Sustainable windows - planning for the future
Resource conservation starts with the window profile
The example of the window is a good illustration of the factors that influence the sustainability balance of a building element. It all starts with the production of the window profiles. In the case of PVC-U windows, they are made from a PVC compound, the synthesis of which in turn requires petroleum products and rock salt. As a result of modern window recycling, however, virgin PVC can increasingly be replaced here by high-quality PVC recyclate, and without any loss of quality. In profile production at VEKA, the proportion of this sustainable recycled material is already 26 percent.
The technically demanding profile extrusion also offers various starting points for more sustainability in terms of energy requirements. As part of company-wide initiatives, electricity consumption at VEKA has been halved in around 15 years. The company's own idea management system has played a major role in this: employees know their workplace inside out and repeatedly provide suggestions for successful optimization. However, the fact that the extrusion lines require a lot of space also has a favorable effect - all the more electricity VEKA generates with photovoltaic systems on the hall roofs.
The system provider also minimizes water consumption with a specially created wetland biotope at its Sendenhorst headquarters. The process water for cooling the extrusion lines is taken from this biotope. It then flows back there, supplemented by rainwater, and is treated in the constructed wetland for reuse. The throughput of this circulation system is no less than 136 million litres per year.
Modern windows mean energy efficiency
Old buildings are typically equipped with very simple windows that do not yet have the performance of modern windows. A comparison illustrates the consequences: although windows in old residential buildings only make up about 10 percent of the building envelope, they account for up to 50 percent of heat losses. This makes modernization all the more effective, with the installation of heat-insulating, state-of-the-art windows - not least in terms of heating costs.
Windows not only prevent heat from escaping. The solar gains from incident solar radiation, whose thermal energy is then effectively retained in the building, can also noticeably reduce heating requirements. This is especially true for south-facing windows and balcony or patio doors, and here even more so for the generous elements of modern architecture. Excessive heating in summer can easily be prevented by elegant shading solutions.
Recycling closes the material cycle
The sustainability balance of the window can only be complete if it also includes the phase after use. Windows made of all common frame materials can be recycled without any problems - apart from the energy savings due to the good thermal insulation over many years, this is one of the most important factors for their sustainability.
VEKA took the initiative in recycling PVC-Uwindows in 1993. At that time, the Group started up the first recycling plant for PVC windows and doors in Behringen, Thuringia. It was soon proven that PVC window recycling works very well and is also economically feasible. In the meantime, the plant in Thuringia has been joined by two others in the UK and France. The combined annual capacity of the three plants is 100,000 tonnes of old windows and doors as well as shutters and profile sections made of PVC-U.
The recycling process developed by VEKA delivers PVC granulate that is almost pure in terms of colour and type and can be fed directly back into the production of new window and door profiles without any loss of quality. In addition, ferrous and non-ferrous metals, glass and sealing rubber accumulate as further material fractions, which in turn can be fed into a new use. In this way, the entire PVC-U window is effectively reused: The material cycle is thus closed and new PVC-U windows can be manufactured in a way that is all the more resource-efficient, which further increases their sustainability.
