The architecture forum at glasstec 2024 takes this area of tension as its starting point. One focus is on building in existing buildings, which - with the right design - can make massive savings in terms of gray energy and resources. The examples presented by the speakers will show how coherent architectural concepts can be created from often conflicting requirements. Among other things, it will become clear how glass can be integrated into contemporary building envelopes as an energy-intensive but indispensable component.