The Wood Window Alliance (WWA) is urging architects and builders to take advantage of the design and technical versatility of timber window frames in meeting latest energy rating standards, rather than take a ‘one size fits all’ approach.
In a campaign targeting the specifier trade press, the WWA highlights that window energy ratings (WER) are assessed on a combination of heat loss (U-value), solar gain (G-value) and heat loss from leakage (L-value). This means different balances can be struck between the three criteria.
“For instance, for a large south-facing window, it may be better to specify one with a low solar gain to stop summer overheating and lower U-value to keep heat in during winter,” said WWA chairman Sean Parnaby.
Currently, he said, there is a danger of the building sector opting for a uniform balance of the various WER criteria. This could be wasteful and limit design flexibility.
“We need an intelligent debate about energy efficiency requirements to help specifiers and contractors understand how they can vary across architectural design, aspect and location.”
Wood windows, he maintained, can achieve the highest ‘A’ class WERs, but also have the flexibility to give different mixes of U-, G- and L-values.
