In a long-running tussle for market share, the PVC industry has hit back at claims from wooden window framemakers that timber "is by far the best environmental choice for windows".
About 9.5 million window frames are installed in UK homes each year. Timber frames account for 12% of the market but they have been losing market share since 1990. Unplasticised PVC (PVCu) frames are the undisputed market leader.
The claim is the focus of a new marketing campaign by the Wood Window Alliance. The industry trade body says when timber is sourced from properly managed forests and the correct preservatives, paints and stains are used, it out-competes PVCu on environmental grounds.
But the WWA has yet to back up its claims with published research. It said it had finalised life-cycle assessments which will feed into the rating system for the BRE’s new Green Guide.
The guide tries to cut through the greenwash which is a characteristic of the window frames market. However, it is now prone to becoming out of date quickly. An updated version, initially due in 2007, has now been delayed until later this year.
Richard Lambert chief executive of the British Woodworking Federation said a "favourable outcome" that would "reassert timber’s sustainability credentials" was expected.
The WWA has also launched a labelling scheme to try to strengthen its green credentials.
To qualify, frames must meet performance standards, have a minimum 30-year service life and the timber must come from certified sustainable sources. This includes any source recognised by the government’s Central Point of Expertise on Timber (CPET) - a scheme panned by NGOs last year (ENDS Report 384, pp 21-22 ). Of the WWA’s 21 member manufacturers, all but one are accredited.
The PVC industry has hit back at the WWA’s claims, saying PVCu has the edge on energy efficiency grounds.
For decades PVC manufacturers have come under pressure from NGO campaigns focusing on waste and the toxicity arising from stabilisers and softeners used in the material: lead, cadmium, bisphenol-A and other phthalates (ENDS Report 274, p 45 ).
The industry has sought to mitigate its poor reputation through its Vinyl 2010 voluntary agreement. While concerns remain over the continued use of phthalates as softeners, cadmium stabilisers are no longer used and bisphenol A has been phased out. Lead is gradually being replaced, largely by calcium-based stabilisers.
Material recovery and recycling are also gaining momentum. A window waste collection scheme helped the industry collect and recycle 16,836 tonnes of PVC in the UK, up from 8,000 tonnes in 2005.
"By a massive margin the most important [impact] for a window system is the in-use phase," said Roger Mottram group environmental affairs manager at Ineos Vinyls.
"The industry has concentrated on making significant improvements in the in-use phase performance. This has paid dividends… PVC windows are being chosen for applications where energy efficiency is essential."
The Glass and Glazing Federation (GGF) claims poorly insulated windows accounts for 20% of all home heat loss, leading to 3.5 million tonnes of carbon dioxide being emitted.
Even Greenpeace, previously a strong PVC opponent, appears to have softened its stance. The PVC industry is quick to point out that 646 PVC windows are being used in the UK’s first solar-powered office block, sponsored by the government, the EU and Greenpeace at Northumbria University.
Last year, the British Fenestration Rating Council - part of the GGF - launched a A-E rating scheme to help specifiers and homeowners choose the most energy efficient windows on the market.1 Of the 93 products given the most energy efficient ‘A’ rating, 85 are PVCu, five are timber and three aluminium.
But the government thinks environmental impacts can be reduced further. The Environment Department (DEFRA) is currently developing a "product roadmap" for windows to reduce impacts along the supply chain (ENDS Report 391, pp 51-52 ). Publication is expected in May this year.