PVC windows were found to be less sustainable and more hazardous than wood in the report Window of opportunity: The environmental and economic benefits of specifying timber window frames.
WWF is encouraging specifiers and buyers of windows to choose wood which has been certified by the Forest Stewardship Council (FSC). This guarantees the wood has been sourced from a well-managed forest or other controlled wood source, and ensures that the timber is legal and not from a controversial source.
In comparison, PVC is made from a non-renewable source - oil - which makes up to 43 per cent of the raw material required to make PVC. PVC windows also generate more waste and use eight times more energy to manufacture than timber windows. The report also states that hazardous chemicals are released into the environment during one of the methods of PVC disposal - incineration.
The report shows that throughout the use and disposal of the product, the overall environmental impact is significantly less for timber windows than for PVC windows.
Christian Thompson, forests officer, at WWF, said: "WWF believes that timber is a genuinely renewable resource if managed responsibly which is why we urge specifiers and buyers to choose FSC-certified wood.
"This report clearly shows that PVC windows are far from environmentally friendly and I hope it will go some way to dispelling the myth that they are a green choice."
The report is written for specifiers and buyers, such as procurement managers in government departments, who are in the difficult position of having to make decisions on the most economical and environmentally responsible window to specify or buy. This includes ensuring that their commitment to cost-effective purchasing is met.
WWF is working to increase the availability of wood from well managed forests, such as products certified by the FSC, on the market in this country through the WWF-UK Forest & Trade Network (WWF-UK FTN). Members of the WWF-UK FTN, have committed to phasing out illegal timber from their supply chain and to increase the amount of credible certified material they source.
Window of opportunity
Download the report Window of opportunity as a PDF file.
To find out more about our work in this area, visit the forests section of our online Research Centre.
Forest & Trade Network
WWF-UK set up the Forest & Trade Network (FTN) to improve the management of the world's production forests by using the purchasing power of UK businesses. To find out more visit the Forest & Trade Network website .