Roseview Windows has cut the possible U-value of its Heritage and Ultimate Rose sash windows from 1.4W/m2K to 1.2 without triple or vacuum glazing, using ThermoVFlex technology developed by Rehau.
Managing director Richard Burrells explained: “Until now the only way to reduce the u-value on sash windows below 1.4 W/m2K was with triple or vacuum glazing. Both options carry problems, including cost, weight and practicality.
“ThermoVFlex allows us to manufacture a Heritage or Ultimate Rose sash window with a 1.2 u-value, while using the same IGUs that previously gave us 1.4. It costs much less than triple glazing and vacuum units and doesn’t impose restrictions on the use of safety glass, patterns or astragal bars.”
He continued: “This is a major advance in sash window technology. While the Future Homes Standard is maintaining current U-value requirements, finding economically viable ways of improving energy efficiency remains important. For new-builds in particular, this gives customers more room to manoeuvre with their limiting values.”
Russell Hand, head of product management and technical, Rehau Window Solutions UK added: “Our latest development is a patented technology that can reduce the U-value of our windows without the need for specialist glazing. It’s a significant step which is particularly relevant for sash windows and so it made perfect sense to work with long-standing Rehau customer Roseview to launch this exciting new technology.”
