Comparative energy and comfort analysis of radiant floor versus all-air heating systems in a climate-controlled room

The widespread transition to low-temperature heating systems has intensified the debate of whether air-based or water-based heat carriers offer superior thermal comfort and energy performance. Although radiant floors are commonly renowned for their efficiency and stability, comprehensive studies comparing them with convective systems under strictly equivalent comfort conditions remain scarce. This research investigates the thermo-physiological and energetic trade-offs between Air-Dominant and Water-Dominant configurations within the CORE-CARE laboratory, a climate-controlled room allowing for the independent regulation of air flow and surface temperatures. The experimental phase involved subjecting participants to two-hour sessions in both setups: warm air heating through mechanical ventilation and radiant floor heating, while maintaining a neutral Predicted Mean Vote (PMV = 0). Subjective thermal sensation was recorded using Fanger’s scale to assess whether theoretical neutrality corresponded to perceived comfort. Parallel to the experiments, a dynamic model of the facility and its HVAC systems was developed and validated in OpenModelica by cross-referencing simulated data with experimental temperature profiles. To evaluate energy efficiency, the validated model was used to simulate a critical heating month under a realistic office occupancy schedule. By constraining both virtual systems to the same neutral PMV target, the study quantifies and compares the primary energy consumption of each configuration, providing a holistic evaluation of the optimal heating strategy for modern built environments.