Historical windows preserved through renovation : Date:
When renovating a historic building, the first thing that is often done is to replace the leaking wooden windows. A team of scientists at Stuttgart University of Applied Sciences is investigating – with funding from the Federal Ministry of Education and Research – how these can be maintained without compromising on energy savings.
The windows in historical buildings are a testimony of the era in which they were constructed. The structure and decorative fittings not only allow conclusions to be drawn about the period, but also show the building traditions in the region. Box or composite windows made of pine, spruce or oak – with their glazing bar spacing and filigree frame profiles – have a significant influence on the appearance of a building.
However, anyone who sees old, warped and draughty wooden windows as a building owner must also think about the future. It is important to be able to continue to maintain the building, which is why such windows are often completely replaced nowadays. But are there ways to preserve the windows and thus the character of the building – and still save energy? Which construction methods are particularly suitable for this? And how can technologies such as thermal insulation glazing contribute to this?
Together with their colleagues in the ENO.SAFE project, Professor Markus Binder from the Centre for Integral Architecture and Dr Andreas Beck from the Centre for Acoustic and Thermal Building Physics at Stuttgart University of Applied Sciences are looking for the answers to these and similar questions. The Baden-Württemberg State Office for the Preservation of Historical Monuments and Sites and specialised construction and restoration companies are also involved in the interdisciplinary project.
The aim of the project is to support the building owners in their decision for a renovation that preserves the historical fabric of the building. For example, windows can often be retained to a large extent if the appropriate renovation options are known. Sometimes only parts of the frames that have been particularly stressed by the weather need to be replaced. The old single-glass panes can then be replaced by well-insulating thermal insulation glazing. Additional seals prevent an uncomfortable draught.
To this end, the scientists in the ENO.SAFE project are investigating how much energy can best be saved with different window types and by which measures. They obtain the data from their own calculations, from measurements on buildings that have been renovated in various ways, but also from the evaluation of international studies on this subject. The results form the basis for a digital program to support decision-making in the field of renovation.
This program is intended to provide help not only to professionals such as planners, craftspeople and monument conservators, but also for laymen. If you enter the dimensions, frame material, window type and type of glazing, the program provides suggestions for suitable renovation measures. At the same time, it calculates how much energy can be saved per year through these measures. For this purpose, not only the so-called heat transfer coefficient is determined, which indicates how much heat flows through the window to the outside, but heat losses via adjacent building components such as natural stone edgings and leaking joints are also considered. In addition, the program is intended to offer further tips for the renovation of old windows in the form of short texts and pictures. Thus, the researchers in the ENO.SAFE project hope to contribute to better preserving the cultural heritage of historic buildings.
The Federal Ministry of Education and Research is supporting the ENO.SAFE project with about 182,200 euros within the framework of the FHprofUnt funding line as part of the Research at Universities of Applied Sciences programme.