Leading timber windows boss Roy Wakeman said it “beggars belief” that PVCu windows have gained an “A” rating in the new edition of the BRE’s Green Guide.

The Green Guide, published a few weeks ago, shows improved ratings for timber windows up to “A+”, but also crucially a big jump for plastic, with PVCu units moving up from a “C” to an “A” rating.

Mr Wakeman, chief executive of the Performance Window Group, said the environmental argument between timber and PVCu had been clear to him since joining the timber trade in the 1960s, with timber being a renewable natural resource and PVCu’s main ingredient, oil, having only finite supplies.

“So it beggars belief that we read PVCu can get an A-rated credential in the latest BRE Green Guide on the basis that more PVCu windows are being recycled. What a superb job the consolidated capital behind the plastics industry is doing.”

But Mr Wakeman said the guide clearly recognised timber’s environmental creditability by rating wood window products as “A+”, “putting timber back to its leading position as the ideal material from which to make performance products for the modern consumer”. And he singled out timber windows’ “A” rating in the Global Warming Potential category, compared to “D” for plastic and aluminium.

“As the consumer is becoming more aware of the need to conserve the Earth’s natural resources through daily press on the subject, and by the government and international initiatives such as the Code for Sustainable Homes, we will continue to see improved demand for our products,” he said.

The Green Guide aims to help designers and specifiers make the best environmental choices when selecting construction materials and components.