Floor heating has been the most basic version of panel heating and cooling systems since ancient times. Recently newer applications are becoming widely used, especially in Europe. For all panel applications, whether the most basic or the most innovative, their attributes are mainly focused on energy efficiency and better comfort. So far, little attention has been paid to their exergy efficiency, which in fact is a more insightful means of analyzing and comparing HVAC systems to optimally resolve the quadrilemma of human comfort, environment, energy, and economy. This paper shows that panel systems, especially when coupled with a convective component in a hybrid HVAC panel, are more exergy-efficient when they are tied into low-exergy energy sources. A typical analysis for a residential home indicates that the exergy efficiency of a hybrid panel utilizing a low-enthalpy energy resource and a heat pump is almost tenfold higher than a forced-air system utilizing natural gas and grid electricity. This paper draws an energy-based roadmap for the next-generation HVAC systems.

Units: Dual