AWS 75 SI+ (Super Insulation) emphasises very good thermal insulation, design flexibility and compatibility with the AWS 75 system platform, while the AWS 75 BS.SI+ (Block System Super Insulation) is a variant of the AWS 75 series configured as a block window system with concealed vent frames (no visible sash/vent contour) and is aimed at very high architectural/thermal-performance applications. Schüco’s uPVC system is a 7-chamber PVC-U profile focused on excellent energy efficiency, airtightness and cost-effective performance; it offers passive-house-capable insulation, strong sealing through weldable EPDM gaskets, and versatile design options, making it ideal for residential builds that need high thermal performance with a more economical, low-maintenance material.