A Better Bi-Fold

Schüco product manager, Adrienne Radcliffe, discusses the performance of the system supplier’s newest bi-fold door and how it was designed with part L in mind.

The 2021 changes to part L of the building regulations made it clear that glazing systems must do more, as part of a whole structure, to help meet future targets for efficient buildings. That is something we had in mind when developing the new Schüco AS FD bi-fold door range.

Launched in May 2022 with a 75mm option, the Schüco AS FD range already offered our slimmest sightlines and largest vent sizes on a bi-fold door with panel sizes of up to 3.5 metres high and 1.5 metres wide.

However, with the changes to the building regulations coming into effect in June 2022, we knew we needed to offer fabricators an ultra-thermally efficient product that would be instantly compliant with new requirements for bi-fold doors.


Giving them what they want

The AS FD range was developed for our UK and Ireland customers, using interviews with fabricators, architects and installers to understand what they wanted from a new Schüco bi-fold door. With that feedback in mind, we created a bi-fold door from scratch to deliver larger vent sizes, slimmer profiles, simplified fabrication and installation, and lower U-values.

The AS FD 90.HI, our highly insulated option, can achieve U-values of 1.0 W/m2K, well below the 1.2 W/m2K specified for windows and doors with a glazed area greater than 60% in the new part L.



Schüco is renowned for its thorough system testing. When we tested our system to determine product U-values, we used a centre pane with a Ug value of 0.7. Although this isn’t standard for the UK yet, it will become this in the future with the desire to drive down U values.

Glazing is the most important factor for hitting those lower U-values for windows and bi-fold and sliding doors. Our job as a system supplier is to make sure the frame is as airtight and thermally efficient as possible, which is what we did with the AS FD range.


Weight and movement

With glass being the main contributor to overall thermal performance, systems must be designed to support triple glazing which means being engineered to function successfully under more weight. So, one of our key considerations was achieving a highly energy-efficient bi-fold door that can still be easily manoeuvred.

The AS FD range was purposely engineered to be heavier and was designed with a heavy-duty roller carriage and solid stainless-steel track. It can accommodate up to nine panels, each with a maximum weight of 150kg and can still be moved quietly with one finger.


Luxury offering

Given the accelerated drive towards zero carbon and rising energy prices it isn’t surprising we are already seeing interest in the AS FD 90.HI from customers.

At the moment, we anticipate the door being mostly specified in luxury homes. It is also ideal for commercial use where ultra-energy efficiency is the goal and customers can take full advantage of the extremely large vent sizes on offer.


Be prepared

System suppliers should be offering these high-performing doors now to help fabricators react to changes to building regulations. In the next few years, demand will rise as more and more buildings are constructed with strict energy efficiency requirements and we should be prepared. With the Schüco AS FD range, we are.


Picture: Schüco’s AS FD bi-fold door.


Article written by Adrienne Radcliffe
19th February 2023


Related Articles