There is currently a global need to reduce the emission of greenhouse gases. Since buildings are the largest contributor to global warming emissions, improving their energy performance through the implementation of renewable energy technologies is a way forward to reduce energy use and thus carbon footprint. This article presents a new building envelope system that harvests solar energy through the steel skin of the facade of the building. The energy is generated by a steel sandwich panel featuring a modular design that enables full integration into the building envelope of both new constructed and refurbished buildings. The heat transfer means is a glycol and water mixture that flows inside a pipework arrangement embedded into the sandwich panel and connected to a distribution system. This distribution system deploys the energy generated into a buffer tank for further production of heating, cooling and domestic hot water through the use of a heat pump. The elements of this solar system were developed under the framework of the Building Active Steel Skin Envelope (BASSE) project funded by the Research Fund for Coal and Steel (RFCS). A detailed description of the components of the BASSE system as well as how they were developed is presented. Building on satisfactory thermal testing and the successful implementation of the system on a pilot building, the BASSE system was validated. The experimental results have shown that the coefficient of performance (COP) of the heat pump is in between 4.1-4.6. A validated simulation tool estimated that the cladding panel generates 3321.14 kWh/year which is 30.4% efficiency. Simulation results showed that a 35 BASSE panel installation on residential buildings subjected to temperate climate are Net Zero Energy Buildings (NZEB). Crown Copyright (C) 2019 Published by Elsevier B.V. All rights reserved.