This study focuses on air-source heat pump (ASHP) refrigerant-direct radiant systems, conducting field performance testing research. An integrated field performance testing system was developed incorporating compressor performance curve method, electrically heated refrigerant enthalpy difference method, and outdoor air enthalpy difference method. Through empirical comparative analysis, the measurement accuracy and applicability of these approaches were evaluated, establishing a methodological foundation for field performance testing of ASHP refrigerant-direct radiant systems. The results demonstrate measurement accuracies of ±5.5% for the compressor performance curve method, ±11.0% for the electrically heated refrigerant enthalpy difference method, and ± 11.0% for the outdoor air enthalpy difference method. The compressor performance curve method achieves the highest accuracy but requires complete compressor operational data. The electrically heated refrigerant enthalpy difference method carries inherent system disturbance risks, the outdoor air enthalpy difference method non-intrusive nature enables more authentic characterization of actual system operating conditions. This study provides empirical validation for field performance testing research to refrigerant-direct heat pump systems. The research results establish a methodological foundation for performance evaluation of ASHP refrigerant-direct radiant systems.