The old gymnasium of the school of Othmarsingen was completely renovated and energetically upgraded with an inside insulation. The renovation was completed in September 2015. A 200 mm thick Sto Perlite insulating pane was used on the inside of the insulation. The window reveals were insulated with 15 mm Sto Aevero aerogel insulation. Like that larger clear dimensions of the windows could be preserved. Without aerogel insulation a significant thermal bridge would have been created or the size of the windows would have been decreased.