret.