The past decades have seen an advancement from heavyweight radiant floors to lightweight conditioning ceiling systems. However, the performance of these lightweight systems are seldom comprehensively discussed in an informative manner for designers. This paper reviews lightweight radiant ceiling panel designs and conducts instrumental experiments to examine the thermal performance of different designs. Four distinct capillary hydronic panels have been designed and developed to assesses their thermal performance via empirical testing and measurement. Prototypes were built and integrated into a suspended ceiling system where they were tested in cooling mode. The response time, surface temperature, and energy transfer of the different panel designs were investigated. The experiment results show that higher thermal mass yields higher heat transfer and better surface temperature, but longer response time. A better thermal connection between the capillary tubes and the radiant surface also results in better conduction, faster response times, and improved surface temperature.