To facilitate the assessment of the feasibility, opportunities and weaknesses of advanced Heating, Ventilation and Air Conditioning (HVAC) control schemes we propose the remotely accessible KTH open testbed for smart HVAC control. This testbed allows researchers from all over the world to test estimators and controllers on a real facility, and aims to become a benchmark for the evaluation of the effectiveness of the control schemes proposed in the literature. This demo describes the testbed through a series of videos and Graphical User Interfaces (GUIs), and illustrates the potentialities and limitations of the remotely accessible hardware.