The new European norms regarding energy requirements, in particularly the European Performance Building Directive (EPBD), and system efficiencies of buildings have opened significant opportunities for the implementation of HVAC appliances. The first initial impact of the EPBD will be mainly related to heating systems. Condensing boilers, heat pumps, solar collectors are not the only means for achieving the energy saving goal. The term heat pump in today’s common HVAC contracting business is generally used for an electrically driven compressor device. In spite of this common conviction, in this paper practical experiences and field test data are presented for Air Source Gas Fired Absorption Heat Pumps. Heat generation appliances are generally over dimensioned in order to cover the peak heating loads related to winter design temperatures. In the last few years, however, appliances able to satisfy the efficiency requirements at partial load conditions with a high modulation ratio have become available. The system tested by ENEA represents an excellent example of this new technology: the combination between Air Source Gas Absorption Heat Pumps and high efficiency boilers will concur to optimally satisfy the market requirements and open new frontiers compared to traditional heating systems . In this article the experimental data from the field test carried out by ENEA at their facility in Casaccia, Rome will be discussed. In conclusion, the performance diagrams of the combined system will be used for the determination of seasonal heat generation efficiency according with CEN standards.