Sustainable, flush and energy efficient

Kevin Warner, sales and marketing director of Profine UK and the Kömmerling brand, talks about the heritage market for flush casement windows and the requirement for better energy efficiency and also improved sustainability credentials.

The evolution of the flush casement window has been a revelation in the industry and has opened up the market for heritage applications with PVC-U products, a sector historically dominated by timber.

We’re also seeing a big trend towards equal sightlines too, with dummy sashes now becoming the norm, reducing the need for fabricators to reverse butt weld on window combinations, a process unique to the UK market.

With a shallower front to back dimension, most flush sash profiles are less energy efficient than their lipped, or standard casement counterparts. This has considerable implications with the new building regulations which come into force in just a matter of weeks. We planned ahead with our flush sash profile and as a tested and simulated window it achieves a U-value of 1.2 W/(m²K) as standard and is leading the way in a 70mm platform.

Our C70 and O70 platforms with standard sashes also achieve this same standard, though the flush sash profile makes up for its lack of depth with a sixth and indeed, seventh pseudo chamber. Without doubt, when building regulations again change as early as 2025 the requirements for a 1.2 U-value in new build will go lower as will the 1.4 requirement for the replacement market. We’re already planning for the future as is the Kömmerling way and thanks to the considerable resources across the Profine Group.

We believe that heritage applications, enhanced energy efficiency credentials and the green agenda can be addressed in a 70mm flush sash product proposition, but only if the overall product and business strategies are aligned. We are one of a very few companies in the UK that can boast a closed loop recycling programme and at present we believe that we’re the only PVC-U systems company in the UK proving a U-value of 1.2W/(m²K) as standard across all 70mm platforms and that includes our sister brand Legend and also our innovative PremiLine patio door when triple glazed.

But beyond the immediate sash profile design and specification, we can also offer an authentic plant on Georgian bar, range of period-inspired hardware including the Regal range of monkey tail and pear drop handles and other important ancillaries.

We’ve also developed an innovative concealed mullion option which is invisible from the outside and provides just a 36mm sightline to the internal face, offering an outstanding design option for a cottage window and is available in white or laminated, along with matching end caps.

As part of the design process, we’ve also added material into our flush sash profile, for better production processing with the new TimberWeld, MechWeld and seamless welding technologies, the former two options perfect for the heritage market. This has been achieved by working closely with our manufacturing partners and with leading machinery companies as part of the product development programme.

As part of our heritage proposition, colour and finish have also been high up on the agenda prior to launch and so we’re carrying a number of finishes from stock including Agate Grey and smooth Anthracite Grey on a grey base, out of a colour programme of over 40 all available on a short lead-time.

The flush sash window will also form an important part of our large-scale exhibition stand at the FIT Show this May at The NEC Birmingham. After a three year wait for our beloved trade show, we believe it could be one of the most exciting events for some years, despite the events happening across the world at present.

Sustainability, energy efficiency and heritage flush sash window design can all work in harmony to open up a new market for heritage inspired glazing. Not all consumers want the contemporary/urban appeal when it comes to window and door design but yearn for something that has more than a little nod to yesteryear. We hope to see you at the show where flush will be on display in several different variants, along with other products and brand initiatives.