The window and door market appears to be grappling with competing forces: more light, slim sight lines and high-end aesthetics are being balanced with improved thermal performance, better security and ease of installation.
“There does appear to be conflicting pressures on window and door design,” observes Deceuninck Aluminium’s Director Nigel Headford, “but that’s only because many companies’ experiences of aluminium and window door design is limited to older systems which are being periodically updated to meet the changing Building Regulations.”
The Building Regulations were updated in June 2022, which meant windows and doors with a glazed area of greater than 60% going into newbuild properties or extensions had to achieve U-values of 1.2W/m2K for windows. This is expected to drop to around 0.8W/m2K when the Future Homes Standard comes into force in 2025.
“In many cases, even relatively new aluminium bi-folding doors – which tick the boxes for aesthetics, performance and security – struggle to meet the new requirements, with triple glazing often being pushed as a method of compliance,” Nigel says.
“Older systems were typically designed for a double-glazed unit, so there’s a maximum width of unit you can get into the frames. So, the question is not about the number of panes of glass, but how deep you can go, and with older systems you are often limited to a 28mm-32mm unit.”
Nigel argues that while aluminium remains desirable, many products will struggle to remain relevant. The Decalu88 Bi-Folding Door from Deceuninck Aluminium, on the other hand, can incorporate units with thickness ranging from 12mm to 62mm, giving you greater control over the thermal performance.
“If we went for a standard centre-pane U-value of 1.0W/m2K on the bi-folding door, we can achieve an overall U-value of 1.3W/m2K,” he says.
“This means our door can comply with the 2022 Part L revisions for refurbishment with a double-glazed unit. And if we went for a 0.4W/m2K centre-pane U-value, we can achieve an overall performance of 0.68W/m2K with a triple-glazed unit. That’s based on a 4m x 3m bi-folding door, and able to meet the expected values in 2025.”
If a triple glazed unit was used to improve the thermal performance of older systems, consideration would need to be made for the extra weight placed on the hardware.
“Most bi-folding doors on the market have a maximum weight of 100kg-150kg,” Nigel says. “So, if you are going to put in triple glazing then you are probably going to go over that maximum weight, which is going to limit the size of the door.”
The rollers on the Deceuninck system are designed to take 200kg a leaf. This is a key strategic design because weight is an issue that could rear its head further in years to come.
“We may be looking at acoustic/laminate glass in the future, especially with security,” Nigel says. “You are already looking at laminate glass being installed in all doors. So, if you want to keep the size, and incorporate a 62mm unit, then you need a heavy-duty roller and hinges to cope with it.”
The Deceuninck Decalu88 Bi-folding Door was also designed to be straightforward to install, and features such as the pre-installed gasket are now legendary, according to Nigel. Installers report saving 30-40 minutes per door, because they don’t have to install the gaskets.