The WWA made the claim after the BRE’s Green Guide awarded wooden windows a higher grade in its climate change indicator rating, based on the CO2 emissions associated with their production, compared with those made from PVCu and aluminium. It is one of 13 criteria assessed in the Green Guide to produce an overall rating from A+ to E, where A+ represents the best environmental performance and E the lowest (ENDS Report 401, p 26 ).
The ASA found that the advert did not make it clear the grades were not the overall rating given to wooden windows in the Green Guide. It said the statements that "now wood comes top of the class for climate change, too" and "they’re the best choice to help combat climate change" were ambiguous.
It added that small print in the advert stating "wood windows also receive the highest overall ratings (A+ or A) in the Green Guide" would lead readers to infer that the grades referred to the products’ total environmental impact, not just one aspect. It also implied that plastic and aluminium had a much lower rating than wood in terms of environmental impact, even though PVCu windows were given the same overall grade.
The challenge is the latest in a string of confrontations between the PVC industry and makers of wooden window frames over green issues. In January 2008, PVC window makers hit back at timber firms’ claims that their windows were the "best environmental choice" (ENDS Report 396, p 23 ).