PVC? Is it still controversial? I've had several people ask what do I think about PVC windows?
Well back some 12 years ago Greenpeace released a report 'PVC-u or timber windows- Which is best?', that was uploaded onto their website three years ago - this report which showed that "the production and disposal of PVC-u windows leads to the release of highly poisonous chemicals which threaten the environment and human health. PVC-u production involves no less than six of the fifteen most hazardous chemicals listed by European governments for priority elimination. Timber is a sustainable resource. As long as the timber is sourced from properly managed forests and care is taken in the choice of preservatives, paints and stains, timber windows are by far the best environmental choice."
However things have changed - there is more recycling although this is still far, far too limited - many thousands of tonnes apparently still goes to landfill or incineration - and even in the trade it seems there are frustrations with vast amounts still going to waste - here's one comment I found: "What I found frustrating is that all these uPVC recycling companies are struggling to get hold of enough uPVC to recycle, yet so much is going to landfill!"
Check out this company website www.dekura.co.uk/ who recycle waste in the manufacture of windows and doors.
The environmental impact stem, firstly from its high chlorine content, with pure PVC composed of 57% chlorine by weight and secondly from its additives. These can include lead, cadmium organotin compounds and phthalates. Cadmium, a toxic heavy metal, was phased out by EU manufacturers in 2001, but will have been used in building products prior to 2001. (Whilst it is still used in PVC products imported from outside the EU, these have a very limited share of the EU construction market). The poisonous nature of its components has led the Fire Brigades Union to express concerns about PVC-based materials used in the construction of buildings due to the toxic emissions released when they burn.
The main hazard comes on disposal. It is said that the additives can leach out in landfill or contaminate ash and flue gas on incineration. However, it is the PVC itself that presents the main concern. On incineration, PVC produces significant amounts of hydrochloric acid. In addition, traces of highly toxic dioxin is also formed despite careful control. Greenpeace has pointed out that because of the neutralising salts that have to be added to uPVC when it is incinerated to counteract the hydrochloric acid produced, each tonne of uPVC incinerated can produce over two tonnes of contaminated waste that must be landfilled.
A significant amount of PVC is still landfilled. The fate of PVC over decades and centuries is unclear. Accelerated tests of landfill conditions have not shown breakdown of PVC, however these are short term tests and do not claim to predict the behaviour of PVC over centuries. In the short-term, some of the additives like phthalates are known to leach out in landfill conditions.
However the PVC industry is strong about countering these claims - you can read their fact sheets at: www.fightingbackwithfacts.com
Of course a lot of that is disputed - timber is said to last longer and is clearly more sustainable - here's a quote: "Modern timber windows are made from certified sustainable sources, and as trees are renewable its source is endless. PVC however uses the earths limited oil reserve, production and disposal of PVC windows involves 6 out of the 15 most hazardous chemicals listed by European governments for priority elimination. It may be a cheaper alternative but
the planet cannot afford it."
Research conducted by the BBC has shown that the use of plastic windows in period properties can knock up to £12,000 off their value - and the British Plastic Industry advises to consider other materials over plastic in period properties (Source PVC Aware pvcaware.org) - and the installation of uPVC windows is currently still banned in many Conservation Areas.
In terms of costs it is hard to find reliable info - indeed I've found a collection of stuff....at one end a costing a while back for Manchester City council reported that timber windows would be 22% more costly than PVCu over a 30 year period. Others show that windows made of other materials have whole life costs which are lower if not comparable to PVCu windows. One such was by Carlisle City Council between PVCu and high performance softwood double glazed units. It found that PVC-u windows were initially 25% more expensive and with negligible difference in costs over a 30-year period. The cost for timber was based on a five-year cycle of water-based staining and a maintenance allowance for PVCu. The Building Performance Group also reached a similar conclusion.
A whole life costing by Camden Council Housing indicates that timber would be 24% cheaper than PVCu over a 60 year life. This was based on a 20 year life for PVCu, 60 year life for timber, a 7 year paint cycle for timber and hinge, gasket and glazing maintenance for both windows. Camden Council's Green Buildings Guide states: "uPVC windows do degrade, they are not maintenance-free and worst of all they cannot be repaired when necessary". They cite the National Building Federation's report "Standards and Quality in Development" which gives uPVC windows a life expectancy of 20-25 years. New high performance softwood double-glazed windows are available with a far longer life that their uPVC counterparts. However some PVC can last 35 years - or is at least claimed to - and timber also needs maintenance.
A Greenpeace report "Implementing Solutions: Briefing No. 1: Installing New Windows" says: "If PVC-u windows are not cleaned regularly they quickly become permanently discoloured by dirt retention. They cannot then be restored to a nearly new condition. Sunlight causes PVC to go brittle, turn yellow and it can develop hairline cracks". They cite the policy of HAPM (Housing Association Property Mutual), the major defect insurer for housing associations, that PVC-u windows must be cleaned every six months, lubricated and adjusted annually and have weather stripping and gaskets renewed every 10 years. The Greenpeace archive has a list of alternatives to PVC here.
So taking all of this ramble into account in my opinion timber still rules!