Triple glazing will replace double glazing within years, according to our Joint Managing Director of Cornwall Glass Manufacturing Mark Norcliffe.

The proposed Future Homes Standard (FHS), which is expected to come into force in 2025, will lead to more energy-efficient homes in England and Wales, and that is going to require a new approach to window and door design, according to Mark Norcliffe, Joint Managing Director of Cornwall Glass Manufacturing.

Windows going into newbuild homes from 2025 onwards are looking to achieve U-values of 0.8W/m2K, if the current proposals stand,” Mark explains. “While the FHS doesn’t apply to refurbishment projects, we can confidently expect the values to drop much lower than the 1.4W/m2K they are at the moment.

“We know that window systems are already struggling to achieve lower values with double-glazed units – especially aluminium – so why is no one talking seriously about triple-glazing?”

Triple glazing comes with a number of challenges. Yes, the potential to achieve lower U-values is greater, but this must be balanced against heavier units, deeper windows, more manpower, greater energy use in manufacturing and transportation, and greater pressure on manufacturing capabilities.

Mark Norcliffe- Joint Managing Director of Cornwall Glass Manufacturing

“When these issues were addressed over eight years ago, a ‘clever double glazed unit’ was more than capable of meeting the required U-values,” Mark says. “But we’ve moved on since then.”

Mark believes that the industry is burying its head in the sand, and pretending that the need for lower U-values are not going to happen.

“This isn’t going away,” he says. “As an industry, we need to be designing products that meet the stricter regulations now. At best, the industry can produce double glazed units with a centre-pane U-value of 1.0W/m2K, but the kinds of figures being discussed at present will require units with a centre-pane U-value as low as 0.6W/m2K, and this requires triple glazing.”

While triple glazing forms part of the overall product mix in the UK, the glass processing industry isn’t in a position to switch all orders from double to triple overnight.


“About 5% of what we currently supply is triple glazed. If that were to be increased, so that it represented the majority of our output, it would require 50% more glass and twice the amount of spacer bar and sealant, along with redesigned processes to accommodate the increased product, more scheduled deliveries because less product can be transported at once, and more lifting equipment.

“The impact would be significant. But that impact would be felt all the way through the supply chain, from more robust hardware to larger installation teams on site, and prices and lead times would increase significantly.

“And then you’ve got to factor in the supply issues and increased energy costs we are currently facing. Plus, the implications for security and overheating

– Parts Q and O of the Building Regulations – that need to be factored in. These will affect the cavity widths with thicker glass types and, ultimately, the U values.”

Cornwall Glass Manufacturing regularly invests in its operations to offer a very diverse range of options in IGUs and single glass, with our three manufacturing facilities in St Austell, Highbridge and Plymouth.

The latter provides the foundation for the manufacture of super-sized units in a wide range of solar control, acoustic and Low-E monolithic and laminated glass options. Our company also has heat soaking and jumbo cutting facilities, and we have invested in enhanced CNC and waterjet capabilities.

Our company is also planning the construction of a new £6m state-of-the-art facility in Highbridge in Somerset. Approximately £3.5m will be spent on a new furnace, a new unit line, new heat soak ovens, and a specialist lamination line, which will create 30 jobs.

“Demand in the UK is driven by homeowners and installers,” Mark says. “But when it comes to triple glazing, it could take up to two years to get products designed, and processes put in place to meet what we expect will be a huge uptick in the demand for triple glazing after 2025.

“We are already seeing some window systems – especially on the newbuild side – requiring triple glazing for their products to comply with the Building Regulations. This is only going to increase as the regulations tighten even further and, as an industry, we need to be talking about this now so that we are prepared.”


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