Anything that is now removed during renovation or demolition no longer necessarily ends up at the waste disposal site. Increasing numbers of windows, doors and other materials are being fed into a recycling system after being dismantled and find their way back into the recovered substance cycle. This allows valuable resources to be preserved and energy to be saved.
As far as the ecological importance of UPVC windows compared to timber or aluminium is concerned, to date there are no concrete results that prove significant advantages or disadvantages of one specific window design in all environmental effects. Ultimately every building is unique and the aim is to find the right solution for each case.
If we look at the entire life cycle of UPVC windows — from the production of the raw materials and the processing of the materials to use and final disposal — the almost complete reusability has a clearly positive impact on the ecological balance. This is because 98% of the components of a UPVC window can be recycled and the valuable crude oil resource is preserved. The PVC from old windows can be reused at least seven times, with the quality and weather-resistance being maintained.
At the beginning of the 1990s, the first UPVC windows were collected and taken for recycling. What was still considered exotic at the time has become increasingly established over the years. More than 2,5 million UPVC windows were recycled across Europe in 2012. In Austria, for example, around 45.000 windows were converted into 895 tons of recycled plastic in 2009 — more than ten times the amount recycled in 2000. In Germany, Rewindo — an amalgamation of the leading German UPVC profile manufacturers — obtained around 22.000 tons of PVC recyclate from old windows, doors and roller shutters in 2012.
The recycling of UPVC windows is now supported by many manufacturers in the industry. Across the country, various initiatives have been created, such as the Österreichische Arbeitskreis Kunststoff-Fenster [Austrian working committee for UPVC windows] (ÖAKF), along with European amalgamations. The common goal is to consistently increase the reuse quota for old windows, in the context of a voluntary commitment by the European PVC industry to sustainable economies. Accordingly, the target is to be recycling 800.000 tons of UPVC windows annually in Europe by 2020.
A material that is easy to recycle is PVC (polyvinyl chloride). More than 60 years ago it became part of everyday life: Many basic commodities are made from this thermoplastic material — from mixers and kitchen clocks to headphones. However, the main area of use of PVC is in the construction industry. Almost 70% of the PVC produced annually in Europe is processed into building products — such as pipes, floor coverings, roller shutters, roof sheeting and: UPVC windows.
UPVC windows have been installed since the end of the 1960s and are being installed in ever increasing numbers. They are durable, robust and extremely weather-resistant and provide a high level of insulation. PVC as the basic material for these windows consists of 43% crude oil and 57% chlorine. As chlorine is a waste product that arises from electrolysis of common salt, no extra production is required to create PVC. In addition, no further materials are required for UPVC window profiles. These include stabilisers, which always used to contain lead. In 1994, Internorm was the first company in the world to develop and introduce a lead-free recipe. Other manufacturers subsequently changed over to lead-free connections.
In the early days of UPVC window recycling, the materials had to be broken down and recycled by hand. Today, this work is performed by clever machines. Internorm, for example, recycles waste that arises during the manufacture and PVC scrap in its own plant and forwards it on for extrusion.
In modern recycling plants such as that of the Internorm partner Rewindo in Behringen, Germany, the old window is no longer broken down into its component parts; instead, it is fed into a large shredder with its metal fittings, glass residues and gaskets. The materials are then separated in separation units. For example, metal components are removed from the flow of materials using a magnet. The PVC pieces are broken down further and cleaned. Thanks to digital optical recognition, white PVC can then automatically be separated from non-white PVC. During finishing, the PVC is granulated further and final foreign materials are filtered out.
What is left over is high-quality, pure PVC granulate. In the best quality it can now be used to manufacture new windows. The recycled iron, non-ferrous metals, other plastics and rubber are also available for further processing. Internorm uses old iron and aluminium to manufacture new profiles.