Hi everyone
Interior insulation never provides as much as full-surface exterior insulation, because at the latest at the partition walls a thermal bridge to the exterior walls occurs. A typical insulation thickness today is about 160 - 220 mm. This is not achievable with interior insulation. Then windows and roof insulation also play an important role. All together ensures good thermal insulation.
Best regards Baubetreuungsbüro Dreissigacker