The thermally activated building panel (1) includes a metal plate (2) having a room-facing surface (3) and a building-facing surface (4). A heat-exchanger tube (5) for conveying a cooling or heating medium is in conductive thermal contact with the building-facing surface (4) of the metal plate (2). A textile (9) is arranged on the room-facing surface (3) of the metal plate (2) and has a first surface (10) generally contacting the metal plate (2) and a second surface (11) generally visible from said room. The textile (9) is tensioned between opposed edges (12) of the metal plate (2). The first surface (10) of the textile (9) is metallized by deposition of metal particles on the textile (9).