PVCu Windows: A Green Option?

Speak to almost any ecologist and plastic windows will get a pretty frosty reception. The general view is that, compared to the overall lifecycle of their timber equivalents, they are a pretty unsustainable substitute. And, up until recently, that view would have been generally justified.

So what’s changed? Well, one interesting development is at the Telford headquarters of one of the UK’s leading PVCu window manufacturers, Swish. This development does not relate to the quality of Swish’s products, but to the company’s commitment to recycling. Post-industrial recycling (PVCu that never became a window frame) is a well-trod path, but Swish has virtually pioneered the process of recycling post-consumer PVCu (old window frames). Post-consumer recycling presents its own set of problems and Swish has developed a plant to clean and sort out the metal and rubber and separate the various colours to leave a clean, usable raw material.

“From each tonne of material we receive at the plant,” says Gareth Parton of Swish, “about 5% is unusable – broken pallets, bits of wood, old coffee cups – and of the remainder we recover virtually 100%. Even the dust in the air extract system is recovered.” Swish’s plant currently processes about 23,000 tonnes of PVCu per year, or about 5,000 window frames each week. This is a fairly small proportion of the 300,000 tonnes of PVCu produced annually for windows in the UK, but it is around 50% of the recycling market. “The problem is getting the feed-stock,” says Gareth Parton. “The good installers are happy to send the old frames back to us. It is the cowboys who would rather dump a frame in a skip down the road that are the problem.” Swish is working hard to get the message across to homebuilders, improvers and installers — that PVCu is recyclable and that the company is ready, able and eager to recycle it.

Sustainability is about many things, not least durability — materials that will last. A recent study of social housing in Wales found that low-quality, cheap products, typically used for downpipes, had a realistic life of ten to 12 years. Better quality products might cost 50% to 100% more, but could last three times as long. PVCu uses about 50% of the oil, as a raw material, per tonne that other plastics use and it can be recycled ten to 12 times without loss of quality. That means that the manufactured PVCu can have a life of up to 300 years.

ABOVE: Swish’s plant in Telford takes delivery of 5,000 old PVCu window frames every week, granulates them down and eventually turns them into fully usable, clean, white material. Swish windows are made from 30% recycled material — the maximum allowed under current standards. The company is currently trying to increase this allowance to 100%

So are PVCu windows as sustainable as wooden ones? In terms of thermal performance there is little difference. Both industries insist that a good quality product, well maintained, will last. Wooden windows need more maintenance but have more flexibility in terms of design. It is the afterlife where the real distinction can be found.

The problem occurs with those products that do not go to recycling. A wooden window frame thrown into landfill will gently rot to nothing, having virtually no impact on the environment. A PVCu frame in landfill, however, will be there for hundreds of years. The PVCu frames now being landfilled are old PVCu, manufactured before the new standards were introduced, and will steadily leach the toxins used in their manufacture into the local environment.

It can therefore be argued that installing recycled PVCu windows and doors is beneficial to the environment as it prevents material going to landfill. It can also be argued that PVCu, and plastics generally, are the best use of our dwindling reserves of oil as the material can be used over and over again. Better at least than burning it in power stations and cars.

Swish has to be applauded for its pioneering work in developing an economically viable PVCu recycling plant. If the company can persuade more of us to demand recycled PVCu, it has the potential to change our perception of PVCu as a sustainable building material.

Further Reading:

• Positioning Windows
• Buying Windows
• A Guide to Windows & Doors