Wood You Believe It?

Deceuninck’s MD Rob McGlennon considers whether a PVC-U flush casement window with authentic detailing can  be a true timber window alternative.

He writes, PVC-U window industry has always been about reinvention. Old single-glazed timber and aluminium windows and doors were replaced by energy efficient PVC-U double-glazed alternatives very early on, so sales of PVC-U windows and doors today are focused on replacing the replacements – primarily by focusing on energy efficiency.

However, PVC-U is gaining serious ground with opportunities presented by colour, security, aesthetics and sustainability.


But on the subject of heritage detailing

While profile design and foils can go a long way to mimicking timber and aluminium, PVC-U hasn’t always been able stand to toe-to-toe with those higher value alternatives. Now, and for some time, we are seeing evidence that high value PVC-U windows are replacing timber ones.

One of the reasons for this is that we have a much better proposition today than we did 50 years ago. And homeowners are buying into that. More specifically, they understand their homes and they are installing products that fit in with the age and the character of the property.

For example, sales of Deceuninck’s flush products continue to rise and now account for more than 40% of all products sold.

We are working on the basis that our flush casements are being sold into properties where the alternative would have been a timber window. While we have marketed on this idea, we’ve known that flush sash windows with mechanical joints and modern foils are typically an aspirational choice for PVC-U upgrades rather than genuine timber alternatives.

But that has clearly changed.



Our research confirms this. We commissioned YouGov to carry out a survey and the results support the popularity of flush windows. When presented with a choice of either a flush or storm casement, 62% of homeowners expressed a preference for the former.

In comparison, only 33% expressed a preference for a traditional storm sash, with a further 5% undecided.

YouGov found that while flush casements had universal appeal regardless of age, they were most popular among those in the 35-44 age group – and the preferred choice of 69% of respondents in this age group. Since this is a key demographic for the window industry, everything points to continuing growth in flush casement sales.


Driven by style

Combined with colour options it shifts the conversation with the end user away from one driven by price, to one driven by aesthetics and design.

And now that we are convinced that the potential market has expanded to beyond PVC-U replacements to include timber window replacements, the opportunities to add value and increase margin has never been greater.


Thermal performance

We launched our heritage flush sash window in 2016. It combines subtle balanced aesthetics, replicating traditional timber windows, with advanced thermal performance achieving WER of as high as A++ and U-values as low as 0.90W/m2K. air tightness is Class 4, water tightness Class E900, wind resistance AE2400.

PAS24 tested and Part Q approved, the flush sash can be fully welded or mechanically jointed and comes with a night vent facility, Georgian bar option and choice of traditional ironmongery.


Matching door

We added an open-out flush door sash alongside our flush window offer at the end of 2019. Fully suited with the Heritage 2800 system, it achieves U-values as low as 1.0W/m2K and DER A rating.

It is also PAS24 approved and can be welded or mechanically jointed, achieving class 4 600 Pa air permeability, class E1050 Pa water tightness (full frame) and class A3 1200 Pa wind resistance.



YouGov also found that more than 50% of respondents expressed a preference for a colour option - greys, including anthracite grey, agate grey and grey, accounted for a combined 17%; Irish oak and rosewood polled 7% and 6% respectively; greens, including Chartwell and sage green, recorded 4% and 1%; and black and cream each recorded 4%.

At a headline level, three-quarters of all respondents said that colour of windows was ‘very important’ in influencing their purchasing decisions.

Deceuninck offers 30+ colourways in stock and 20 additional colours in just 15 working days, while on average Deceuninck fabricators sell twice as much colour as their competitors.


Picture: A Deceuninck flush sash in wood effect with heritage window furniture.

Article written by Cathryn Ellis
12th September 2022


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