Human comfort is the main goal of the different air conditioning systems. In modern systems, the radiant panels are used in rooms, because they produce a low noise levels and the required equipment are few. In this work, two types of radiant panels were used; an electric heating panel was used in a scale room model for heating process, while radiant cooling panels with cooling coils were used in a typical full scale room for cooling process. The two processes were studied experimentally and numerically. A numerical model was also employed to study flow pattern inside the rooms and to predict temperature distributions. The flow field was obtained by solving the flow governing equations for continuity, momentum and energy equations. The turbulent flow was solved by using Re-Normalization Group RNG k-? turbulent model. Heat transfer by radiation was modeled by using Discrete Ordinates DO radiation model. The results showed that the radiant panel systems achieved thermal comfort.